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Professor Richard Bush

Global Innovation Chair, International Centre for Balanced Land Use

School of Environmental and Life Sciences (Earth Sciences)

From the ground up

Prominent Australian Geoscientist Professor Richard Bush is the Global Innovation Chair at the International Centre for Balanced Land Use.

Based at the University of Newcastle's Newcastle Institute for Energy and Resources (NIER), the Centre is a joint partnership with the New South Wales Department of Industry through the NSW Department of Primary Industries and the Division of Resources and Energy.

“We aim is to harness the expertise of researchers across the University of Newcastle and the NSW Government to address the food, water and energy security challenges we face nationally and internationally. Most importantly, we are investigating issues of critical importance to the economic growth and sustainability of NSW,” Richard says.

The collaborative framework of the Centre provides a practical, independent, and multidisciplinary platform to directly inform policy and address complex issues related to economic, environment, and social balance in regional communities.

“Our research will help decision making processes by taking into account the needs of industry and community to inform policy and investment,” he says.

As a specialist in the area of land and water management, natural resource assessment, land use planning and geoscience based technologies, Richard Bush will be leading strategies to:

  • enhance community support for key regional industries;
  • reduce the impacts of agriculture and industry development on air, land, soil and water resources. This includes technologies and systems to rehabilitate land to highly productive uses for food production;
  • increase biodiversity offsets and improve water management.

The health and wellbeing of regional communities and their economies is an important focus for the Centre.

Current research efforts examine:

  • how communities can collectively stimulate regional economic growth;
  • the facilitation of multi-industry collaboration;
  • promotion of regional investment in education and infrastructure;
  • enhancement of health safety and environmental outcomes of regional workforces and communities.

Interdisciplinary Innovation

A specialist in the area of soil science and soil water interactions, Richard has published over 200 scientific reports and won in excess of $6 million dollars of competitive funding in the past five years.

Richard was a founding Director of Southern Cross GeoScience - a Special Research Centre of Southern Cross University with a focus on environmental and water systems.

With extensive experience gained from overseeing the large interdisciplinary Southern Cross team, Richard has a clear idea of how the new UON Centre will contribute to balanced land use outcomes.

“Genuine interdisciplinary research tackling significant, substantial or complex problems hopefully leads to innovation.”

Building a team

The Centre will have strong synergies with several UON research groups including:

“We see great benefit in bringing people together around shared objectives. Critical to our success will be exploring potential projects with government and industry partners.”

Impacting on policy

Collaborating directly with state government departments gives the International Centre for Balanced Land Use very clear connection to the research expertise in NSW government agencies and departments.

“We aim to work collaboratively to inform strategic decision making about how we balance critical resources like land, energy and water, Richard says.

“It's the capacity to sustain industry and at the same time protect the environment to balance quality of life with the capacity to produce.”

Learning from China

In 2016, Richard was awarded a fellowship with the Chinese Academy of Science, where he will be collaborating with the Academy’s Research Institute for Ecology and Water Quality. Richard will be studying the impacts of the Three Gorges Dam project.

“Studying another society with land and water challenges would be very helpful, particularly as our Centre and research mission is as much international, as national,” Richard says.

“Regional communities in Australia are in transition. There is increased opportunity for innovative intensive agriculture and a need to diversify resource intensive regions into more dynamic and innovative economies.”

“We can learn from the vitality and the tenacity of China to bring about change, to see what works for them and what doesn’t.”

Richard Bush

From the ground up

Professor Richard Bush is heading UON's International Centre for Balanced Land Use.

Read more

Career Summary

Biography

Professor Richard Bush is a prominent Australian geoscientist and founding Global Innovation Chair to the International Centre for Balanced Land Use. Based at the University of Newcastle's (UON) Newcastle Institute for Energy and Resources (NIER), the Centre is a multimillion dollar collaboration with New South Wales Department of Primary Industries and the Department of Industry's Division of Resources and Energy. The Centre draws together the research expertise within NSW DPI, NSW DRE, and the University to collaborate with industry and communities on projects of critical importance to the growth and sustainability of regional NSW. Professor Bush has a central role in developing worldclass research programs, facilitating cross-institutional collaboration and influencing national and international policy. Evidence based policy that incorporates objectives for economic, environmental and social balance are the foundation for balanced land use in practice. Professor Bush is a specialist in the area of land and water management, natural resource assessment, land use planning and geoscience based technologies. He has worked with industry, government and academia, published over 200 scientific reports and in the past 10 years has won in excess of $10 million dollars of
competitive funding to support his research.

Qualifications

  • Doctor of Philosophy, University of New South Wales
  • Bachelor of Science, University of New South Wales

Keywords

  • environmental science
  • rivers
  • soil science
  • strategic land use
  • wetlands

Fields of Research

Code Description Percentage
040204 Organic Geochemistry 35
040608 Surfacewater Hydrology 30
040202 Inorganic Geochemistry 35

Professional Experience

UON Appointment

Title Organisation / Department
Global Innovation Chair, International Centre for Balanced Land Use University of Newcastle
School of Environmental and Life Sciences
Australia
Global Innovation Chair, International Centre for Balanced Land Use University of Newcastle
Newcastle Institute for Energy and Resources
Australia
Global Innovation Chair, International Centre for Balanced Land Use University of Newcastle
Office - DVC (Research and Innovation)
Australia

Academic appointment

Dates Title Organisation / Department
1/01/2005 - 31/12/2010 ARC ARF Fellow Southern Cross University
1/01/2003 - 31/12/2005 ARC APDI Fellow Southern Cross University
1/01/1999 - 31/12/1999 Postdoctoral Research Fellow CRC for Sustainable Tourism
Australia

Membership

Dates Title Organisation / Department
1/01/2017 - 31/12/2017 NSW Hunter Region Community Consultative Committee for Natural Resources NSW Hunter Region Community Consultative Committee for Natural Resources
Australia
1/01/2017 - 31/12/2017 Scientific Reference Panel on Acid Sulfate Soils, Murray Darling Basin Authority Murray Darling Basin Authority
Australia
1/01/2012 - 31/12/2017 Chair, Scientific Panel, National Acid Sulfate Soil Conference National Acid Sulfate Soil Conference
Australia
1/01/2012 - 31/12/2012 Organising Committee, National Acid Sulfate Soil Conference National Acid Sulfate Soil Conference
Australia
1/01/2010 - 31/12/2010 Appointed Independent Member, KYNA Community Consultative Committee, SA Government KYNA Community Consultative Committee, SA Government
Australia

Professional appointment

Dates Title Organisation / Department
1/01/2007 - 31/12/2015 Director, Southern Cross GeoScience Southern Cross University
1/01/2003 - 31/12/2005 Salinity Team Leader NSW Department of Land and Water Conservation
Australia
1/01/1999 -  Founding Partner Founding Partner, RISATEC Pty Ltd.
Australia
1/01/1994 - 31/12/1995 Scientific Officer (Soils and Water) NSW Agriculture
Australia

Awards

Award

Year Award
2015 Appointment in the “Program of High-end Foreign Experts"
State Administration of Foreign Experts Affairs (SAFEA)
2012 Australian Society of Soil Science Publication Medal
Society of Soil Science Publication
2010 Vice Chancellors Award for ‘Excellence in Research’
Southern Cross University
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Publications

For publications that are currently unpublished or in-press, details are shown in italics.


Chapter (15 outputs)

Year Citation Altmetrics Link
2011 Sullivan LA, Bush RT, Burton ED, Ritsema CJ, van Mensvoort MEF, 'Acid Sulfate Soils', Handbook of Soil Sciences Properties and Processes, Second Edition, CRC Press, London (2011)
2008 Keene AF, Bush RT, Cheetham MD, Erskine WD, 'Pool-riffle reformation and induced bed armouring in a sand-bed stream following river rehabilitation', Sediment Dynamics in Changing Environments, International Assn of Hydrological Sciences Press, Christchurch, New Zealand 576-583 (2008)
2008 Cheetham MD, Keene AF, Erskine WD, Bush RT, Jacobsen G, 'Connecting the disconnected: Longitudinal correlation of river terrace remnants', Sediment Dynamics in Changing Environments, International Assn of Hydrological Sciences Press, Christchurch, New Zealand 123-129 (2008)
2005 Keene A, Bush RT, White I, Erskine WD, 'A farmer¿s approach to stream and floodplain management using ¿natural sequences¿', Australian Stream Management Conference. Proceedings of the 4th Australian Stream Management Conference: Linking Rivers to Landscape, Department of Primary Industries, Water and Environment, Tasmania, Launceston, Tasmania (2005)
2002 Bush RT, Sullivan LA, 'Pyrite formation in estuarine sediments of eastern Australia', Acid sulfate soils in Australia and China, Science Press, Beijing 51-64 (2002)
2002 Bush RT, Sullivan LA, 'Iron monosulfide minerals in floodplain sediments of eastern Australia', Acid sulfate soils in Australia and China, Science Press, Beijing 131-142 (2002)
2001 Sullivan LA, Bush RT, 'Analysis and description of soil by microscopy', Describing, analysing & managing our soil, University of Sydney/Australian Society of Soils Science Inc., NSW Branch, Sydney 401-416 (2001)
2001 Bush RT, Sullivan LA, White I, 'Acid sulfate soil processes and management', Describing, analysing & managing our soil, University of Sydney/Australian Society of Soils Science Inc., NSW Branch, Sydney 259-275 (2001)
2001 Boyd WE, Bush RT, Clark MW, Smith JV, Sullivan LA, 'Contribution of geological process studies to environmental management: case studies from northeastern New South Wales and southeast Queensland', Gondwana to Greenhouse: Environmental Geoscience ¿ An Australian perspective, Geological Society of Australia Special Publication, . 257-265 (2001)
2000 Sullivan LA, Bush RT, Lancaster G, Clark MW, Lin C, Saenger P, 'Chromium Reducible Sulfur ¿ Method 22B', Acid Sulfate Soils Environmental Issues, Assessment and Management : Technical Papers, Queensland Department of Natural Resources, Brisbane 23-1-23-6 (2000)
2000 Sullivan LA, Bush RT, McConchie D, Lancaster G, Clark MW, Haskins P, et al., 'Chromium Reducible Sulfur for Acid Sulfate Soil Identification and Management', Remediation & Assessment of Broadacre Acid Sulfate Soils, Acid Sulfate Soil Management Advisory Committee, Wollongbar, NSW 16-21 (2000)
2000 Sullivan LA, Bush RT, 'The behaviour of drain sludge in acid sulfate soil areas: some implications for acidification of waterways and drain maintenance', Remediation & Assessment of Broadacre Acid Sulfate Soils, Acid Sulfate Soil Management Advisory Committee, Wollongbar, NSW 43-48 (2000)
2000 Bush RT, Sullivan LA, White I, Prince K, 'Sulfur isotope evidence for the contemporary formation of pyrite in a coastal acid sulfate soil', Centre for Isotope Studies Research Review 1995- 1999, CSIRO Publishing, Australia 135-139 (2000)
2000 Bush RT, Prince K, White I, McGoldrick P, Sullivan LA, 'Secondary Ion Mass Spectrophotometry (SIMS) with extreme energy filtering for micron scale delta34S determinations of pyrite', Centre for Isotope Studies Research Review 1995-1999, CSIRO Publishing, Australia 139-143 (2000)
1999 Bush RT, Sullivan LA, 'Greigite and magnetic susceptibility of some coastal floodplain soils', Geodiversity: Readings in geography at the close of the 20th century, chool of Geography and Oceanography, Australian Defence Force Academy, Canberra, Australia 373-380 (1999)
Show 12 more chapters

Journal article (105 outputs)

Year Citation Altmetrics Link
2018 Choppala G, Kunhikrishnan A, Seshadri B, Park JH, Bush R, Bolan N, 'Comparative sorption of chromium species as influenced by pH, surface charge and organic matter content in contaminated soils', Journal of Geochemical Exploration, 184 255-260 (2018) [C1]
DOI 10.1016/j.gexplo.2016.07.012
Citations Scopus - 5Web of Science - 2
Co-authors Nanthi Bolan, Balaji Seshadri
2018 Ling YC, Gan HM, Bush M, Bush R, Moreau JW, 'Time-resolved microbial guild responses to tidal cycling in a coastal acid-sulfate system', Environmental Chemistry, 15 2-17 (2018) [C1]

© CSIRO. Environmental context Microbes play key roles in controlling acidification and metal toxicity in coastal acid-sulfate soils. We characterised the time-dependent metabolic... [more]

© CSIRO. Environmental context Microbes play key roles in controlling acidification and metal toxicity in coastal acid-sulfate soils. We characterised the time-dependent metabolic activities of abundant and rare taxa in acidifying tidal wetlands and showed that rare taxa exhibiting higher activity may exert significant influence on iron- and sulfur-cycling. Our findings yield new insights into the drivers and timing of iron- and sulfur-cycling in coastal acid-sulfate systems. Abstract Tidal inundation has been trialled as a remediation strategy for coastal acid-sulfate soil (CASS) environments. Microbial community structure and activity are hypothesised to play key roles in this process, but remain poorly understood for long-term (decadal or longer) CASS ecosystems. More detailed understanding of the distribution and timing of microbial activity in CASS ecosystems is necessary to evaluate their real bioremediation potential. In this study, we compared 16S ribosomal DNA (rRNA) and RNA (as copy DNA, cDNA, a proxy for overall enzymatic activity) sequence datasets to characterise and resolve microbial community structure and activity across a tidal cycle in the East Trinity long-term CASS wetland (Queensland, Australia). The timing and extent of activity among abundant (>1 %) and rare (<0.1 %) microbial taxa showed that a larger number of rare members (phylotype) displayed greater overall range in activity than was apparent for more abundant members. Certain taxa from both abundant and rare populations varied rapidly in their 16S rRNA levels in response to tidal cycling. The observation of rRNA accumulation in response to drying and rewetting was used to divide the microbial community structure into 'early responders' (within 3 h of dry-down or wet-up) and 'delayed responders' (3+ h after wet-up). Response patterns were phylogenetically constrained across supra- to subtidal zones across all tidal stages. Microbial iron- and sulfur-cycling networks included these rare but active taxa, illustrating their spatiotemporal complexity, which should be considered for an accurate assessment of bioremediation efficiency, and specially for validating predictive biogeochemical models of long-term CASS ecosystems.

DOI 10.1071/EN16203
Citations Scopus - 1Web of Science - 1
2018 Choppala G, Moon E, Bush R, Bolan N, Carroll N, 'Dissolution and redistribution of trace elements and nutrients during dredging of iron monosulfide enriched sediments', Chemosphere, 201 380-387 (2018) [C1]

© 2018 Elsevier Ltd The increased use of estuarine waters for commercial and recreational activities is one consequence of urbanisation. Western Australia&apos;s Peel-Harvey Estua... [more]

© 2018 Elsevier Ltd The increased use of estuarine waters for commercial and recreational activities is one consequence of urbanisation. Western Australia's Peel-Harvey Estuary highlights the impacts of urbanisation, with a rapidly developing boating industry and periodic dredging activity. The aim of this research is to evaluate the potential mobility of nutrients and trace elements during dredging, and the influence of flocculation on iron and sulfur partitioning in iron monosulfide enriched sediments. Our findings indicate a short-term increase in nitrate, phosphate and ammonium, during dredging through the resuspension of sediments. However, no increase in metal mobilisation during dredging was observed except copper (Cu) and zinc (Zn). Flocculant addition increased the release of nutrients, zinc (Zn) and arsenic (As) from sediments, had no effect on acid volatile sulfides and pyritic sulfur, but corresponded with an initial sharp rise in elemental sulfur concentrations. The run-off water from geofabric bags should be treated to decrease the concentrations of Zn and As to their background levels before releases into the estuary. Long-term impact of dredging on organic matter mineralisation and its subsequent effect on nutrients and trace elements dynamics needs further investigation.

DOI 10.1016/j.chemosphere.2018.01.164
Co-authors Nanthi Bolan
2018 Li S, Bush RT, Santos IR, Zhang Q, Song K, Mao R, et al., 'Large greenhouse gases emissions from China's lakes and reservoirs', Water Research, 147 13-24 (2018) [C1]
DOI 10.1016/j.watres.2018.09.053
2018 Li S, Ni M, Mao R, Bush RT, 'Riverine CO

© 2018 Elsevier B.V. Rivers are an important source of CO2to the atmosphere, however, mountainous rivers and streams with high emission rates are not well studied particularly in ... [more]

© 2018 Elsevier B.V. Rivers are an important source of CO2to the atmosphere, however, mountainous rivers and streams with high emission rates are not well studied particularly in China. We report the first detailed investigation on monsoonal mountainous rivers in the Three Gorges Reservoir (TGR) region, with a focus on the riverine CO2partial pressure (pCO2), CO2degassing and their potential controls. The pCO2levels ranged from 50 to 6019 µatm with averages of 1573 (SD. ±1060) in dry Autumn and 1276 (SD. ±1166) µatm in wet Summer seasons. 94% of samples were supersaturated with CO2with respect to the atmospheric equilibrium (410 µatm). Monsoonal precipitation controlled pCO2seasonality, with both the maximal and minimal levels occurring in the wet season, and showing the overall effects of dilution. Riverine pCO2could be predicted better in the dry season using pH, DO% and DTP, whereas pH and DOC were better predictors in the wet season. We conclude that in-situ respiration of allochthonous organic carbon, rather than photosynthesis, resulted in negative relationships between pCO2and DO and pH, and thus CO2supersaturation. Photosynthetic primary production was effectively limited by rapid flow velocity and short residence time. The estimated water-to-air CO2emission rate in the TGR rivers was 350 ± 319 in the Autumn and lower, yet more variable at 326 ± 439 mmol/m2/d in Summer. Our calculated CO2areal fluxes were in the upper-level magnitude of published data, demonstrating the importance of mountainous rivers and streams as a global greenhouse gas source, and urgency for more detailed studies on CO2degassing, to address a global data gap for these environments.

DOI 10.1016/j.jhydrol.2018.01.057
Citations Scopus - 3Web of Science - 2
2018 Li T, Li S, Bush RT, Liang C, 'Extreme drought decouples silicon and carbon geochemical linkages in lakes', Science of the Total Environment, 634 1184-1191 (2018) [C1]

© 2018 Elsevier B.V. Silicon and carbon geochemical linkages were usually regulated by chemical weathering and organism activity, but had not been investigated under the drought c... [more]

© 2018 Elsevier B.V. Silicon and carbon geochemical linkages were usually regulated by chemical weathering and organism activity, but had not been investigated under the drought condition, and the magnitude and extent of drought effects remain poorly understood. We collected a comprehensive data set from a total of 13 sampling sites covering the main water body of the largest freshwater lake system in Australia, the Lower Lakes. Changes to water quality during drought (April 2008¿September 2010) and post-drought (October 2010¿October 2013) were compared to reveal the effects of drought on dissolved silica (DSi) and bicarbonate (HCO3-) and other environmental factors, including sodium (Na+), pH, electrical conductivity (EC), chlorophyll a (Chl-a), total dissolved solids (TDS), dissolved inorganic nitrogen (DIN), total nitrogen (TN), total phosphorus (TP) and water levels. Among the key observations, concentrations of DSi and DIN were markedly lower in drought than in post-drought period while pH, EC and concentrations of HCO3-, Na+, Chl-a, TDS, TN, TP and the ratio TN:TP had inverse trends. Stoichiometric ratios of DSi:HCO3-, DSi:Na+and HCO3-:Na+were significantly lower in the drought period. DSi exhibited significantly negative relationships with HCO3-, and DSi:Na+was strongly correlated with HCO3-:Na+in both drought and post-drought periods. The backward stepwise regression analysis that could avoid multicollinearity suggested that DSi:HCO3-ratio in drought period had significant relationships with fewer variables when compared to the post-drought, and was better predictable using nutrient variables during post-drought. Our results highlight the drought effects on variations of water constituents and point to the decoupling of silicon and carbon geochemical linkages in the Lower Lakes under drought conditions.

DOI 10.1016/j.scitotenv.2018.04.074
2018 Li T, Li S, Liang C, Bush RT, Xiong L, Jiang Y, 'A comparative assessment of Australia's Lower Lakes water quality under extreme drought and post-drought conditions using multivariate statistical techniques', Journal of Cleaner Production, 190 1-11 (2018) [C1]

© 2018 Elsevier Ltd Drought generally results in a decline to freshwater quality, but the spatial nature of these impacts and recovery processes in large lakes systems remain poor... [more]

© 2018 Elsevier Ltd Drought generally results in a decline to freshwater quality, but the spatial nature of these impacts and recovery processes in large lakes systems remain poorly understood. This study applied multiple statistical methods such as cluster analysis (CA), discriminant analysis (DA), principal component analysis (PCA) and factor analysis (FA), to assess spatial and temporal variations of water quality in the Lower Lakes (Australia) during drought (April 2008¿September 2010) and post-drought (October 2010¿October 2013) periods. The comprehensive analysis of water quality from 22 locations and including 22 key parameters showed that Lower Lakes were eutrophic in both drought and post-drought periods with higher nutrient and algae concentrations than guideline levels for aquatic ecosystem. The Lower Lakes were identified three distinct spatial zones, i.e., (1) low eutrophication for the southeast of Lower Lakes (SE), (2) moderate eutrophication for northeast of Lower Lakes (NE), and (3) high eutrophication for northwest of Lower Lakes (NW) in the drought as well as low eutrophication for NW and high eutrophication for SE in the post-drought. DA allowed a better reduction in the dimensionality of the large dataset during post-drought than during the drought period with better results for spatial analysis rather than for temporal analysis regardless of hydrological periods. PCA/FA reflected three major factors of mineral dissolution, erosion and anthropogenic sources accounting for water constituents. Our results demonstrate the powerful utility of multivariate statistical techniques for revealing the persistent and spatially complex nature of drought-induced impacts on lake water quality and highlight that optimal utilization of water resources in the upper catchment of Lower Lakes are urgently needed for the sustainable lake ecosystems.

DOI 10.1016/j.jclepro.2018.04.121
2017 Moon EM, Bush RT, Gibbs DHM, Mata JP, 'Divergent Fe and S mineralization pathways during the oxidative transformation of greigite, Fe3S4', CHEMICAL GEOLOGY, 468 42-48 (2017)
DOI 10.1016/j.chemgeo.2017.08.007
2017 Tulipani S, Schwark L, Holman AI, Bush RT, Grice K, '1-Chloro-n-alkanes: Potential mangrove and saltmarsh vegetation biomarkers', Organic Geochemistry, 107 54-58 (2017)

© 2017 Elsevier Ltd Chlorinated hydrocarbons with biological sources occur in high abundance and diversity in living organisms as well as in sedimentary environments. Although som... [more]

© 2017 Elsevier Ltd Chlorinated hydrocarbons with biological sources occur in high abundance and diversity in living organisms as well as in sedimentary environments. Although some of these compounds are potentially highly source-specific and sufficiently degradation-resistant, their capacity as sedimentary biomarkers remains under-investigated. Distinct series of long-chain 1-chloro-n-alkanes have previously been reported in three species of European saltmarsh vegetation; however, these compounds have never been further investigated in a more diverse plant population. Here we report the presence of similar series with a typical higher plant odd/even carbon number predominance in species of Australian mangrove and saltmarsh vegetation, including the black mangrove Lumnitzera racemosa, the grass Sporobolus virginicus and samphire, supporting the potential use of long-chain 1-chloro-n-alkanes as halophyte biomarkers. Based on carbon stable isotope values, which were reported here for the first time, and similarities in their distributions, we propose that the biosynthetic pathway of chloroalkanes is linked to that of other n-alkyl plant wax components.

DOI 10.1016/j.orggeochem.2017.02.007
2017 Luke H, Martens MA, Moon EM, Smith D, Ward NJ, Bush RT, 'Ecological restoration of a severely degraded coastal acid sulfate soil: A case study of the East Trinity wetland, Queensland', ECOLOGICAL MANAGEMENT & RESTORATION, 18 103-114 (2017)
DOI 10.1111/emr.12264
Citations Scopus - 2Web of Science - 2
2017 Choppala G, Bush R, Moon E, Ward N, Wang Z, Bolan N, Sullivan L, 'Oxidative transformation of iron monosulfides and pyrite in estuarine sediments: Implications for trace metals mobilisation', Journal of Environmental Management, 186 158-166 (2017) [C1]
DOI 10.1016/j.jenvman.2016.06.062
Citations Scopus - 2Web of Science - 2
Co-authors Zhaohui Wang, Nanthi Bolan
2017 Li S, Bush RT, Mao R, Xiong L, Ye C, 'Extreme drought causes distinct water acidification and eutrophication in the Lower Lakes (Lakes Alexandrina and Albert), Australia', Journal of Hydrology, 544 133-146 (2017) [C1]

© 2016 Elsevier B.V. Droughts are set to increase in frequency and magnitude with climate change and water extraction, and understanding their influence on ecosystems is urgent in... [more]

© 2016 Elsevier B.V. Droughts are set to increase in frequency and magnitude with climate change and water extraction, and understanding their influence on ecosystems is urgent in the Holocene. Low rainfall across the Murray-Darling Basin (MDB) of Australia resulted in an unprecedented water level decline in the Lower Lakes (Lakes Alexandrina and Albert) at the downstream end of the river system. A comprehensive data covering pre-drought (2004¿2006), drought (2007¿2010) and post-drought (2010¿2013) was firstly used to unravel drought effects on water quality in the contrasting main parts and margins of the two Lakes, particularly following water acidification resulting from acid sulfate soil oxidation. Salinity, nutrients and Chl-a significantly increased during the drought in the Lake main waterbody, while pH remained stable or showed minor shifts. In contrast to the Lake Alexandrina, total dissolved solid (TDS) and electrical conductivity (EC) during the post-drought more than doubled the pre-drought period in the Lake Albert as being a terminal lake system with narrow and shallow entrance. Rewetting of the exposed pyrite-containing sediment resulted in very low pH (below 3) in Lake margins, which positively contributed to salinity increases via SO42-release and limestone dissolution. Very acidic water (pH 2¿3) was neutralised naturally by lake refill, but aerial limestone dosing was required for neutralisation of water acidity during the drought period. The Lower Lakes are characterized as hypereutrophic with much higher salinity, nutrient and algae concentrations than guideline levels for aquatic ecosystem. These results suggest that, in the Lower Lakes, drought could cause water quality deterioration through water acidification and increased nutrient and Chl-a concentrations, more effective water management in the lake catchment is thus crucial to prevent the similar water quality deterioration since the projected intensification of droughts. A comparative assessment on lake resilience and recovering processes should be undertaken with a post-drought monitoring program.

DOI 10.1016/j.jhydrol.2016.11.015
Citations Scopus - 7Web of Science - 7
2016 Li S, Bush RT, Ward NJ, Sullivan LA, Dong F, 'Air-water CO2 outgassing in the Lower Lakes (Alexandrina and Albert, Australia) following a millennium drought', Science of the Total Environment, 542 453-468 (2016) [C1]
DOI 10.1016/j.scitotenv.2015.10.070
Citations Scopus - 6
2016 Wong V, Cheetham M, Bush RT, Sullivan L, Ward N, 'Accumulation of sulfidic sediments in a channelised inland river system, southern Australia', Marine and Freshwater Research, 67 1655-1666 (2016) [C1]
DOI 10.1071/MF15080
2016 Choppala G, Bolan N, Kunhikrishnan A, Bush R, 'Differential effect of biochar upon reduction-induced mobility and bioavailability of arsenate and chromate', Chemosphere, 144 374-381 (2016) [C1]

© 2015 Elsevier Ltd. Heavy metals such as chromium (Cr) and arsenic (As) occur in ionic form in soil, with chromate [Cr(VI)] and arsenate As(V) being the most pre-dominant forms. ... [more]

© 2015 Elsevier Ltd. Heavy metals such as chromium (Cr) and arsenic (As) occur in ionic form in soil, with chromate [Cr(VI)] and arsenate As(V) being the most pre-dominant forms. The application of biochar to Cr(VI) and As(V) spiked and field contaminated soils was evaluated on the reduction processes [(Cr(VI) to Cr(III)] and [As(V) to As(III))], and subsequent mobility and bioavailability of both As(V) and Cr(VI). The assays used in this study included leaching, soil microbial activity and XPS techniques. The reduction rate of As(V) was lower than that of Cr(VI) with and without biochar addition, however, supplementation with biochar enhanced the reduction process of As(V). Leaching experiments indicated Cr(VI) was more mobile than As(V). Addition of biochar reversed the effect by reducing the mobility of Cr and increasing that of As. The presence of Cr and As in both spiked and contaminated soils reduced microbial activity, but with the addition of biochar to these soils, the microbial activity increased in the Cr(VI) contaminated soils, while it was further decreased with As(V) contaminated soils. The addition of biochar was effective in mitigating Cr toxicity by reducing Cr(VI) to Cr(III). In contrast, the conversion process of As(V) to As(III) hastened by biochar was not favourable, as As(III) is more toxic in soils. Overall, the presence of functional groups on biochar promotes reduction by providing the electrons required for reduction processes to occur as determined by XPS data.

DOI 10.1016/j.chemosphere.2015.08.043
Citations Scopus - 23Web of Science - 21
Co-authors Nanthi Bolan
2015 Wang Z, Xiao D, Bush RT, Liu J, 'Coprecipitated arsenate inhibits thermal transformation of 2-line ferrihydrite: Implications for long-term stability of ferrihydrite', Chemosphere, 122 88-93 (2015) [C1]

© 2014 Elsevier Ltd. 2-line ferrihydrite, a ubiquitous iron oxy-hydroxide found in natural and engineered systems, is an efficient sink for the toxic metalloids such as arsenic. W... [more]

© 2014 Elsevier Ltd. 2-line ferrihydrite, a ubiquitous iron oxy-hydroxide found in natural and engineered systems, is an efficient sink for the toxic metalloids such as arsenic. While much is known of the excellent capacity of ferrihydrite to coprecipitate arsenate, there is little information concerning the long-term stability of arsenate-accumulated ferrihydrite. By thermal treatment methodology, the expedited transformation of ferrihydrite in the presence of coprecipitated arsenate was studied at varying As/Fe ratios (0-0.5) and different heating temperature (40, 300, 450, 600. °C). Pure and transformed minerals were characterized by thermogravimetry (TG), X-ray diffraction (XRD), Electron Spin Resonance (ESR), Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDX) and Fourier Transform Infrared Spectroscopy (FTIR). Arsenate was found to retard the thermal transformation of ferrihydrite. The extents of ferrihydrite transformation to hematite decreased with increasing As/Fe ratios, but increased at a higher heating temperature. It is predicted that the coprecipitated arsenate can stabilize the amorphous iron oxides against the transformation to more crystalline solids. Arsenate concentration appears to play an important role in this predicted long-term stability.

DOI 10.1016/j.chemosphere.2014.11.017
Citations Scopus - 12Web of Science - 9
Co-authors Zhaohui Wang
2015 Kraal P, Burton ED, Rose AL, Kocar BD, Lockhart RS, Grice K, et al., 'Sedimentary iron-phosphorus cycling under contrasting redox conditions in a eutrophic estuary', Chemical Geology, 392 19-31 (2015) [C1]

© 2014 Elsevier B.V.. Phosphorus (P) is often a limiting nutrient within freshwater and estuarine systems, thus excess inputs of P from anthropogenic activities (dominantly agricu... [more]

© 2014 Elsevier B.V.. Phosphorus (P) is often a limiting nutrient within freshwater and estuarine systems, thus excess inputs of P from anthropogenic activities (dominantly agriculture) can induce eutrophication in receiving water bodies. The sequestration of P within estuarine sediments is controlled by sorption and precipitation processes, which are impacted by local redox conditions and burial environment. Despite the global spread of oxygen depletion in coastal marine systems, P burial under reducing conditions remains poorly understood. We investigated P cycling in relation to iron (Fe) redox chemistry in sediments from the eutrophic Peel-Harvey Estuary in Western Australia, using a combination of porewater analysis, sequential chemical P extractions, synchrotron-based micro-scale X-ray fluorescence mapping and Fe K-edge X-ray absorption spectroscopy, and PO43-sorption experiments. The sediments represented redox regimes varying from strongly reducing, organic-rich sediments with little or no reactive Fe(III) (oxyhydr)oxides to oxygenated sediments that were enriched in reactive Fe(III) phases. Organic P and Fe-associated P were the main P burial phases, and the latter was quantitatively important even in sediments with an overall strongly reducing character. We attribute this to adsorption of P onto micro-scale Fe(III) oxyhydroxide enrichments and/or Fe-bearing clay minerals. The organic-rich sediments showed a strong decline in P contents with depth; P was released from organic matter and Fe phases but apatite precipitation was apparently inhibited in these sediments. Despite greater and stronger PO43-sorption capacity, the oxic sediments contained relatively little P due to a lack of the primary P source in marine sediments: organic matter. Our results provide detailed insight into P burial in dynamic estuarine sediments and show that micro-scale spectroscopic analyses greatly advance our understanding of P sequestration processes.

DOI 10.1016/j.chemgeo.2014.11.006
Citations Scopus - 14
2015 Wong VNL, Johnston SG, Burton ED, Hirst P, Sullivan LA, Bush RT, Blackford M, 'Seawater inundation of coastal floodplain sediments: Short-term changes in surface water and sediment geochemistry', Chemical Geology, 398 32-45 (2015) [C1]

© 2015 . Coastal floodplains are highly vulnerable to seawater inundation as a result of storm surge and sea-level rise due to their low elevation and proximity to the coastline. ... [more]

© 2015 . Coastal floodplains are highly vulnerable to seawater inundation as a result of storm surge and sea-level rise due to their low elevation and proximity to the coastline. Intact soil cores from a levee, acid-sulfate soil scald and four backswamp sites on a coastal floodplain in eastern Australia were inundated with artificial seawater treatments (0%, 50% and 100%) for 14days to examine the short term consequences for surface water and floodplain sediment geochemistry. All sites displayed an initial decrease in surface water pH following inundation with 50% and 100% seawater. In addition, higher concentrations of trace metals (Al, Fe, Mn, Ni and Zn) were observed in most sites inundated with 50% or 100% seawater. This was generally attributed to competitive exchange and desorption of trace metals from sediments due to the higher ionic strength of the seawater solutions and upward diffusive flux of metals from the sediments to surface waters. At one backswamp site, reductive processes had established by day 7, which also resulted in elevated Fe2+concentrations in the overlying surface waters. Transmission electron microscopy (TEM) identified the presence of poorly crystalline ferrihydrite and schwertmannite, and goethite and jarosite. These meta-stable Fe(III) minerals can act as a source of metals for desorption and can also be readily reduced and act as a source of Fe2+to surface waters. Importantly, inundation with either 50% or 100% seawater resulted in a similar magnitude of acidity and trace metal mobilisation. The data suggest that an inundation event of ~0.2m depth with either 50% or 100% seawater could cause a pulse mobilisation of up to 64.8 and 9.1kgha-1of Fe and Al, respectively - quantities of similar magnitude to previous estimates of annual drainage fluxes from similar backswamps. This study suggests that the short term inundation of coastal floodplain sediments by either brackish water or seawater will result in rapid declines in surface water quality as a result of increased liberation of acidity and trace metals.

DOI 10.1016/j.chemgeo.2015.01.016
Citations Scopus - 4
2015 Vithana CL, Sullivan LA, Burton ED, Bush RT, 'Stability of schwertmannite and jarosite in an acidic landscape: Prolonged field incubation', Geoderma, 239 47-57 (2015) [C1]

© 2014 Elsevier B.V. Schwertmannite and jarosite are two of the main secondary iron(III) minerals commonly found in acidic, iron and sulfate-rich environments such as acid mine dr... [more]

© 2014 Elsevier B.V. Schwertmannite and jarosite are two of the main secondary iron(III) minerals commonly found in acidic, iron and sulfate-rich environments such as acid mine drainage and coastal acid sulfate soils (CASS). Both minerals exert major influence on the water and soil quality in these environments. While there are many studies conducted on the stability of these two minerals under controlled laboratory conditions, the behaviour of schwertmannite and jarosite under field conditions and the factors influencing their behaviour have not been investigated directly. In the present study, we examined the net transformation of introduced schwertmannite and jarosite samples incubated in a typical acidic CASS environment. Pure (synthetic) schwertmannite and jarosite samples were exposed to two main chemical regimes: 1) aerobic-acidic water column and 2) anaerobic-neutral sediment in a CASS environment. Changes in mineralogy, micromorphology, and composition of schwertmannite and jarosite samples were monitored over a period of 12months. Schwertmannite suspended in the water column and buried in sediments transformed to goethite by the end of 12months but more quickly in anoxic, reducing sediments. However, schwertmannite incubated in the acidic water column transformed at a much faster rate than those reported for acidic and aerobic conditions in the laboratory. Jarosite incubated in both the water column and sediments was also transformed to goethite but at a much slower rate than schwertmannite. Dissimilatory microbial reduction and Fe2+-catalysed transformation likely played a major role in accelerating the transformation of both minerals to goethite in sediments. The transformation of both minerals in the water column was sensitive to the hydrological conditions and fluctuations in the water column in relation to antecedent rainfall. In comparison, the sediment's geochemistry was relatively stable and consequently the rate of transformation and dissolution of both schwertmannite and jarosite in this environment was not appreciably affected by variable hydrology.

DOI 10.1016/j.geoderma.2014.09.022
Citations Scopus - 10Web of Science - 7
2015 Vithana CL, Sullivan LA, Bush RT, Burton ED, 'Schwertmannite in soil materials: Limits of detection of acidified ammonium oxalate method and differential X-ray diffraction', Geoderma, 249-250 51-60 (2015) [C1]

© 2015 Elsevier B.V. Schwertmannite is a secondary iron mineral, found in acid mine drainage (AMD) and acid sulfate soils (ASS), that generates acidity when it transforms to stabl... [more]

© 2015 Elsevier B.V. Schwertmannite is a secondary iron mineral, found in acid mine drainage (AMD) and acid sulfate soils (ASS), that generates acidity when it transforms to stable mineral phases. Acidity liberated during schwertmannite transformation can seriously diminish water quality and soil health. Acidified ammonium oxalate (AAO) extraction in the dark coupled with differential X-ray diffraction (DXRD) analysis is routinely used to identify and to quantify poorly crystalline iron oxide phases such as schwertmannite in AMD environments. However, management of ASS environments is largely impacted due to lack of reliable methods to identify/quantify schwertmannite in soil materials. Our study aimed to evaluate the 15. min AAO extraction method to identify/quantify schwertmannite in soil materials. We extracted soil samples spiked with synthetic and natural schwertmannite (termed as natural organic rich schwertmannitic material) with acidified ammonium oxalate (AAO) for 15. min. We also examined soil samples spiked with schwertmannite through the DXRD analysis under ideal conditions assuming that only schwertmannite would dissolve during the extraction. Our data show that synthetic schwertmannite dissolved partially during the 15. min AAO extraction and as a result the recovered Fe content from schwertmannite-spiked soils was underestimated by ~. 20%. The data also show that soil materials could also influence the recovery of schwertmannite. Fe/S molar ratios of schwertmannite spiked at higher rates (2% and 5%) were closer to the expected ratios. In addition to schwertmannite, goethite and other unidentified minerals in natural organic rich schwertmannitic material also dissolved during the 15. min extraction time. The DXRD analysis data show that schwertmannite in soil materials at contents >. 5% may be identifiable through this approach. Our findings highlight that both the 15. min AAO extraction procedure and the DXRD analysis have limited applicability towards detecting schwertmannite accurately in soil materials.

DOI 10.1016/j.geoderma.2015.03.004
Citations Scopus - 3
2015 Li S, Bush RT, 'Rising flux of nutrients (C, N, P and Si) in the lower Mekong River', Journal of Hydrology, 530 447-461 (2015) [C1]

© 2015 Elsevier B.V. Changing human land use is accelerating global element cycling and appreciably altering ecosystems in the riverine-estuarine systems. This is evident by drama... [more]

© 2015 Elsevier B.V. Changing human land use is accelerating global element cycling and appreciably altering ecosystems in the riverine-estuarine systems. This is evident by dramatic shifts in the supply of nutrients (C, N, P, Si). However, very little is known about the magnitude and rates of these changes. We examine the Mekong, one of the world largest rivers, to assess on a whole-of-system scale, the spatial, monthly and inter-annual flux of nutrients and stoichiometric ratios using a huge data-set (1985-2011). Seasonal and spatial patterns are apparent and linked to hydrology. The estimated mean flux (×109mol/y) of elements from the Mekong at Pakse are 414.5 for DIC, 4.1 for DIN (3.3 for NO3--N and 0.8 for NH4+-N), 10.2 for TN, 0.32 for DIP, 0.46 for TP and 62.8 for DSi, respectively, which are intermediate relative to other large rivers. However, compared to the river reach at Pakse, the total river fluxes are two-fold greater for C, N, P and DSi. Annual flux increases significantly for DIC, NO3--N, DIN, TN and DSi, and is especially pronounced for all N and P species during the recent decade (1998 onward). Distinct shifts of nutrient stoichiometry, with far-reaching changes for phytoplankton productivity in the Mekong estuary are also evident, as the system shifts from potentially N limited to P limited. These notable changes to the exports and ratios of nutrient variables and anthropogenically-driven nutrient concerns are becoming a defining feature of the Mekong Plume to the South China Sea.

DOI 10.1016/j.jhydrol.2015.10.005
Citations Scopus - 6
2015 Li S, Zhang Q, Bush RT, Sullivan LA, 'Methane and CO

© 2015, Springer-Verlag Berlin Heidelberg. Controversy surrounds the green credentials of hydroelectricity because of the potentially large emission of greenhouse gases (GHG) from... [more]

© 2015, Springer-Verlag Berlin Heidelberg. Controversy surrounds the green credentials of hydroelectricity because of the potentially large emission of greenhouse gases (GHG) from associated reservoirs. However, limited and patchy data particularly for China is constraining the current global assessment of GHG releases from hydroelectric reservoirs. This study provides the first evaluation of the CO2and CH4emissions from China¿s hydroelectric reservoirs by considering the reservoir water surface and drawdown areas, and downstream sources (including spillways and turbines, as well as river downstream). The total emission of 29.6¿Tg CO2/year and 0.47¿Tg CH4/year from hydroelectric reservoirs in China, expressed as CO2equivalents (eq), corresponds to 45.6¿Tg CO2eq/year, which is 2-fold higher than the current GHG emission (ca. 23¿Tg CO2eq/year) from global temperate hydropower reservoirs. China¿s average emission of 70¿g CO2eq/kWh from hydropower amounts to 7¿% of the emissions from coal-fired plant alternatives. China¿s hydroelectric reservoirs thus currently mitigate GHG emission when compared to the main alternative source of electricity with potentially far great reductions in GHG emissions and benefits possible through relatively minor changes to reservoir management and design. On average, the sum of drawdown and downstream emission including river reaches below dams and turbines, which is overlooked by most studies, represents the equivalent of 42¿% of the CO2and 92¿% of CH4that emit from hydroelectric reservoirs in China. Main drivers on GHG emission rates are summarized and highlight that water depth and stratification control CH4flux, and CO2flux shows significant negative relationships with pH, DO, and Chl-a. Based on our finding, a substantial revision of the global carbon emissions from hydroelectric reservoirs is warranted.

DOI 10.1007/s11356-015-4083-9
Citations Scopus - 11
2015 Li S, Bush RT, 'Revision of methane and carbon dioxide emissions from inland waters in India', Global Change Biology, 21 6-8 (2015)
DOI 10.1111/gcb.12705
Citations Scopus - 10
2015 Ling YC, Bush R, Grice K, Tulipani S, Berwick L, Moreau JW, 'Distribution of iron- and sulfate-reducing bacteria across a coastal acid sulfate soil (CASS) environment: Implications for passive bioremediation by tidal inundation', Frontiers in Microbiology, 6 (2015)

© 2015 Ling, Bush, Grice, Tulipani, Berwick and Moreau. Coastal acid sulfate soils (CASS) constitute a serious and global environmental problem. Oxidation of iron sulfide minerals... [more]

© 2015 Ling, Bush, Grice, Tulipani, Berwick and Moreau. Coastal acid sulfate soils (CASS) constitute a serious and global environmental problem. Oxidation of iron sulfide minerals exposed to air generates sulfuric acid with consequently negative impacts on coastal and estuarine ecosystems. Tidal inundation represents one current treatment strategy for CASS, with the aim of neutralizing acidity by triggering microbial iron- and sulfate-reduction and inducing the precipitation of iron-sulfides. Although well-known functional guilds of bacteria drive these processes, their distributions within CASS environments, as well as their relationships to tidal cycling and the availability of nutrients and electron acceptors, are poorly understood. These factors will determine the long-term efficacy of "passive" CASS remediation strategies. Here we studied microbial community structure and functional guild distribution in sediment cores obtained from 10 depths ranging from 0 to 20 cm in three sites located in the supra-, inter- and sub-tidal segments, respectively, of a CASS-affected salt marsh (East Trinity, Cairns, Australia). Whole community 16S rRNA gene diversity within each site was assessed by 454 pyrotag sequencing and bioinformatic analyses in the context of local hydrological, geochemical, and lithological factors. The results illustrate spatial overlap, or close association, of iron-, and sulfate-reducing bacteria (SRB) in an environment rich in organic matter and controlled by parameters such as acidity, redox potential, degree of water saturation, and mineralization. The observed spatial distribution implies the need for empirical understanding of the timing, relative to tidal cycling, of various terminal electron-accepting processes that control acid generation and biogeochemical iron and sulfur cycling.

DOI 10.3389/fmicb.2015.00624
Citations Scopus - 7
2015 Li S, Bush RT, 'Changing fluxes of carbon and other solutes from the Mekong River', Scientific Reports, 5 (2015)

Rivers are an important aquatic conduit that connects terrestrial sources of dissolved inorganic carbon (DIC) and other elements with oceanic reservoirs. The Mekong River, one of ... [more]

Rivers are an important aquatic conduit that connects terrestrial sources of dissolved inorganic carbon (DIC) and other elements with oceanic reservoirs. The Mekong River, one of the worlds largest rivers, is firstly examined to explore inter-annual fluxes of dissolved and particulate constituents during 1923-2011 and their associated natural or anthropogenic controls. Over this period, inter-annual fluxes of dissolved and particulate constituents decrease, while anthropogenic activities have doubled the relative abundance of SO 4 2-', Cl -' and Na +. The estimated fluxes of solutes from the Mekong decrease as follows (Mt/y): TDS (40.4) > HCO 3 -' (23.4) > Ca 2+ (6.4) > SO 4 2-' (3.8) > Cl -' (1.74)~Na + (1.7) ~ Si (1.67) > Mg 2+ (1.2) > K + (0.5). The runoff, land cover and lithological composition significantly contribute to dissolved and particulate yields globally. HCO 3 -' and TDS yields are readily predicted by runoff and percent of carbonate, while TSS yield by runoff and population density. The Himalayan Rivers, including the Mekong, are a disproportionally high contributor to global riverine carbon and other solute budgets, and are of course underlined. The estimated global riverine HCO 3 -' flux (Himalayan Rivers included) is 34014 × 10 9 mol/y (0.41 Pg C/y), 3915 Mt/y for solute load, including HCO 3 -', and 13553 Mt/y for TSS. Thereby this study illustrates the importance of riverine solute delivery in global carbon cycling.

DOI 10.1038/srep16005
Citations Scopus - 12
2014 Wang Z, Bush RT, Sullivan LA, Chen C, Liu J, 'Selective oxidation of arsenite by peroxymonosulfate with high utilization efficiency of oxidant', Environmental Science and Technology, 48 3978-3985 (2014) [C1]

Oxidation of arsenite (As(III)) is a critical yet often weak link in many current technologies for remediating contaminated groundwater. We report a novel, efficient oxidation rea... [more]

Oxidation of arsenite (As(III)) is a critical yet often weak link in many current technologies for remediating contaminated groundwater. We report a novel, efficient oxidation reaction for As(III) conversion to As(V) using commercial available peroxymonosulfate (PMS). As(III) is rapidly oxidized by PMS with a utilization efficiency larger than 90%. Increasing PMS concentrations and pH accelerate oxidation of As(III), independent to the availability of dissolved oxygen the addition of PMS enables As(III) to oxidize completely to As(V) within 24 h, even in the presence of high concentrations of radical scavengers. On the basis of these observations and theoretical calculations, a two-electron transfer (i.e., oxygen atom transfer) reaction pathway is proposed. Direct oxidation of As(III) by PMS avoids the formation of nonselective reactive radicals, thus minimizing the adverse impact of coexisting organic matter and maximizing the utilization efficiency of PMS therefore, this simple approach is considered a cost-effective water treatment method for the oxidation of As(III) to As(V). © 2014 American Chemical Society.

DOI 10.1021/es405143u
Citations Scopus - 36Web of Science - 31
Co-authors Zhaohui Wang
2014 Keene AF, Johnston SG, Bush RT, Burton ED, Sullivan LA, Dundon M, et al., 'Enrichment and heterogeneity of trace elements at the redox-interface of Fe-rich intertidal sediments', Chemical Geology, 383 1-12 (2014)

Redox-interfacial sediments can undergo radical geochemical changes with oscillating tides. In this study, we examine trace element enrichment and availability, at both landscape ... [more]

Redox-interfacial sediments can undergo radical geochemical changes with oscillating tides. In this study, we examine trace element enrichment and availability, at both landscape and pedon-scales, in the surface sediments of a remediating acidic tidal wetland. Fe-rich sediments at the surface-water interface (0-10. mm in depth) were collected across an elevation gradient spanning the supratidal to subtidal range. These sediments were analysed for solid phase Fe fractions and trace elements (As, Pb, Cr, Cu, Mn, Ni, Zn, V, B, Co, Mo, Ba and U) via dilute HCl-extractions and total digests. Their concentrations were compared with those of underlying (0.05-0.65. m in depth) former sulfuric horizon sediments of a coastal acid sulfate soil (CASS). Reactive Fe was enriched at the redox interface by up to 16 times (197. g. Fe/kg) that of the former sulfuric horizon. The proportion of total trace elements associated with reactive phases was high in interfacial sediments, representing over 90% of B and U and 50% of Pb, Cu, Zn, V and Ba extractable by dilute HCl. The interfacial sediments were particularly enriched in reactive Cr, Cu, Ni, Zn, B, Mo and U, with reactive B, Mo and U concentrations between 5 and 10 times greater than in the former sulfuric horizon. Surface enrichment of trace elements is strongly co-associated with Fe(III) mineralisation, likely via sorption and co-precipitation processes. Enrichment is highly spatially heterogeneous and is strongly influenced by elevation and tidal zonation at a landscape-scale and by sediment micro-topography and preferential advective transport via surface connected macropores at the pedon-scale. The results from this study provide new insights to the processes influencing trace element enrichment in Fe-rich redox-interfacial sediments across a remediating acidic tidal wetland. © 2014 Elsevier B.V.

DOI 10.1016/j.chemgeo.2014.06.003
Citations Scopus - 7
2014 Vithana CL, Sullivan LA, Burton ED, Bush RT, 'Liberation of acidity and arsenic from schwertmannite: Effect of fulvic acid', Chemical Geology, 372 1-11 (2014)

Schwertmannite is one of the major components that produces acidity in acid mine drainage (AMD) and acid sulfate soils (ASS) and is also known to be an effective scavenger of Arse... [more]

Schwertmannite is one of the major components that produces acidity in acid mine drainage (AMD) and acid sulfate soils (ASS) and is also known to be an effective scavenger of Arsenic (As) in such environments. Fulvic acid (FA) is an active component of natural organic matter (NOM) and is known to interact strongly with both schwertmannite and As. Two main environmental hazards related to schwertmannite are acidity liberation and potential re-mobilization of adsorbed or co-precipitated As upon hydrolysis. This study focused on understanding the behaviour of As-substituted schwertmannite with regard to the potential of acidity liberation, the effect of FA on acidity liberation from both pure and As-substituted synthetic schwertmannites, and the effect of FA on arsenic mobilization from As-substituted synthetic schwertmannite. This was investigated by means of short-term (48. h) titrations. The liberation of acidity from As-substituted schwertmannite and the effect of FA were examined at two pH values (i.e. 4.5 and 6.5) typical for ASS environments.As-substituted schwertmannite liberated a greater amount of acidity in comparison to pure schwertmannite at both pHs. Concentration of FA and pH each showed a strong influence on the liberation of acidity from both pure and As-schwertmannite. At the acidic pH (4.5), FA inhibited acidity liberation from schwertmannite. At the near neutral pH of 6.5, the concentration of FA played a critical role in affecting the liberation of acidity from schwertmannite. The initial liberation of acidity was enhanced from pure schwertmannite at pH6.5 by low FA concentration (1mgL-1) and from As-schwertmannite by both low (1mgL-1) and moderate (10mgL-1) FA concentrations. Interestingly, higher FA concentrations (25mgL-1) inhibited acidity liberation from both types of schwertmannite in comparison to the control (pure/As-schwertmannite titrated without added FA). FA enhanced the liberation of As from the As-schwertmannite at both pHs under oxidising conditions and the rate of As liberation was greater at the near neutral pH. The present study provides new insights on the effect of As-substitution on acidity liberation from schwertmannite and the role of FA on: a) liberation of acidity, and b) As mobilization, from schwertmannite. © 2014.

DOI 10.1016/j.chemgeo.2014.02.012
Citations Scopus - 8
2014 Li S, Lu XX, Bush RT, 'Chemical weathering and CO

Data on river water quality from 42 monitoring stations in the Lower Mekong Basin obtained during the period 1972-1996 was used to relate solute fluxes with controlling factors su... [more]

Data on river water quality from 42 monitoring stations in the Lower Mekong Basin obtained during the period 1972-1996 was used to relate solute fluxes with controlling factors such as chemical weathering processes. The total dissolved solid (TDS) concentration of the Lower Mekong varied from 53mg/L to 198mg/L, and the median (114mg/L) was compared to the world spatial median value (127mg/L). Total cationic exchange capacity (Tz+) ranged from 729 to 2607µmolc/L, and the mean (1572µmolc/L) was 1.4 times higher than the world discharge-weighted average. Calcium and bicarbonate dominated the annual ionic composition, accounting for ~70% of the solute load that equalled 41.2×109kg/y. TDS and major elements varied seasonally and in a predictable way with river runoff. The chemical weathering rate of 37.7t/(km2y), with respective carbonate and silicate weathering rates of 27.5t/(km2y) (13.8mm/ky) and 10.2t/(km2y) (3.8mm/ky), was 1.5 times higher than the global average. The CO2consumption rate was estimated at 191×103molCO2/(km2y) for silicate weathering, and 286×103molCO2/(km2y) by carbonate weathering. In total, the Mekong basin consumed 228×109molCO2/y and 152×109molCO2/y by the combined weathering of carbonate and silicate, constituting 1.85% of the global CO2consumption by carbonate weathering and 1.75% by silicates. This is marginally higher than its contribution to global water discharge ~1.3% and much higher than (more than three-fold) its contribution to world land surface area. Remarkable CO2consumed by chemical weathering (380×109mol/y) was similar in magnitude to dissolved inorganic carbon as HCO3-(370×109mol/y) exported by the Mekong to the South China Sea. In this landscape, atmospheric CO2consumption by rock chemical weathering represents an important carbon sink with runoff and physical erosion controlling chemical erosion. © 2013 Elsevier B.V.

DOI 10.1016/j.scitotenv.2013.11.027
Citations Scopus - 19
2014 Vithana CL, Sullivan LA, Bush RT, Burton ED, 'Jarosite quantification in soils: An enhanced sequential extraction procedure', Applied Geochemistry, 51 130-138 (2014)

© 2014 Elsevier Ltd. A two-step sequential extraction procedure established for the quantification of acidity producing ferric and ferrous sulfate minerals such as melanterite and... [more]

© 2014 Elsevier Ltd. A two-step sequential extraction procedure established for the quantification of acidity producing ferric and ferrous sulfate minerals such as melanterite and jarosite in acid mine wastes was evaluated for quantification of jarosite spiked in soils. The procedure involves in sequence anoxic water extraction, roasting the solid residue after anoxic water extraction at 550. °C for 1. h, and 4. M HCl extraction of the roasted solid. Soil and quartz samples were spiked with known amounts of synthetic and natural jarosite and their recovery was measured using the suggested two-step sequential extraction procedure. The recoveries of synthetic and natural jarosite were calculated on the basis of the S contents of the initially spiked jarosite in soil and quartz samples. Less than 50% of the spiked jarosite was recovered. The missing S is partially attributable to the retention of jarosite by the Teflon filter membrane used during the filtration of the anoxic water extract. Further investigations also demonstrated a lower 4. M HCl-S extractability from jarosite samples roasted at 550. °C than those roasted at 450. °C. S recovery from jarosite-spiked quartz samples increased to 45-70% by replacing the Teflon filter membrane with the Cellulose Acetate filter membrane and including this filter paper in the second step roasting. This modified method is a step forward in the development of methods to accurately and reliably quantify jarosite in soil materials.

DOI 10.1016/j.apgeochem.2014.10.006
2013 Wang Z, Bush RT, Sullivan LA, Liu J, 'Simultaneous redox conversion of chromium(VI) and arsenic(III) under acidic conditions', Environmental Science and Technology, 47 6486-6492 (2013) [C1]

Arsenic and chromium are often abundant constituents of acid mine drainage (AMD) and are most harmful as arsenite (As(III)) and hexavalent (Cr(VI)). To simultaneously change their... [more]

Arsenic and chromium are often abundant constituents of acid mine drainage (AMD) and are most harmful as arsenite (As(III)) and hexavalent (Cr(VI)). To simultaneously change their oxidation state from As(III) to As(V), and Cr(VI) to Cr(III), is a potentially effective and attractive strategy for environmental remediation. The coabundance of As(III) and Cr(VI) in natural environments indicates their negligible direct interaction. The addition of H 2O2 enables and greatly accelerates the simultaneous oxidation of As(III) and reduction of Cr(VI). These reactions are further enhanced at acidic pH and higher concentrations of Cr(VI). However, the presence of ligands (i.e., oxalate, citrate, pyrophosphate) greatly retards the oxidation of As(III), even though it enhances the reduction of Cr(VI). To explain these results we propose a reaction mechanism where Cr(VI) is primarily reduced to Cr(III) by H2O2, via the intermediate tetraperoxochromate Cr(V). Cr(V) is then involved in the formation of ¿OH radicals. In the presence of ligands, the capacity of Cr(V) to form ¿OH radicals, which are primarily responsible for As(III) oxidation, is practically inhibited. Our findings demonstrate the feasibility for the coconversion of As(III) and Cr(VI) in AMD and real-world constraints to this strategy for environmental remediation. © 2013 American Chemical Society.

DOI 10.1021/es400547p
Citations Scopus - 34Web of Science - 33
Co-authors Zhaohui Wang
2013 Wang Z, Bush RT, Liu J, 'Arsenic(III) and iron(II) co-oxidation by oxygen and hydrogen peroxide: Divergent reactions in the presence of organic ligands', Chemosphere, 93 1936-1941 (2013) [C1]

Iron-catalyzed oxidation of As(III) to As(V) can be highly effective for toxic arsenic removal via Fenton reaction and Fe(II) oxygenation. However, the contribution of ubiquitous ... [more]

Iron-catalyzed oxidation of As(III) to As(V) can be highly effective for toxic arsenic removal via Fenton reaction and Fe(II) oxygenation. However, the contribution of ubiquitous organic ligands is poorly understood, despite its significant role in redox chemistry of arsenic in natural and engineered systems. In this work, selected naturally occurring organic ligands and synthetic ligands in co-oxidation of Fe(II) and As(III) were examined as a function of pH, Fe(II), H2O2, and radical scavengers (methanol and 2-propanol) concentration. As(III) was not measurably oxidised in the presence of excess ethylenediaminetetraacetic acid (EDTA) (i.e. Fe(II):EDTA<1:1), contrasting with the rapid oxidation of Fe(II) by O2 and H2O2 at neutral pH under the same conditions. However, partial oxidation of As(III) was observed at a 2:1 ratio of Fe(II):EDTA. Rapid Fe(II) oxidation in the presence of organic ligands did not necessarily result in the coupled As(III) oxidation. Organic ligands act as both iron speciation regulators and radicals scavengers. Further quenching experiments suggested both hydroxyl radicals and high-valent Fe species contributed to As(III) oxidation. The present findings are significant for the better understanding of aquatic redox chemistry of iron and arsenic in the environment and for optimization of iron-catalyzed arsenic remediation technology. © 2013 Elsevier Ltd.

DOI 10.1016/j.chemosphere.2013.06.076
Citations Scopus - 13Web of Science - 12
Co-authors Zhaohui Wang
2013 Burton ED, Johnston SG, Kraal P, Bush RT, Claff S, 'Sulfate availability drives divergent evolution of arsenic speciation during microbially mediated reductive transformation of schwertmannite', Environmental Science and Technology, 47 2221-2229 (2013) [C1]

The effect of SO42- availability on the microbially mediated reductive transformation of As(V)-coprecipitated schwertmannite (Fe8O8(OH)3.2(SO4) 2.4(AsO4)0.004) was examined in lon... [more]

The effect of SO42- availability on the microbially mediated reductive transformation of As(V)-coprecipitated schwertmannite (Fe8O8(OH)3.2(SO4) 2.4(AsO4)0.004) was examined in long-term (up to 400 days) incubation experiments. Iron EXAFS spectroscopy showed siderite (FeCO3) and mackinawite (FeS) were the dominant secondary Fe(II) minerals produced via reductive schwertmannite transformation. In addition, ~25% to ~65% of the initial schwertmannite was also transformed relatively rapidly to goethite (aFeOOH), with the extent of this transformation being dependent on SO42- concentrations. More specifically, the presence of high SO42- concentrations acted to stabilize schwertmannite, retarding its transformation to goethite and allowing its partial persistence over the 400 day experiment duration. Elevated SO42- also decreased the extent of dissimilatory reduction of Fe(III) and As(V), instead favoring dissimilatory SO42- reduction. In contrast, where SO42- was less available, there was near-complete reduction of schwertmannite- and goethite-derived Fe(III) as well as solid-phase As(V). As a result, under low SO42- conditions, almost no Fe(III) or As(V) remained toward the end of the experiment and arsenic solid-phase partitioning was controlled mainly by sorptive interactions between As(III) and mackinawite. These As(III)-mackinawite interactions led to the formation of an orpiment (As2S3)-like species. Interestingly, this orpiment-like arsenic species did not form under SO42--rich conditions, despite the prevalence of dissimilatory SO 42- reduction. The absence of an arsenic sulfide species under SO42--rich conditions appears to have been a consequence of schwertmannite persistence, combined with the preferential retention of arsenic oxyanions by schwertmannite. The results highlight the critical role that SO42- availability can play in controlling solid-phase arsenic speciation, particularly arsenic-sulfur interactions, under reducing conditions in soils, sediments, and shallow groundwater systems. © 2013 American Chemical Society.

DOI 10.1021/es303867t
Citations Scopus - 36
2013 Kraal P, Burton ED, Rose AL, Cheetham MD, Bush RT, Sullivan LA, 'Decoupling between water column oxygenation and benthic phosphate dynamics in a shallow eutrophic estuary', Environmental Science and Technology, 47 3114-3121 (2013) [C1]

Estuaries are crucial biogeochemical filters at the land-ocean interface that are strongly impacted by anthropogenic nutrient inputs. Here, we investigate benthic nitrogen (N) and... [more]

Estuaries are crucial biogeochemical filters at the land-ocean interface that are strongly impacted by anthropogenic nutrient inputs. Here, we investigate benthic nitrogen (N) and phosphorus (P) dynamics in relation to physicochemical surface sediment properties and bottom water mixing in the shallow, eutrophic Peel-Harvey Estuary. Our results show the strong dependence of sedimentary P release on Fe and S redox cycling. The estuary contains surface sediments that are strongly reducing and act as net P source, despite physical sediment mixing under an oxygenated water column. This decoupling between water column oxygenation and benthic P dynamics is of great importance to understand the evolution of nutrient dynamics in marine systems in response to increasing nutrient loadings. In addition, the findings show that the relationship between P burial efficiency and bottom water oxygenation depends on local conditions; sediment properties rather than oxygen availability may control benthic P recycling. Overall, our results illustrate the complex response of an estuary to environmental change because of interacting physical and biogeochemical processes. © 2013 American Chemical Society.

DOI 10.1021/es304868t
Citations Scopus - 17
2013 Kraal P, Burton ED, Bush RT, 'Iron monosulfide accumulation and pyrite formation in eutrophic estuarine sediments', Geochimica et Cosmochimica Acta, 122 75-88 (2013)

This study investigates iron (Fe) and sulfur (S) cycling in sediments from the eutrophic Peel-Harvey Estuary in Western Australia, which is subject to localized accumulation of st... [more]

This study investigates iron (Fe) and sulfur (S) cycling in sediments from the eutrophic Peel-Harvey Estuary in Western Australia, which is subject to localized accumulation of strongly reducing, organic- and sulfide-rich sediments. Sedimentary iron was mostly present in highly reactive form (on average 73% of total Fe) and showed extensive sulfidization even in surface sediments, despite being overlain by a well-mixed oxygenated water column. This indicates that, under eutrophic marine conditions, Fe sulfidization may be driven by reductive processes in the sediment without requiring oxygen depletion in the overlying waters. Strong enrichments in iron monosulfide (FeS>300µmolg-1) were observed in fine-grained sediment intervals up to 45cm depth. This metastable Fe sulfide is commonly restricted to thin subsurface sediment intervals, below which pyrite (FeS2) dominates. Our findings suggest inhibition of the dissolution-precipitation processes that replace FeS with FeS2in sediments. Rates of pyrite formation based on the FeS2profiles were much lower than those predicted by applying commonly used kinetic equations for pyrite formation. Dissolved H2S was present at millimolar levels throughout the investigated sediment profiles. This may indicate that (i) pyrite formation via reaction between dissolved Fe (including Fe clusters) and H2S was limited by low availability of dissolved Fe or (ii) reaction kinetics of pyrite formation via the H2S pathway may be relatively slow in natural reducing sediments. We propose that rapid burial of the FeS under anoxic conditions in these organic-rich reducing sediments minimizes the potential for pyrite formation, possibly by preventing dissolution of FeS or by limiting the availability of oxidized sulfur species that are required for pyrite formation via the polysulfide pathway. © 2013 Elsevier Ltd.

DOI 10.1016/j.gca.2013.08.013
Citations Scopus - 37
2013 Li S, Lu XX, Bush RT, 'CO

CO2evasion from freshwaters is recently included in assessing global carbon budgets, while large uncertainty of global estimates results from incomplete spatial coverage of aquati... [more]

CO2evasion from freshwaters is recently included in assessing global carbon budgets, while large uncertainty of global estimates results from incomplete spatial coverage of aquatic carbon emission. Here we examined the dissolved inorganic carbon (DIC) and carbon dioxide partial pressure (pCO2) in riverine water from historical records at 46 stations for the period 1972-1998 in the Lower Mekong River (LMR). The river system presented an exceptional temporal and spatial variability of dissolved inorganic carbon (DIC) species. The alkalinity concentration of the LMR varied from 687 to 3189µeq/l with an average of 1524µeq/l (median value: 1586µeq/l), 1.2 times the global median value. Spatial patterns showed diminishing alkalinity downstream at the main-channel stations along the LMR. Similar to many other Himalayan rivers, alkalinity varied seasonally and inversely related to river runoff with a variation factor of 1.2-1.6, despite a water dilution of 7-fold to 13-fold in the summer flood season. The pCO2levels ranged from 224 to 5970µatm with a total average of 1090µatm and obvious monthly and spatial variations. Under-saturated pCO2samples (<390µatm) primarily occurred in the high-flow period. pCO2at the main-channel stations increased downstream and averaged from 720µatm (Mukdahan) to 1670µatm (Can Tho). Calculated water-to-air CO2degassing from the Mekong River was 71mol/m2/yr, thus 6.8Tg C/yr as CO2was released to the atmosphere, 1.5-fold the sea-ward DIC export (4.5Tg C/yr). Basin characteristics influences on pCO2from 25 global rivers demonstrated that non-carbonate rocks significantly contributed to pCO2, population density, agricultural practices, elevation and slope decreased pCO2, while forest significantly increased pCO2. Our results demonstrated the essential need to consider river water area as an essential atmospheric CO2source, albeit this atmospheric flux, representing significant riverine carbon budgets, was highly variable at temporal and spatial scales. © 2013 Elsevier B.V.

DOI 10.1016/j.jhydrol.2013.09.024
Citations Scopus - 35
2013 Wong VNL, Johnston SG, Burton ED, Bush RT, Sullivan LA, Slavich PG, 'Seawater-induced mobilization of trace metals from mackinawite-rich estuarine sediments', Water Research, 47 821-832 (2013) [C1]

Benthic sediments in coastal acid sulfate soil (CASS) drains can contain high concentrations (~1-5%) of acid volatile sulfide (AVS) as nano-particulate mackinawite. These sediment... [more]

Benthic sediments in coastal acid sulfate soil (CASS) drains can contain high concentrations (~1-5%) of acid volatile sulfide (AVS) as nano-particulate mackinawite. These sediments can sequester substantial quantities of trace metals. Because of their low elevation and the connectivity of drains to estuarine channels, these benthic sediments are vulnerable to rapid increases in ionic strength from seawater incursion by floodgate opening, floodgate failure, storm surge and seasonal migration of the estuarine salt wedge. This study examines the effect of increasing seawater concentration on trace metal mobilization from mackinawite-rich drain sediments (210-550 µmol g-1AVS) collected along an estuarine salinity gradient. Linear combination fitting of S K-edge XANES indicated mackinawite comprised 88-96% of sediment-bound S. Anoxic sediment suspensions were conducted with seawater concentrations ranging from 0% to 100%. We found that mobilization of some metals increased markedly with increasing ionic strength (Cu, Fe, Mn, Ni) whereas Al mobilization decreased. The largest proportion of metals mobilized from the labile metal pool, operationally defined as ¿exchangeable + acid-extractable + organically-bound metals, occurred in sediments from relatively fresh upstream sites (up to 39% mobilized) compared to sediments sourced from brackish downstream sites (0-11% mobilized). The extent of relative trace metal desorption generally followed the sequence Mn > Ni ¿ Cu > Zn > Fe > Al. Trace metal mobilization from these mackinawite-rich sediments was attributed primarily to desorption of weakly-bound metals via competitive exchange with marine-derived cations and enhanced complexation with Cl-and dissolved organic ligands. These results have important implications for trace metal mobilization from these sediments at near-neutral pH under current predicted sea-level rise and climate change scenarios. © 2012 Elsevier Ltd.

DOI 10.1016/j.watres.2012.11.009
Citations Scopus - 12
2013 Lockhart RS, Berwick LJ, Greenwood P, Grice K, Kraal P, Bush R, 'Analytical pyrolysis for determining the molecular composition of contemporary monosulfidic black ooze', Journal of Analytical and Applied Pyrolysis, 104 640-652 (2013)

On-line flash pyrolysis, micro-scale sealed vessel (MSSV) pyrolysis and catalytic hydropyrolysis (HyPy) were used to characterise the insoluble, macromolecular organic component o... [more]

On-line flash pyrolysis, micro-scale sealed vessel (MSSV) pyrolysis and catalytic hydropyrolysis (HyPy) were used to characterise the insoluble, macromolecular organic component of monosulfidic black oozes (MBO) which have accumulated within the contemporary eutrophic environment of the Peel-Harvey estuary system (Geographe Bay, Western Australia). Pyrolysates were analysed by gas chromatography-mass spectrometry (GC-MS) and the relative characterisation potential of the three pyrolysis techniques were evaluated with a particular interest in their sensitivity to organic sulfur compounds (OSCs). A similarity of results obtained from three different parts of the ~1 m cores sampled suggests a largely homogenous organic composition throughout the unit. The different pyrolysis techniques did, however, show several notable product differences, particularly the gaseous products detected by the on-line methods of flash- and MSSV-pyrolysis. The very high (i.e., ballistic) heating rate of flash-Py produced very high proportions of gaseous products (e.g., CO2, H2S and SO2). A strong terrestrially sourced product component was reflected in all three pyrolysates profiles: flash-Py showed relatively high concentrations of lignocellulose products, while MSSV-Py and HyPy produced an abundance of plant wax (>n-C20) n-alkanes. Additionally, quantitatively significant levels (7-14% of total GC product signal) of several higher plant derived terpenoids (e.g., cadalene, p-cymene and calamanene) were identified by MSSV-Py. MSSV-Py also produced far greater overall concentrations of GC-amenable products than flash-Py, including a 14-fold increase of OSCs, which comprised nearly 10% of the total sulfur signal (i.e., organic plus 'inorganic' sulfur; cf. 4% of flash pyrolysis). An extended series of alkyl (<C9) substituted thiophenes were the main OSCs. HyPy, in contrast, showed no evidence of OSCs - confirmed by GC-flame photometric detection (FPD). HyPy is renowned for its capacity to preserve primary structural units, so its failure to detect thiophenes and other OSCs abundant in the corresponding analysis, suggests these are not indigenous to the macromolecular fraction of the MBO. The detection of these products by MSSV-Py, and to a lesser extent flash-Py, suggests these pyrolysis methods initiate a restructuring of sulfur species towards more thermally stable secondary configurations. One explanation for the limited diagnostic S-speciation data obtained from the present analysis may be the existence of most of the S in the MBO as bridging units between covalently bound organic structures. These relatively weakly bound associations may form on the reaction of reduced sulfur species (from bacterial sulfate reduction) with highly functionalised organic compounds during the early stages of diagenesis. © 2013 Elsevier B.V. All rights reserved.

DOI 10.1016/j.jaap.2013.05.002
Citations Scopus - 6
2013 Vithana CL, Sullivan LA, Bush RT, Burton ED, 'Acidity fractions in acid sulfate soils and sediments: Contributions of schwertmannite and jarosite', Soil Research, 51 203-214 (2013) [C1]

In Australia, the assessment of acidity hazard in acid sulfate soils requires the estimation of operationally defined acidity fractions such as actual acidity, potential sulfidic ... [more]

In Australia, the assessment of acidity hazard in acid sulfate soils requires the estimation of operationally defined acidity fractions such as actual acidity, potential sulfidic acidity, and retained acidity. Acid-base accounting approaches in Australia use these acidity fractions to estimate the net acidity of acid sulfate soils materials. Retained acidity is the acidity stored in the secondary Fe/Al hydroxy sulfate minerals, such as jarosite, natrojarosite, schwertmannite, and basaluminite. Retained acidity is usually measured as either net acid-soluble sulfur (SNAS) or residual acid soluble sulfur (SRAS). In the present study, contributions of schwertmannite and jarosite to the retained acidity, actual acidity, and potential sulfidic acidity fractions were systematically evaluated using S NAS and SRAS techniques. The data show that schwertmannite contributed considerably to the actual acidity fraction and that it does not contribute solely to the retained acidity fraction as has been previously conceptualised. As a consequence, SNAS values greatly underestimated the schwertmannite content. For soil samples in which jarosite is the only mineral present, a better estimate of the added jarosite content can be obtained by using a correction factor of 2 to SNAS values to account for the observed 50-60% recovery. Further work on a broader range of jarosite samples is needed to determine whether this correction factor has broad applicability. The SRAS was unable to reliably quantify either the schwertmannite or the jarosite content and, therefore, is not suitable for quantification of the retained acidity fraction. Potential sulfidic acidity in acid sulfate soils is conceptually derived from reduced inorganic sulfur minerals and has been estimated by the peroxide oxidation approach, which is used to derive the S RAS values. However, both schwertmannite and jarosite contributed to the peroxide-oxidisable sulfur fraction, implying a major potential interference by those two minerals to the determination of potential sulfidic acidity in acid sulfate soils through the peroxide oxidation approach. © 2013 CSIRO.

DOI 10.1071/SR12291
Citations Scopus - 9
2012 Erskine WD, Keene A, Bush R, Cheetham M, Chalmers AC, 'Influence of riparian vegetation on channel widening and subsequent contraction on a sand-bed stream since European settlement: Widden Brook, Australia', Geomorphology, 147-148 102-114 (2012) [C1]
Citations Scopus - 19Web of Science - 22
Co-authors Anita Chalmers
2012 Johnston SG, Keene AF, Burton ED, Bush RT, Sullivan LA, 'Quantifying alkalinity generating processes in a tidally remediating acidic wetland', Chemical Geology, 304-305 106-116 (2012)

Lime-assisted tidal exchange (LATE) is a new remediation technique that is demonstrably effective at decreasing acidity in coastal acid sulfate soils (CASS). However, the relative... [more]

Lime-assisted tidal exchange (LATE) is a new remediation technique that is demonstrably effective at decreasing acidity in coastal acid sulfate soils (CASS). However, the relative magnitude of the major in situ alkalinity generating processes and external alkalinity inputs that dominate neutralization of acidity during LATE have not been quantified. Here, we combine investigations of porewater and solid-phase geochemistry from a remediating CASS wetland to derive first-order estimates of alkalinity generating processes and inputs after 6years of LATE. Quantified inputs include: marine derived HCO 3- from tidal exchange; hydrated lime additions; and in situ alkalinity from anaerobic metabolism of organic carbon coupled with reduction of iron and sulfate. A progressive increase in tidal inundation led to the development of significant relationships (a=0.01) between topography and both non-sulfidic, solid-phase Fe(II) and solid-phase reduced inorganic sulfur species. These topographic relationships were conjoined with a digital elevation model, enabling up-scaling of alkalinity estimates to a sub-catchment level. Estimates indicate the relative order of importance of alkalinity generating processes and inputs is Fe reduction (50-64%)>tidal exchange (25-42%)>sulfate reduction (7-13%)>>hydrated lime addition (<1%). Accurately attributing the relative contributions due to Fe and SO 42- reduction was limited by an inability to distinguish between non-sulfidic, solid-phase Fe(II) generated by microbial dissimilatory reduction of Fe(III) or chemical reduction of Fe(III) by H 2S. Nevertheless, the combined alkalinity contribution of these two electron accepting processes accounts for between 58 and 74% of the total. The majority (>99%) of net alkalinity generation was due to either tides or microbial metabolism. This indicates that the LATE remediation technique is both a cost effective means of decreasing soil acidity and is readily transferable to similar CASS landscapes - provided there is adequate supply of suitable electron donors and sufficient regenerative capacity in the adjacent estuarine/marine tidal HCO 3- pool. © 2012 Elsevier B.V.

DOI 10.1016/j.chemgeo.2012.02.008
Citations Scopus - 17
2012 Cheetham MD, Wong VNL, Bush RT, Sullivan LA, Ward NJ, Zawadzki A, 'Mobilisation, alteration, and redistribution of monosulfidic sediments in inland river systems', Journal of Environmental Management, 112 330-339 (2012) [C1]

The accumulation of monosulfidic sediments in inland waterways is emerging as a major environmental issue. Mobilisation and suspension of monosulfidic sediments can result in deox... [more]

The accumulation of monosulfidic sediments in inland waterways is emerging as a major environmental issue. Mobilisation and suspension of monosulfidic sediments can result in deoxygenation, acidification of the water column and mobilisation of trace metals. The controls on monosulfidic sediment mobilisation and the critical thresholds for its scour and entrainment have not been established. This study examines the effect of a minor flood event (average return interval of 5 years) on sulfidic sediment scour in the Wakool River in southern NSW, Australia. Five profiles were sampled within a small (~300 m) reach before and after a minor flood event to determine the degree of sediment scour and transport. The results indicate substantial scour of both monosulfidic sediments and underlying bed sediments (approximately 2100 m3). Changes in the sediment geochemistry suggest large concentrations of monosulfidic sediments had been suspended in the water column, partially-oxidised and redeposited. This is supported by210Pb results from one of the profiles. These results suggest that these monosulfidic sediments can move as bed load during minor flood events. © 2012 Elsevier Ltd.

DOI 10.1016/j.jenvman.2012.08.015
Citations Scopus - 1
2012 Chalmers AC, Erskine WD, Keene AF, Bush RT, 'Relationship between vegetation, hydrology and fluvial landforms on an unregulated sand-bed stream in the Hunter Valley, Australia', Austral Ecology, 37 193-203 (2012) [C1]
Citations Scopus - 4Web of Science - 5
Co-authors Anita Chalmers
2011 Johnston SG, Keene AF, Bush RT, Burton ED, Sullivan LA, Isaacson L, et al., 'Iron geochemical zonation in a tidally inundated acid sulfate soil wetland', Chemical Geology, 280 257-270 (2011)

Tidal inundation is a new technique for remediating coastal acid sulfate soils (CASS). Here, we examine the effects of this technique on the geochemical zonation and cycling of Fe... [more]

Tidal inundation is a new technique for remediating coastal acid sulfate soils (CASS). Here, we examine the effects of this technique on the geochemical zonation and cycling of Fe across a tidally inundated CASS toposequence, by investigating toposequence hydrology, in situ porewater geochemistry, solid-phase Fe fractions and Fe mineralogy. Interactions between topography and tides exerted a fundamental hydrological control on the geochemical zonation, redistribution and subsequent mineralogical transformations of Fe within the landscape. Reductive dissolution of Fe(III) minerals, including jarosite (KFe3(SO4)2(OH)6), resulted in elevated concentrations of porewater Fe2+(>30mmol L-1) in former sulfuric horizons in the upper-intertidal zone. Tidal forcing generated oscillating hydraulic gradients, driving upward advection of this Fe2+-enriched porewater along the intertidal slope. Subsequent oxidation of Fe2+led to substantial accumulation of reactive Fe(III) fractions (up to 8000µmol g-1) in redox-interfacial, tidal zone sediments. These Fe(III)-precipitates were poorly crystalline and displayed a distinct mineralisation sequence related to tidal zonation. Schwertmannite (Fe8O8(OH)6SO4) was the dominant Fe mineral phase in the upper-intertidal zone at mainly low pH (3-4). This was followed by increasing lepidocrocite (¿-FeOOH) and goethite (a-FeOOH) at circumneutral pH within lower-intertidal and subtidal zones. Relationships were evident between Fe fractions and topography. There was increasing precipitation of Fe-sulfide minerals and non-sulfidic solid-phase Fe(II) in the lower intertidal and subtidal zones. Precipitation of Fe-sulfide minerals was spatially co-incident with decreases in porewater Fe2+. A conceptual model is presented to explain the observed landscape-scale patterns of Fe mineralisation and hydro-geochemical zonation. This study provides valuable insights into the hydro-geochemical processes caused by saline tidal inundation of low lying CASS landscapes, regardless of whether inundation is an intentional strategy or due to sea-level rise. © 2010 Elsevier B.V.

DOI 10.1016/j.chemgeo.2010.11.014
Citations Scopus - 54
2011 Claff SR, Burton ED, Sullivan LA, Bush RT, 'Metal partitioning dynamics during the oxidation and acidification of sulfidic soil', Chemical Geology, 286 146-157 (2011)

The oxidation and acidification of sulfidic soil can lead to changes to metal mobility that can have far-reaching environmental consequences. In this study, we examined changes in... [more]

The oxidation and acidification of sulfidic soil can lead to changes to metal mobility that can have far-reaching environmental consequences. In this study, we examined changes in the partitioning and mobility of Fe, Cr, Cu, Mn, Ni and Zn in four sulfidic soils, due to sulphide oxidation driven acidification, over a 90. day period. These changes were examined using a novel six-step sequential extraction procedure specifically developed for acid sulphate soil materials. The results demonstrate two distinct steps for the mobilisation of metals in disturbed acid sulphate soil materials, associated with (i) oxidation and (ii) acidification. Initially, oxidation causes metals to be redistributed from the "pyritic" and "organic" fractions to the "acid-soluble" fraction. Subsequent acidification, due to exceedance of the acid neutralising capacity of the soil, drives the release of metals to the "labile" fraction. This study demonstrates the importance of these metal pools in understanding the short-term processes which mobilise metals in sulfidic soils. © 2011 Elsevier B.V.

DOI 10.1016/j.chemgeo.2011.04.020
Citations Scopus - 20
2011 Johnston SG, Keene AF, Burton ED, Bush RT, Sullivan LA, 'Iron and arsenic cycling in intertidal surface sediments during wetland remediation', Environmental Science and Technology, 45 2179-2185 (2011) [C1]

The accumulation and behavior of arsenic at the redox interface of Fe-rich sediments is strongly influenced by Fe(III) precipitate mineralogy, As speciation, and pH. In this study... [more]

The accumulation and behavior of arsenic at the redox interface of Fe-rich sediments is strongly influenced by Fe(III) precipitate mineralogy, As speciation, and pH. In this study, we examined the behavior of Fe and As during aeration of natural groundwater from the intertidal fringe of a wetland being remediated by tidal inundation. The groundwater was initially rich in Fe 2+ (32 mmol L -1) and As (1.81 µmol L -1) with a circum-neutral pH (6.05). We explore changes in the solid/solution partitioning, speciation and mineralogy of Fe and As during long-term continuous groundwater aeration using a combination of chemical extractions, SEM, XRD, and synchrotron XAS. Initial rapid Fe 2+ oxidation led to the formation of As(III)-bearing ferrihydrite and sorption of >95% of the As(aq) within the first 4 h of aeration. Ferrihydrite transformed to schwertmannite within 23 days, although sorbed/coprecipitated As(III) remained unoxidized during this period. Schwertmannite subsequently transformed to jarosite at low pH (2-3), accompanied by oxidation of remaining Fe 2+. This coincided with a repartitioning of some sorbed As back into the aqueous phase as well as oxidation of sorbed/coprecipitated As(III) to As(V). Fe(III) precipitates formed via groundwater aeration were highly prone to reductive dissolution, thereby posing a high risk of mobilizing sorbed/coprecipitated As during any future upward migration of redox boundaries. Longer-term investigations are warranted to examine the potential pathways and magnitude of arsenic mobilization into surface waters in tidally reflooded wetlands. © 2011 American Chemical Society.

DOI 10.1021/es103403n
Citations Scopus - 39
2011 Burton ED, Johnston SG, Bush RT, 'Microbial sulfidogenesis in ferrihydrite-rich environments: Effects on iron mineralogy and arsenic mobility', Geochimica et Cosmochimica Acta, 75 3072-3087 (2011)

Microbial sulfidogenesis plays a potentially important role in Fe and As biogeochemistry within wetland soils, sediments and aquifers. This study investigates the specific effects... [more]

Microbial sulfidogenesis plays a potentially important role in Fe and As biogeochemistry within wetland soils, sediments and aquifers. This study investigates the specific effects of microbial sulfidogenesis on Fe mineralogy and associated As mobility in mildly acidic (pH 6) and mildly basic (pH 8) advective-flow environments. A series of experiments were conducted using advective-flow columns, with an initial solid-phase comprising As(III)-bearing ferrihydrite-coated quartz sand. Columns for each pH treatment were inoculated with the sulfate-reducing bacteria Desulfovibrio vulgaris, and were compared to additional abiotic control columns. Over a period of 28days, microbial sulfidogenesis (as coupled to the incomplete oxidation of lactate) caused major changes in Fe mineralogy, including replacement of ferrihydrite by mackinawite and magnetite at the in-flow end of the inoculated columns. At pH 8, the Fe2+produced by electron transfer between sulfide and ferrihydrite was mainly retained near its zone of formation. In contrast, at pH 6, much of the produced Fe2+was transported with advecting groundwater, facilitating the downstream Fe2+-catalyzed transformation of ferrihydrite to goethite. At both pH 6 and pH 8, the sulfide-driven reductive dissolution of ferrihydrite and its replacement by mackinawite at the in-flow end of the inoculated columns resulted in substantial mobilization of As into the pore-water. At pH 8, this caused the downstream As concentrations within the inoculated columns to be greater than the corresponding abiotic column. However, the opposite occurred under pH 6 conditions, with the Fe2+-catalyzed transformation of ferrihydrite to goethite in the inoculated columns causing a decrease in downstream As concentrations compared to the abiotic column. Although thermodynamically favorable at intermediate times and depth intervals within the inoculated columns, solid As sulfide phases were undetectable by As XANES spectroscopy. Our findings show that microbial sulfidogenesis can trigger significant As mobilization in subsurface environments with advective groundwater flow. The results also demonstrate that formation of mackinawite by sulfidization of ferric (hydr)oxides is not effective for the immobilization of As, whereas the Fe2+-catalyzed transformation of ferrihydrite to goethite under mildly acidic conditions may mitigate As mobility. © 2011 Elsevier Ltd.

DOI 10.1016/j.gca.2011.03.001
Citations Scopus - 64
2011 Burton ED, Bush RT, Johnston SG, Sullivan LA, Keene AF, 'Sulfur biogeochemical cycling and novel Fe-S mineralization pathways in a tidally re-flooded wetland', Geochimica et Cosmochimica Acta, 75 3434-3451 (2011)

Sulfur biogeochemical cycling and associated Fe-S mineralization processes exert a major influence over acidity dynamics, electron flow and contaminant mobility in wetlands, benth... [more]

Sulfur biogeochemical cycling and associated Fe-S mineralization processes exert a major influence over acidity dynamics, electron flow and contaminant mobility in wetlands, benthic sediments and groundwater systems. While S biogeochemical cycling has been studied intensively in many environmental settings, relatively little direct information exists on S cycling in formerly drained wetlands that have been remediated via tidal re-flooding. This study focuses on a tidal wetland that was drained in the 1970s (causing severe soil and water acidification), and subsequently remediated by controlled re-flooding in 2002. We examine SO42- reduction rates and Fe-S mineralization at the tidal fringe, 7years after the commencement of re-flooding. The initial drainage of the wetland examined here caused in-situ pyrite (FeS2) oxidation, resulting in the drained soil layers being highly acidic and rich in SO42--bearing Fe(III) minerals, including jarosite (KFe3(SO4)2(OH)6). Tidal re-flooding has neutralized much of the previous acidity, with the pore-water pH now mostly spanning pH 5-7. The fastest rates of in-situ SO42- reduction (up to ~300nmolcm-3day-1) occur within the inter-tidal zone in the near-surface soil layers (to ~60cm below ground surface). The SO42- reduction rates correlate with pore-water dissolved organic C concentrations, thereby suggesting that electron donor supply was the predominant rate determining factor. Elemental S was a major short-term product of SO42- reduction, comprising up to 69% of reduced inorganic S in the near-surface soil layers. This enrichment in elemental S can be partly attributed to interactions between biogenic H2S and jarosite - a process that also contributed to enrichment in pore-water Fe2+(up to 55mM) and SO42- (up to 50mM). The iron sulfide thiospinel, greigite (Fe3S4), was abundant in near-surface soil layers within the inter- to sub-tidal zone where tidal water level fluctuations created oscillatory redox conditions. There was evidence for relatively rapid pyrite re-formation within the re-flooded soil layers. However, the results indicate that pyrite re-formation has occurred mainly in the lower formerly drained soil layers, whereas the accumulation of elemental S and greigite has been confined towards the soil surface. The discovery that pyrite formation was spatially decoupled from that of elemental S and greigite challenges the concept that greigite is an essential precursor required for sedimentary pyrite formation. In fact, the results suggest that greigite and pyrite may represent distinct end-points of divergent Fe-S mineralization pathways. Overall, this study highlights novel aspects of Fe-S mineralization within tidal wetlands that have been drained and re-flooded, in contrast to normal, undisturbed tidal wetlands. As such, the long-term biogeochemical trajectory of drained and acidified wetlands that are remediated by tidal re-flooding cannot be predicted from the well-studied behaviour of normal tidal wetlands. © 2011 Elsevier Ltd.

DOI 10.1016/j.gca.2011.03.020
Citations Scopus - 75
2011 Johnston SG, Keene AF, Bush RT, Sullivan LA, Wong VNL, 'Tidally driven water column hydro-geochemistry in a remediating acidic wetland', Journal of Hydrology, 409 128-139 (2011) [C1]

Managed tidal inundation is a newly evolved technique for remediating coastal acid sulphate soil (CASS) wetlands. However, there remains considerable uncertainty regarding the hyd... [more]

Managed tidal inundation is a newly evolved technique for remediating coastal acid sulphate soil (CASS) wetlands. However, there remains considerable uncertainty regarding the hydro-geochemical pathways and spatiotemporal dynamics of residual H+and metal(loid) mobilisation into the tidal fringe surface waters of these uniquely iron-rich landscapes. Here, we examine the hydrology and water column chemistry across the intertidal slope of a remediating CASS wetland during several tide cycles. There was extreme spatial and temporal dynamism in water column chemistry, with pH fluctuating by ~3 units (~3.5-6.5) during a single tide cycle. Acute acidity was spatially confined to the upper intertidal slope, reflecting surface sediment properties, and tidal overtopping is an important pathway for mobilisation of residual H+and Al3+to the water column. Marine derived HCO3- was depleted from surface waters migrating across the intertidal slope and a strong gradient in HCO3- was observed from the tidal fringe to the adjacent tributary channel and nearby estuary. Tidal forcing generated oscillating hydraulic gradients in the shallow fringing aquifer, favouring ebb-tide seepage and driving rapid, heterogeneous advection of groundwater on the lower intertidal slope via surface connected macropores. A combination of diffusive and advective flux across the sediment-water interface led to persistent, elevated surface water Fe2+(~10-1000µM). The geochemical processes associated with Fe2+mobilisation displayed distinct spatial zonation, with low pH, proton-promoted desorption occurring on the upper intertidal slope, whilst circum-neutral pH, Fe(III)-reducing processes dominated the lower intertidal slope. Arsenic was also mobilised into surface waters on the lower intertidal slope under moderate pH (~6.0) conditions and was strongly positively correlated with Fe2+. Saturation index values for aragonite were substantially depressed (-1 to -5) and significantly negatively correlated with elevation, thereby presenting a barrier to re-colonisation of the upper intertidal slope by calcifying benthic organisms. These findings highlight the spatially complex hydrological and geochemical controls on surface water quality that can occur in tidally inundated acid sulphate soil environments. © 2011 Elsevier B.V.

DOI 10.1016/j.jhydrol.2011.08.010
Citations Scopus - 13
2011 Claff SR, Sullivan LA, Burton ED, Bush RT, Johnston SG, 'Partitioning of metals in a degraded acid sulfate soil landscape: Influence of tidal re-inundation', Chemosphere, 85 1220-1226 (2011) [C1]

The oxidation and acidification of sulfidic soil materials results in the re-partitioning of metals, generally to more mobile forms. In this study, we examine the partitioning of ... [more]

The oxidation and acidification of sulfidic soil materials results in the re-partitioning of metals, generally to more mobile forms. In this study, we examine the partitioning of Fe, Cr, Cu, Mn, Ni and Zn in the acidified surface soil (0-0.1. m) and the unoxidised sub-soil materials (1.3-1.5. m) of an acid sulfate soil landscape. Metal partitioning at this acidic site was then compared to an adjacent site that was previously acidified, but has since been remediated by tidal re-inundation. Differences in metal partitioning were determined using an optimised six-step sequential extraction procedure which targets the " labile" , " acid-soluble" , " organic" , " crystalline oxide" , " pyritic" and " residual" fractions. The surficial soil materials of the acidic site had experienced considerable losses of Cr, Cu, Mn and Ni compared to the underlying parent material due to oxidation and acidification, yet only minor losses of Fe and Zn. In general, the metals most depleted from the acidified surface soil materials exhibited the greatest sequestration in the surface soil materials of the tidally remediated site. An exception to this was iron, which accumulated to highly elevated concentrations in the surficial soil materials of the tidally remediated site. The " acid-soluble" , " organic" and " pyritic" fractions displayed the greatest increase in metals following tidal remediation. This study demonstrates that prolonged tidal re-inundation of severely acidified acid sulfate soil landscapes leads to the immobilisation of trace metals through the surficial accumulation of iron oxides, organic material and pyrite. © 2011 Elsevier Ltd.

DOI 10.1016/j.chemosphere.2011.07.013
Citations Scopus - 12
2011 Wong VNL, Johnston SG, Burton ED, Bush RT, Sullivan LA, Slavich PG, 'Anthropogenic forcing of estuarine hypoxic events in sub-tropical catchments: Landscape drivers and biogeochemical processes', Science of the Total Environment, 409 5368-5375 (2011) [C1]

Episodic hypoxic events can occur following summer floods in sub-tropical estuaries of eastern Australia. These events can cause deoxygenation of waterways and extensive fish mort... [more]

Episodic hypoxic events can occur following summer floods in sub-tropical estuaries of eastern Australia. These events can cause deoxygenation of waterways and extensive fish mortality. Here, we present a conceptual model that links key landscape drivers and biogeochemical processes which contribute to post-flood hypoxic events. The model provides a framework for examining the nature of anthropogenic forcing. Modification of estuarine floodplain surface hydrology through the construction of extensive drainage networks emerges as a major contributing factor to increasing the frequency, magnitude and duration of hypoxic events. Forcing occurs in two main ways. Firstly, artificial drainage of backswamp wetlands initiates drier conditions which cause a shift in vegetation assemblages from wetland-dominant species to dryland-dominant species. These species, which currently dominate the floodplain, are largely intolerant of inundation and provide abundant labile substrate for decomposition following flood events. Decomposition of this labile carbon pool consumes oxygen in the overlying floodwaters, and results in anoxic conditions and waters with excess deoxygenation potential (DOP). Carbon metabolism can be strongly coupled with microbially-mediated reduction of accumulated Fe and Mn oxides, phases which are common on these coastal floodplain landscapes. Secondly, artificial drainage enhances discharge rates during the flood recession phase. Drains transport deoxygenated high DOP floodwaters rapidly from backswamp wetlands to the main river channel to further consume oxygen. This process effectively displaces the natural carbon metabolism processes from floodplain wetlands to the main channel. Management options to reduce the impacts of post-flood hypoxia include i) remodifying drainage on the floodplain to promote wetter conditions, thereby shifting vegetation assemblages towards inundation-tolerant species, and ii) strategic retention of floodwaters in the backswamp wetlands to reduce the volume and rate during the critical post-flood recession phase. © 2011 Elsevier B.V.

DOI 10.1016/j.scitotenv.2011.08.065
Citations Scopus - 9
2011 Keene AF, Johnston SG, Bush RT, Sullivan LA, Burton ED, McElnea AE, et al., 'Effects of hyper-enriched reactive Fe on sulfidisation in a tidally inundated acid sulfate soil wetland', Biogeochemistry, 103 263-279 (2011)

Solid phase Fe and S fractions were examined in an acid sulfate soil (ASS) wetland undergoing remediation via tidal inundation. Considerable diagenetic enrichment of reactive Fe(I... [more]

Solid phase Fe and S fractions were examined in an acid sulfate soil (ASS) wetland undergoing remediation via tidal inundation. Considerable diagenetic enrichment of reactive Fe(III) oxides (HCl- and dithionite-extractable) occurred near the soil surface (0-0.05 m depth), where extremely large concentrations up to 3534 µmol/g accounted for ~90% of the total Fe pool. This major source of reactive Fe exerts a substantial influence on S cycling and the formation, speciation and transformation of reduced inorganic S (RIS) in tidally inundated ASS. Under these geochemical conditions, acid volatile sulfide (AVS; up to 57 µmol/g) and elemental sulfur (S0; up to 41 µmol/g) were the dominant fractions of RIS in near surface soils. AVS-S to pyrite-S ratios exceeded 2.9 near the surface, indicating that abundant reactive Fe favoured the accumulation of AVS minerals and S0 over pyrite. This is supported by the significant correlation of poorly crystalline Fe with AVS-S and S0-S contents (r = 0.83 and r = 0.85, respectively, P < 0.01). XANES spectroscopy provided direct evidence for the presence of a greigite-like phase in AVS-S measured by chemical extraction. While the abundant reactive Fe may limit the transformation of AVS minerals and S0 to pyrite during early diagenesis (~5 years), continued sulfidisation over longer time scales is likely to eventually lead to enhanced sequestration of S within pyrite (with a predicted 8% pyrite by mass). These findings provide an important understanding of sulfidisation processes occurring in reactive Fe-enriched, tidally inundated ASS landscapes. © 2010 Springer Science+Business Media B.V.

DOI 10.1007/s10533-010-9461-2
Citations Scopus - 27
2010 Burton ED, Johnston SG, Watling K, Bush RT, Keene AF, Sullivan LA, 'Arsenic effects and behavior in association with the fe(II)-catalyzed transformation of schwertmannite', Environmental Science and Technology, 44 2016-2021 (2010)

In acid-mine drainage and acid-sulfate soil environments, the cycling of Fe and As are often linked to the formation and fate of schwertmannite(Fe 8O8(OH)8-2x(SO4)x).When schwertm... [more]

In acid-mine drainage and acid-sulfate soil environments, the cycling of Fe and As are often linked to the formation and fate of schwertmannite(Fe 8O8(OH)8-2x(SO4)x).When schwertmanniterich material is subjected to near-neutral Fe(III)-reducing conditions (e.g., in reflooded acid-sulfate soils or mining-lake sediments), the resulting Fe(II) can catalyze transformation of schwertmannite to goethite. This work examines the effects of arsenic(V) and arsenic(III) on the Fe(II)-catalyzed transformation of schwertmannite and investigates the associated consequences of this mineral transformation for arsenic mobilization. A series of 9-day anoxic transformation experiments were conducted with synthetic schwertmannite and various additions of Fe(II), As(III), and As(V). X-ray diffraction (XRD) and Fe K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy demonstrated that, in the absence of Fe(II), schwertmannite persisted as the dominant mineral phase. Under arsenic-free conditions, 10 mM Fe(II) catalyzed rapid and complete transformation of schwertmannite to goethite. However, the magnitude of Fe(II)-catalyzed transformation decreased to 72% in the presence of 1 mM As(III) and to only 6% in the presence of 1mM As(V). This partial Fe(II)-catalyzed transformation of As(III)-sorbed schwertmannite did not cause considerable As(III) desorption. In contrast, the formation of goethite via partial transformation of As(III)- and As(V)-sorbed schwertmannite significantly decreased arsenic mobilization under Fe(III)-reducing conditions. This implies that the Fe(II)-catalyzed transformation of schwertmannite to goethite may help to stabilize solid-phase arsenic and retard its subsequent release to groundwater. © 2010 American Chemical Society.

DOI 10.1021/es903424h
Citations Scopus - 41
2010 Johnston SG, Keene AF, Burton ED, Bush RT, Sullivan LA, Mcelnea AE, et al., 'Arsenic mobilization in a seawater inundated acid sulfate soil', Environmental Science and Technology, 44 1968-1973 (2010)

Tidal seawater inundation of coastal acid sulfate soils can generate Fe- and SO4-reducing conditions in previously oxicacidic sediments, This creates potential for mobilization of... [more]

Tidal seawater inundation of coastal acid sulfate soils can generate Fe- and SO4-reducing conditions in previously oxicacidic sediments, This creates potential for mobilization of As during the redox transition. We explore the consequences for As by investigating the hydrology, porewater geochemistry, solid-phase speciation, and mineralogical partitioning of As across two tidal fringe toposequences. Seawater inundation induced a tidally controlled redox gradient. Maximum porewater As (~400µg/L) occurred in the shallow (<1 m), intertidal, redox transition zone between Fe-oxidizing and SO4-reducing conditions. Primary mechanisms of As mobilization include the reduction of solid-phase As(V) to As(III), reductive dissolution of As(V)-bearing secondary Fe(III) minerals and competitive anion desorption. Porewater As concentrations decreased in the zone of contemporary pyrite reformation, Oscillating hydraulic gradients caused by tidal pumping promote upward advection of As and Fe2+-enriched porewater in the intertidal zone, leading to accumulation of As(V)-enriched Fe(III) (hydr)oxides at the oxic sediment-water interface. While this provides a natural reactive-Fe barrier, it does not completely retard the flux of porewater As to overtopping surface waters. Furthermore, the accumulated Fe minerals may be prone to future reductive dissolution, A conceptual model describing As hydro-geochemical coupling across an intertidal fringe is presented. © 2010 American Chemical Society.

DOI 10.1021/es903114z
Citations Scopus - 33
2010 Claff SR, Sullivan LA, Burton ED, Bush RT, 'A sequential extraction procedure for acid sulfate soils: Partitioning of iron', Geoderma, 155 224-230 (2010)

A new sequential extraction scheme for acid sulfate soil materials has been evaluated for iron partitioning in a range of synthetic iron-bearing minerals and natural acid sulfate ... [more]

A new sequential extraction scheme for acid sulfate soil materials has been evaluated for iron partitioning in a range of synthetic iron-bearing minerals and natural acid sulfate soil materials. This sequential extraction procedure employs six steps to quantify (1) exchangeable (magnesium chloride extractable), (2) acid (hydrochloric acid) soluble, (3) reactive organic-bound (pyrophosphate extractable), (4) crystalline oxide (citrate buffered dithionite (CBD)) extractable, (5) pyrite-bound (nitric acid extractable) and (6) residual (acid/peroxide digestible) forms of iron. Given its intended use for acid sulfate soil materials that frequently contain pyrite, a primary aim of this new sequential extraction procedure was to differentiate iron bound in pyrite from iron contained in other minerals. The results demonstrated that dissolution of pyrite was effectively isolated in the pyrite-bound extraction step, with dissolution of other iron mineral phases (i.e. akaganeite, ferrihydrite, goethite, hematite, jarosite, magnetite, and schwertmannite) occurring within the other five extraction steps. Following a systematic examination of these synthetic iron mineral phases, the sequential extraction scheme was applied to an acid sulfate soil profile, with detailed data presented for two soil layers: one representative of the sulfidic (unoxidised) conditions, and the other sulfuric (oxidised) conditions. Partitioning data for pyrite-bound iron in the acid sulfate soil profile showed good agreement with that calculated via the independently measured pyrite-bound reduced sulfur. This study indicates that the new sequential extraction procedure is suitable for the assessment of iron partitioning in acid sulfate soil materials. © 2009 Elsevier B.V. All rights reserved.

DOI 10.1016/j.geoderma.2009.12.002
Citations Scopus - 68
2010 Claff SR, Burton ED, Sullivan LA, Bush RT, 'Effect of sample pretreatment on the fractionation of Fe, Cr, Ni, Cu, Mn, and Zn in acid sulfate soil materials', Geoderma, 159 156-164 (2010)

A sequential extraction procedure was applied to acid sulfate soil materials from a soil profile to investigate the effect of sample pretreatment on the geochemical fractionation ... [more]

A sequential extraction procedure was applied to acid sulfate soil materials from a soil profile to investigate the effect of sample pretreatment on the geochemical fractionation of selected metals. The samples were prepared for analysis by oven-drying, sieving and grinding the soil, or were examined as collected in field condition. The soil profile encompassed oxidising conditions near the surface, through to reducing conditions at depth. Six metals (Fe, Cr, Ni, Mn, Cu, and Zn) were measured during the sequential extraction procedure, and their fractionation determined in the oxidised and in the reduced zone. Although cumulative totals (the sum of all steps in the sequential extraction procedure) for the metals extracted from both the field condition and dried/ground samples were similar, some significant differences in fractionation within individual extraction steps were observed. Of particular interest was the redistribution of metals from the sulfide-bearing (pyrite-bound) fraction to the more readily available fractions (i.e. labile and acid-soluble), as a result of oven-drying and grinding. The results indicate that when assessing metal fractionation in acid sulfate soil materials, samples should be analysed in field condition in order to avoid the considerable metal fractionation artifacts that are induced by drying and grinding. © 2010 Elsevier B.V.

DOI 10.1016/j.geoderma.2010.07.007
Citations Scopus - 13
2010 Wong VNL, Johnston SG, Burton ED, Bush RT, Sullivan LA, Slavich PG, 'Seawater causes rapid trace metal mobilisation in coastal lowland acid sulfate soils: Implications of sea level rise for water quality', Geoderma, 160 252-263 (2010)

Coastal floodplains are highly vulnerable to inundation with saline water and the likelihood of inundation will increase with sea level rise. Sediment samples from floodplains con... [more]

Coastal floodplains are highly vulnerable to inundation with saline water and the likelihood of inundation will increase with sea level rise. Sediment samples from floodplains containing coastal lowland acid sulfate soils (CLASS) in eastern Australia were subjected to increasing seawater concentration to examine the probable effects of sea level rise on acidity and metal desorption. Ten soils were mixed with synthetic seawater concentrations varying from 0% to 100% at a solid:solution ratio of 1:10 for 4h. There was a slight decrease in pH (¿0.5 units) with increasing seawater concentration following treatment, yet, calculated acidity increased significantly. In most soil treatments, Al was the dominant component of the calculated acidity pool. Al dominated the exchange complex in the CLASS and, correspondingly, was the major metal ion desorbed. In general, concentrations of soluble and exchangeable Al, Fe2+, Ni, Mn and Zn in all soil extracts increased with increasing salinity. Increasing trace metal concentrations with increasing seawater concentration is attributed to the combined effects of exchange processes and acidity. The increasing ionic strength of the seawater treatments displaces trace metals and protons adsorbed on sediments, causing an initial decrease in pH. Hydrolysis of desorbed acidic metal cations can further contribute to acidity and increase mobilisation of trace metals. These findings imply that saline inundation of CLASS environments, even by relatively brackish water may cause rapid, shorter-term water quality changes and a pulse release of acidity due to desorption of acidic metal cations. © 2010 Elsevier B.V.

DOI 10.1016/j.geoderma.2010.10.002
Citations Scopus - 14
2010 Keene AF, Johnston SG, Bush RT, Burton ED, Sullivan LA, 'Reactive trace element enrichment in a highly modified, tidally inundated acid sulfate soil wetland: East Trinity, Australia', Marine Pollution Bulletin, 60 620-626 (2010)

This study examines the abundance of trace elements in surface sediments of a former acid sulfate soil (ASS) wetland subjected to marine tidal inundation. Sediment properties of t... [more]

This study examines the abundance of trace elements in surface sediments of a former acid sulfate soil (ASS) wetland subjected to marine tidal inundation. Sediment properties of this highly modified study site are compared with those of an adjacent unmodified, intertidal mangrove forest. Whilst some trace elements (Al, Cd, Mn, Ni and Zn) were clearly depleted due to mobilisation and leaching in the previous oxic-acidic phase, other trace elements (As and Cr) displayed significant enrichment in the tidally inundated ASS. Many trace elements were strongly associated with the reactive Fe and acid volatile sulfide (AVS) fractions, suggesting that trace elements may be adsorbed to abundant reactive Fe phases or sequestered as sulfide minerals. These findings provide an important understanding of the fate and mobility of reactive iron, AVS and trace elements during tidal remediation of a formerly acidified Great Barrier Reef (GBR) catchment. © 2010 Elsevier Ltd.

DOI 10.1016/j.marpolbul.2010.02.006
Citations Scopus - 22
2010 Ward NJ, Bush RT, Burton ED, Appleyard S, Wong S, Sullivan LA, Cheeseman PJ, 'Monosulfidic black ooze accumulations in sediments of the Geographe Bay area, Western Australia', Marine Pollution Bulletin, 60 2130-2136 (2010)

Mobilisation of sedimentary monosulfidic black ooze (MBO) may result in rapid deoxygenation and acidification of surface waters, and release of potentially toxic metals. This stud... [more]

Mobilisation of sedimentary monosulfidic black ooze (MBO) may result in rapid deoxygenation and acidification of surface waters, and release of potentially toxic metals. This study examines the extent and nature of MBO accumulation in the Geographe Bay area, Western Australia. MBO accumulations were found to be widespread in benthic sediments of the Geographe Bay area with acid-volatile sulfide (AVS) contents as high as 320µmolg-1. The MBO materials often had unusually high dissolved sulfide (S-II) concentrations in their pore-waters (up to 610mgL-1) and elevated elemental sulfur (S0) contents (up to 51µmolg-1). Dissolved S-IIis able to accumulate due to limited iron availability and S0is largely its partial oxidation product. The availability of organic carbon and Fe limited MBO accumulation at many sites. A comparison of AVS and simultaneously extracted metal (SEM) concentrations has shown that metals are likely to be bound in sulfide complexes. © 2010 Elsevier Ltd.

DOI 10.1016/j.marpolbul.2010.07.029
Citations Scopus - 7
2010 Wong VNL, Johnston SG, Bush RT, Sullivan LA, Clay C, Burton ED, Slavich PG, 'Spatial and temporal changes in estuarine water quality during a post-flood hypoxic event', Estuarine, Coastal and Shelf Science, 87 73-82 (2010)

A major fish kill occurred in the Richmond River estuary in January 2008 due to oxygen depletion following extensive overbank flooding. This paper examines spatial and temporal ch... [more]

A major fish kill occurred in the Richmond River estuary in January 2008 due to oxygen depletion following extensive overbank flooding. This paper examines spatial and temporal changes in the chemistry of main channel waters, thereby identifying the primary sources of deoxygenating water. Over 40¿km of the mid- to lower estuary main channel was deoxygenated within seven days of the flood peak. Hypoxia was confined to downstream of the confluences with mid-estuary backswamp basins and occurred during the later phase of the flood recession. Water chemistry at key locations in the estuary indicated elevated concentrations of redox sensitive species associated with acid sulfate soils (ASS) during the hypoxic period. Peak concentrations of Fe2+up to 18.2¿µmol¿L-1, dissolved Mn up to 4.3¿µmol¿L-1, chemical oxygen demand (COD) up to 2052¿µmol¿L-1, dissolved organic carbon (DOC) up to 960¿µmol¿L-1and elemental S0up to 4.7¿µmol¿L-1were found in the backswamp discharge confluences and mid-estuary main channel locations. The geochemical signature of main channel floodwaters identifies anaerobic decomposition of floodplain vegetation in ASS backswamps as a primary process leading to generation of hypoxic waters. The transport of these hypoxic floodwaters to the estuary has been accelerated and prolonged by extensive floodplain drainage, thereby enhancing the magnitude and duration of estuarine deoxygenation. © 2009 Elsevier Ltd.

DOI 10.1016/j.ecss.2009.12.015
Citations Scopus - 23
2010 Johnston SG, Burton ED, Bush RT, Keene AF, Sullivan LA, Smith D, et al., 'Abundance and fractionation of Al, Fe and trace metals following tidal inundation of a tropical acid sulfate soil', Applied Geochemistry, 25 323-335 (2010)

Tidal inundation was restored to a severely degraded tropical acid sulfate soil landscape and subsequent changes in the abundance and fractionation of Al, Fe and selected trace me... [more]

Tidal inundation was restored to a severely degraded tropical acid sulfate soil landscape and subsequent changes in the abundance and fractionation of Al, Fe and selected trace metals were investigated. After 5 a of regular tidal inundation there were large decreases in water-soluble and exchangeable Al fractions within former sulfuric horizons. This was strongly associated with decreased soil acidity and increases in pH, suggesting pH-dependent immobilisation of Al via precipitation as poorly soluble phases. The water-soluble fractions of Fe, Zn, Ni and Mn also decreased. However, there was substantial enrichment (2-5×) of the reactive Fe fraction (FeR; 1 M HCl extractable) near the soil surface, plus a closely corresponding enrichment of 1 M HCl extractable Cr, Zn, Ni and Mn. Surficial accumulations of Fe(III) minerals in the inter-tidal zone were poorly crystalline (up to 38% FeR) and comprised mainly of schwertmannite (Fe8O8(OH)6SO4) with minor quantities of goethite (a-FeOOH) and lepidocrocite (¿-FeOOH). These Fe (III) mineral accumulations provide an effective substrate for the adsorption/co-precipitation and accumulation of trace metals. Arsenic displayed contrary behaviour to trace metals with peak concentrations (~60 µg g-1) near the redox minima. Changes in the abundance and fractionation of the various metals can be primarily explained by the shift in the geochemical regime from oxic-acidic to reducing-circumneutral conditions, combined with the enrichment of reactive Fe near the soil surface. Whilst increasing sequestration of trace metals via sulfidisation is likely to occur over the long-term, the current abundance of reactive Fe near the sediment-water interface favours a dynamic environment with respect to metals in the tidally inundated areas. © 2009 Elsevier Ltd. All rights reserved.

DOI 10.1016/j.apgeochem.2009.11.015
Citations Scopus - 35
2010 Cheetham MD, Bush RT, Keene AF, Erskine WD, 'Nonsynchronous, episodic incision: Evidence of threshold exceedance and complex response as controls of terrace formation', Geomorphology, 123 320-329 (2010) [C1]
DOI 10.1016/j.geomorph.2010.07.024
Citations Scopus - 9Web of Science - 9
2010 Cheetham MD, Keene AF, Erskine WD, Bush RT, Fitzsimmons K, Jacobsen GE, Fallon SJ, 'Resolving the Holocene alluvial record in southeastern Australia using luminescence and radiocarbon techniques', Journal of Quaternary Science, 25 1160-1168 (2010) [C1]
DOI 10.1002/jqs.1396
Citations Scopus - 14Web of Science - 13
2010 Cheetham MD, Bush RT, Keene AF, Erskine WD, Fitzsimmons KE, 'Longitudinal correlation of Late Quaternary terrace sequences of Widden Brook, southeastern Australia', Australian Journal of Earth Sciences, 57 97-109 (2010) [C1]
DOI 10.1080/08120090903416229
Citations Scopus - 7Web of Science - 7
2009 Burton ED, Bush RT, Sullivan LA, Hocking RK, Mitchell DRG, Johnston SG, et al., 'Iron-monosulfide oxidation in natural sediments: Resolving microbially mediated S transformations using XANES, electron microscopy, and selective extractions', Environmental Science and Technology, 43 3128-3134 (2009)

Iron-monosulfide oxidation and associated S transformations in a natural sediment were examined by combining selective extractions, electron microscopy and S K-edge X-ray absorpti... [more]

Iron-monosulfide oxidation and associated S transformations in a natural sediment were examined by combining selective extractions, electron microscopy and S K-edge X-ray absorption near-edge structure (XANES) spectroscopy. The sediment examined in this study was collected from a waterway receiving acid-sulfate soil drainage. It contained a high acid-volatile sulfide content (1031 µ mol g-1), reflecting an abundance of iron-monosulfide. The iron-monosulfide speciation in the initial sediment sample was dominated by nanocrystalline mackinawite (tetragonal FeS). At near-neutral pH and an O 2 partial pressure of ~0.2 atm, the mackinawite was found to oxidize rapidly, with a half-time of 29 ± 2 min. This oxidation rate did not differ significantly (P < 0.05) between abiotic versus biotic conditions, demonstrating that oxidation of nanocrystalline mackinawite was not microbially mediated. The extraction results suggested that elemental S (S08) was a key intermediate S oxidation product. Transmission electron microscopy showed the S08 to be amorphous nanoglobules, 100-200 nm in diameter. The quantitative importance of S08 was confirmed by linear combination XANES spectroscopy, after accounting for the inherent effect of the nanoscale S08 particle-size on the corresponding XANES spectrum. Both the selective extraction and XANES data showed that oxidation of S08 SO42- was madiated by microbial activity. In addition to directly revealing important S transformations, the XANES results support the accuracy of the selective extraction scheme employed here. © 2009 American Chemical Society.

DOI 10.1021/es8036548
Citations Scopus - 71
2009 Burton ED, Bush RT, Johnston SG, Watling KM, Hocking RK, Sullivan LA, Parker GK, 'Sorption of Arsenic(V) and Arsenic(III) to schwertmannite', Environmental Science and Technology, 43 9202-9207 (2009)

This study describes the sorption of As(V) and As(III) to schwertmannite as a function of pH and arsenic loading. In general, sorption of As(V) was greatest at low pH, whereas hig... [more]

This study describes the sorption of As(V) and As(III) to schwertmannite as a function of pH and arsenic loading. In general, sorption of As(V) was greatest at low pH, whereas high pH favored the sorption of As(III). The actual pH of equivalent As(V) and As(III) sorption was strongly loading dependent, decreasing from pH ~ 8.0 at loadings <120 mmolAs mol Fe-1 to pH ~ 4.6 at a loading of 380 mmolAs molFe-1. Sorption isotherms for As(V) were characterized by strong partitioning to the schwertmannite solid-phase at low loadings and sorption capacities of 225-330 mmolAs(V) molFe-1 at high loadings. In contrast, the As(III) isotherms revealed a weak affinity for sorption of As(III) versus As(V) at low loadings yet a greater affinity for As(III) sorption compared with As(V) at high loadings (when pH > 4.6). Sorption of As(V) and As(III) caused significant release of SO 42- from within the schwertmannite solid-phase, without major degradation of the schwertmannite structure (as evident by X-ray diffraction and Raman spectroscopy). This can be interpreted as arsenic sorption via incorporation into the schwertmannite structure, rather than merely surface complexation at the mineral-water interface. The results of this study have important implications for arsenic mobility in the presence of schwertmannite, such as in areas affected by acidmine drainage and acid-sulfate soils. In particular, arsenic speciation, arsenic loading, and pH should be considered when predicting and managing arsenic mobility in schwertmanniterich systems. © 2009 American Chemical Society.

DOI 10.1021/es902461x
Citations Scopus - 116
2009 Sullivan LA, Ward NJ, Bush RT, Burton ED, 'Improved identification of sulfidic soil materials by a modified incubation method', Geoderma, 149 33-38 (2009)

This study examines the acidification behaviour and rate of sulfidic-sulfur oxidation in the incubation method that is currently used in soil taxonomies to identify sulfidic mater... [more]

This study examines the acidification behaviour and rate of sulfidic-sulfur oxidation in the incubation method that is currently used in soil taxonomies to identify sulfidic materials, for some clayey textured soil materials. 'Sulfidic' in these taxonomies identifies that a soil material is capable of becoming extremely acidic (i.e. pH < 4) as a result of oxidation of sulfide minerals contained in that soil material. As well as examining incubation slabs of acid sulfate soil materials with the standard 10¿mm thickness, the utility of thinner (i.e. 2¿mm thick) incubation slabs of these soil materials for identification of sulfidic soil materials was also examined. The clayey soil materials in the 2¿mm thick slabs exhibited more rapid sulfidic-sulfur oxidation and acidification and resulted in fewer false-negative sulfidic soil material identifications than did the use of 10¿mm thick slabs. However, the rates of sulfidic-sulfur oxidation and sulfide-derived acidification within the slabs (whether 2¿mm or 10¿mm thick) were not always rapid enough during incubation for the full expression of acidification to be evident within the maximum incubation duration of 8¿weeks required by soil classification taxonomies. The results indicate the incubation method for determination of the sulfidic nature of soil materials for soil classification purposes could be improved to reduce the risk of false-negative identification by: i. allowing the use of 2¿mm thick slabs, and ii. changing the maximum duration of incubation from 8¿weeks to until a stable pH is reached after at least 8¿weeks of incubation. © 2008.

DOI 10.1016/j.geoderma.2008.11.019
Citations Scopus - 16
2009 Johnston SG, Keene AF, Bush RT, Burton ED, Sullivan LA, Smith D, et al., 'Contemporary pedogenesis of severely degraded tropical acid sulfate soils after introduction of regular tidal inundation', Geoderma, 149 335-346 (2009)

Marine tidal inundation was partially restored to a severely degraded tropical acid sulfate soil landscape after having been excluded for over 30¿years. The effects on soil acidit... [more]

Marine tidal inundation was partially restored to a severely degraded tropical acid sulfate soil landscape after having been excluded for over 30¿years. The effects on soil acidity and iron-sulfide mineral reformation were investigated by comparing the geochemistry of soils before and after five years of regular tidal inundation. The soil pH increased by 2-3 units and titratable actual acidity (TAA) decreased by ~ 40-50¿µmol H+g- 1within former sulfuric horizons. Relict acidity remained at depth (> 1¿m) in the underlying sulfidic horizons. d34S data indicate that tidal inundation caused exchange of marine solutes within former sulfuric horizons, but not within underlying sulfidic material. There was considerable reformation of pyrite within former sulfuric horizons after tidal inundation with reduced inorganic sulfur increasing by ~ 60¿µmol g- 1. Acid-volatile sulfide also accumulated, but mainly near the soil surface (up to 16¿µmol g- 1). Reduction of Fe(III) minerals strongly influences the geochemistry of the tidally inundated soils. After tidal inundation the soil pH and Eh closely followed the iron redox couple and there was non-sulfidic solid-phase Fe(II) up to 600¿µmol g- 1. There was also substantial diagenetic enrichment of poorly crystalline Fe-oxides near the soil surface following tidal inundation, with reactive Fe spanning 400-1800¿µmol g- 1. While the decreases in soil acidity documented here are likely due to a combination of marine alkalinity inputs and reduction of both Fe and SO42-, the relative importance of each process remains to be determined. This study demonstrates that marine tidal inundation can be an effective landscape-scale strategy for ameliorating severe acidity associated with drained acid sulfate soils. © 2008 Elsevier B.V. All rights reserved.

DOI 10.1016/j.geoderma.2008.12.013
Citations Scopus - 39
2009 Johnston SG, Hirst P, Slavich PG, Bush RT, Aaso T, 'Saturated hydraulic conductivity of sulfuric horizons in coastal floodplain acid sulfate soils: Variability and implications', Geoderma, 151 387-394 (2009)

The saturated hydraulic conductivity (Ks) of sulfuric horizons exerts a fundamental control on the connectivity between shallow groundwater and drains in coastal acid sulfate soil... [more]

The saturated hydraulic conductivity (Ks) of sulfuric horizons exerts a fundamental control on the connectivity between shallow groundwater and drains in coastal acid sulfate soils (CASS), strongly influencing rates of lateral seepage towards or from field drains. The Ksof sulfuric horizons was assessed on seven major coastal floodplains of eastern Australia using an in situ recovery technique conducted in ~ 0.4-0.65¿m deep pits. Duplicate recovery tests were conducted in a total of 148 pits located in 32 separate geomorphic units across the seven coastal floodplains. Most pits were constructed in clay soils with acidic (pH < 4.0) shallow groundwater. The Ksspanned four orders of magnitude, ranging from < 0.5¿m day- 1to > 500¿m day- 1. Data are log normally distributed and the median Kswas ~ 15.4¿m day- 1. Over 40% of the pits had values > 20¿m day- 1, challenging the assumption that Ksin sulfuric horizons in CASS landscapes is generally low. Visual observations confirm that high Ksvalues were strongly associated with macropore flow. These data demonstrate that Ksin coastal floodplain sulfuric horizons can be very high and is extremely variable within individual floodplains. These findings highlight the need for site specific assessments of soil hydraulic properties in CASS in order to ensure appropriate design and application of acid management techniques. © 2009 Elsevier B.V. All rights reserved.

DOI 10.1016/j.geoderma.2009.05.010
Citations Scopus - 30
2009 Johnston SG, Burton ED, Keene AF, Bush RT, Sullivan LA, Isaacson L, 'Pore water sampling in acid sulfate soils: A new peeper method', Journal of Environmental Quality, 38 2474-2477 (2009)

This study describes the design, deployment, and application of a modified equilibration dialysis device (peeper) optimized for sampling pore waters in acid sulfate soils (ASS). T... [more]

This study describes the design, deployment, and application of a modified equilibration dialysis device (peeper) optimized for sampling pore waters in acid sulfate soils (ASS). The modified design overcomes the limitations of traditional-style peepers, when sampling firm ASS materials over relatively large depth intervals. The new peeper device uses removable, individual cells of 25 mL volume housed in a 1.5 m long rigid, high-density polyethylene rod. The rigid housing structure allows the device to be inserted directly into relatively firm soils without requiring a supporting frame. The use of removable cells eliminates the need for a large glove-box after peeper retrieval, thus simplifying physical handling. Removable cells are easily maintained in an inert atmosphere during sample processing and the 25-mL sample volume is sufficient for undertaking multiple analyses. A field evaluation of equilibration times indicates that 32 to 38 d of deployment was necessary. Overall, the modified method is simple and effective and well suited to acquisition and processing of redox-sensitive pore water profiles > 1 m deep in acid sulfate soil or any other firm wetland soils. Copyright © 2009 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

DOI 10.2134/jeq2009.0135
Citations Scopus - 8
2009 Johnston SG, Bush RT, Sullivan LA, Burton ED, Smith D, Martens MA, et al., 'Changes in water quality following tidal inundation of coastal lowland acid sulfate soil landscapes', Estuarine, Coastal and Shelf Science, 81 257-266 (2009)

This study examines the remediation of surface water quality in a severely degraded coastal acid sulfate soil landscape. The remediation strategy consisted of partial restoration ... [more]

This study examines the remediation of surface water quality in a severely degraded coastal acid sulfate soil landscape. The remediation strategy consisted of partial restoration of marine tidal exchange within estuarine creeks and incremental tidal inundation of acidified soils, plus strategic liming of drainage waters. Time-series water quality and climatic data collected over 5 years were analysed to assess changes in water quality due to this remediation strategy. A time-weighted rainfall function (TWR) was generated from daily rainfall data to integrate the effects of antecedent rainfall on shallow groundwater levels in a way that was relevant to acid export dynamics. Significant increases in mean pH were evident over time at multiple monitoring sites. Regression analysis at multiple sites revealed a temporal progression of change in significant relationships between mean daily electrical conductivity (EC) vs. mean daily pH, and TWR vs. mean daily pH. These data demonstrate a substantial decrease over time in the magnitude of creek acidification per given quantity of antecedent rainfall. Data also show considerable increase in soil pH (2-3 units) in formerly acidified areas subject to tidal inundation. This coincides with a decrease in soil pe, indicating stronger reducing conditions. These observations suggest a fundamental shift has occurred in sediment geochemistry in favour of proton-consuming reductive processes. Combined, these data highlight the potential effectiveness of marine tidal inundation as a landscape-scale acid sulfate soil remediation strategy. © 2008 Elsevier Ltd. All rights reserved.

DOI 10.1016/j.ecss.2008.11.002
Citations Scopus - 43
2009 Isaacson LS, Burton ED, Bush RT, Mitchell DRG, Johnston SG, Macdonald BCT, et al., 'Iron(III) accumulations in inland saline waterways, Hunter Valley, Australia: Mineralogy, micromorphology and pore-water geochemistry', Applied Geochemistry, 24 1825-1834 (2009)

Discharge of Fe(II)-rich groundwaters into surface-waters results in the accumulation of Fe(III)-minerals in salinized sand-bed waterways of the Hunter Valley, Australia. The obje... [more]

Discharge of Fe(II)-rich groundwaters into surface-waters results in the accumulation of Fe(III)-minerals in salinized sand-bed waterways of the Hunter Valley, Australia. The objective of this study was to characterise the mineralogy, micromorphology and pore-water geochemistry of these Fe(III) accumulations. Pore-waters had a circumneutral pH (6.2-7.2), were sub-oxic to oxic (Eh 59-453 mV), and had dissolved Fe(II) concentrations up to 81.6 mg L-1. X-ray diffraction (XRD) on natural and acid-ammonium-oxalate (AAO) extracted samples indicated a dominance of 2-line ferrihydrite in most samples, with lesser amounts of goethite, lepidocrocite, quartz, and alumino-silicate clays. The majority of Fe in the samples was bound in the AAO extractable fraction (FeOx) relative to the Na-dithionite extractable fraction (FeDi), with generally high FeOx:FeDi ratios (0.52-0.92). The presence of nano-crystalline 2-line ferrihydrite (Fe5HO3·4H2O) with lesser amounts of goethite (a-FeOOH) was confirmed by scanning electron microscopy (SEM) coupled with energy dispersive X-ray analysis (EDX), and transmission electron microscopy (TEM) coupled with selected area electron diffraction (SAED). In addition, it was found that lepidocrocite (¿-FeOOH), which occurred as nanoparticles as little as ~5 lattice spacings thick perpendicular to the (0 2 0) lattice plane, was also present in the studied Fe(III) deposits. Overall, the results highlight the complex variability in the crystallinity and particle-size of Fe(III)-minerals which form via oxidation of Fe(II)-rich groundwaters in sand-bed streams. This variability may be attributed to: (1) divergent precipitation conditions influencing the Fe(II) oxidation rate and the associated supply and hydrolysis of the Fe(III) ion, (2) the effect of interfering compounds, and (3) the influence of bacteria, especially Leptothrix ochracea. © 2009 Elsevier Ltd. All rights reserved.

DOI 10.1016/j.apgeochem.2009.06.004
Citations Scopus - 9
2009 Morgan KE, Burton ED, Cook P, Raven MD, Fitzpatrick RW, Bush R, et al., 'Fe and S K-edge XAS determination of iron-sulfur species present in a range of acid sulfate soils: Effects of particle size and concentration on quantitative XANES determinations', Journal of Physics: Conference Series, 190 (2009)

Acid sulfate soils (ASS) are soils and soft sediments in which sulfuric acid may be produced from iron sulfides or have been produced leaving iron oxyhydroxysulfates in amounts th... [more]

Acid sulfate soils (ASS) are soils and soft sediments in which sulfuric acid may be produced from iron sulfides or have been produced leaving iron oxyhydroxysulfates in amounts that have a long lasting effect on soil characteristics. If soil material is exposed to rotting vegetation or other reducing material, the Fe-oxyhydroxysulfates can be bacterially reduced to sulfides including disulfides (pyrite and marcasite), and Monosulfidic Black Ooze (MBO) a poorly characterised material known to be a mixture of iron sulfides (especially mackinawite) and organic matter. The chemistry of these environments is strongly affected by Fe and S cycling processes and herein we have sought to identify key differences in environments that occur as a function of Fe and S concentration. In addition to our chemical results, we have found that the effects of particle size on self absorption in natural sediments play an important role in the spectroscopic identification of the relative proportions of different species present. © 2009 IOP Publishing Ltd.

DOI 10.1088/1742-6596/190/1/012144
Citations Scopus - 4
2009 Erskine WD, Chalmers AC, Keene A, Cheetham M, Bush R, 'Role of a rheophyte in bench development on a sand-bed river in southeast Australia', Earth Surface Processes and Landforms, 34 941-953 (2009) [C1]
DOI 10.1002/esp.1778
Citations Scopus - 26Web of Science - 24
Co-authors Anita Chalmers
2008 Burton ED, Bush RT, Sullivan LA, Johnston SG, Hocking RK, 'Mobility of arsenic and selected metals during re-flooding of iron- and organic-rich acid-sulfate soil', Chemical Geology, 253 64-73 (2008)

The drainage-induced oxidation of iron-sulfide minerals in acid-sulfate soils has adversely affected large areas of coastal floodplains. Re-flooding of these soils, via the re-est... [more]

The drainage-induced oxidation of iron-sulfide minerals in acid-sulfate soils has adversely affected large areas of coastal floodplains. Re-flooding of these soils, via the re-establishment of more natural drainage regimes, is a potential remediation approach. Here we describe the mobility of Al, As, Fe, Mn, Ni and Zn during controlled re-flooding of an Fe- and organic-rich acid-sulfate soil material. Soil re-flooding caused the onset of microbially-mediated Fe(III)-reduction, which raised the pH of the initially acidic (pH 3.4) soil to pH 6.0 to 6.5, thereby immobilizing Al. The process of Fe(III)-reduction released high concentrations of FeIIand was associated with significant mobilization of As. During the early stages of re-flooding, FeIImobility was controlled by dissolution of schwertmannite (Fe8O8(OH)6SO4) with an ion activity product (IAP) of 1019 ± 2. The mobility of FeIIwas subsequently controlled by the precipitation of siderite (FeCO3) with an IAP spanning 10- 10to 10- 7.5. The formation of acid-volatile sulfide (AVS), as a product of SO4-reduction, further retarded the mobility of FeII. Interactions with AVS also strongly immobilized Mn, Ni and Zn, yet had little effect on As which remained relatively mobile in the re-flooded soil. This study shows that the mobilization of As and Fe during soil re-flooding should be considered when planning remediation approaches for acid-sulfate soils. © 2008 Elsevier B.V. All rights reserved.

DOI 10.1016/j.chemgeo.2008.04.006
Citations Scopus - 103
2008 Burton ED, Bush RT, Sullivan LA, Mitchell DRG, 'Schwertmannite transformation to goethite via the Fe(II) pathway: Reaction rates and implications for iron-sulfide formation', Geochimica et Cosmochimica Acta, 72 4551-4564 (2008)

Schwertmannite (Fe8O8(OH)6SO4) is a common Fe(III)-oxyhydroxysulfate mineral in acid-sulfate systems, where its formation and fate strongly influence water quality. The present st... [more]

Schwertmannite (Fe8O8(OH)6SO4) is a common Fe(III)-oxyhydroxysulfate mineral in acid-sulfate systems, where its formation and fate strongly influence water quality. The present study examines transformation of schwertmannite to goethite (FeOOH), as catalyzed by interactions with Fe(II) in anoxic aquatic environments. This study also evaluates the role of the Fe(II) pathway in influencing the formation of iron-sulfide minerals in such environments. At pH > 5, the rates of Fe(II)-catalyzed schwertmannite transformation were several orders of magnitude faster than transformation in the absence of Fe(II). Complete transformation of schwertmannite occurred within only 3-5 h at pH > 6 and Fe(II)(aq) = 5 mmol L-1. Model calculations indicate that the Fe(II)-catalyzed transformation of schwertmannite to goethite greatly decreases the reactivity of the Fe(III) pool, thereby favoring SO4-reduction and facilitating the formation of iron-sulfide minerals (particularly mackinawite, tetragonal FeS). Examination of in situ sediment geochemistry in an acid-sulfate system revealed that the rapid Fe(II)-catalyzed transformation was consistent with an abrupt shift from an acidic Fe(III)-reducing regime with abundant schwertmannite near the sediment surface, to a near-neutral mackinawite-forming regime where goethite was dominant. This study demonstrates that the Fe(II) pathway exerts a major influence on schwertmannite transformation and iron-sulfide formation in anoxic acid-sulfate systems. These findings have important implications for understanding acidity dynamics and trace element mobility in such systems. © 2008 Elsevier Ltd. All rights reserved.

DOI 10.1016/j.gca.2008.06.019
Citations Scopus - 100
2008 Burton ED, Sullivan LA, Bush RT, Powell B, 'Iron-sulfide and trace element behaviour in sediments of Coombabah Lake, southern Moreton Bay (Australia)', Marine Pollution Bulletin, 56 1353-1358 (2008)
DOI 10.1016/j.marpolbul.2008.04.012
Citations Scopus - 12
2008 Burton ED, Sullivan LA, Bush RT, Johnston SG, Keene AF, 'A simple and inexpensive chromium-reducible sulfur method for acid-sulfate soils', Applied Geochemistry, 23 2759-2766 (2008)

A new chromium-reducible sulfur (CRS) method suitable for the quantification of reduced inorganic S (RIS) in acid-sulfate soils is presented. The new method utilises the reduction... [more]

A new chromium-reducible sulfur (CRS) method suitable for the quantification of reduced inorganic S (RIS) in acid-sulfate soils is presented. The new method utilises the reduction of RIS by an acidic Cr(II) solution within a sealed reaction chamber and diffusion of the produced H2S(g)into an alkaline Zn solution. It offers rapid sample processing times, without the need for large volumes of high-purity N2(g)or for specialized, expensive glassware. Examination of pyrite-talc mixtures containing up to 11.8% pyrite, revealed that the method achieves 95-98% recovery of RIS. A comparison between CRS measured by the new diffusion-based method and that measured by a standard purge-and-trap method for 25 pyritic soil samples shows a very strong (r2= 0.996) linear relationship with a slope of 0.995. The ability of the new diffusion-based CRS method to achieve accurate and precise quantification of RIS in acid-sulfate soils is demonstrated. © 2008 Elsevier Ltd. All rights reserved.

DOI 10.1016/j.apgeochem.2008.07.007
Citations Scopus - 82
2008 McGrath RJ, Boyd WE, Bush RT, 'The paleohydrological context of the iron age floodplain sites of the Mun River Valley, Northeast Thailand', Geoarchaeology, 23 151-172 (2008)

Many Iron Age sites on the flood plain of the Mun River in northeast Thailand are encircled by channels commonly known as &quot;moats.&quot; Also, the sites are closely associated... [more]

Many Iron Age sites on the flood plain of the Mun River in northeast Thailand are encircled by channels commonly known as "moats." Also, the sites are closely associated with complex paleochannels of the river. A comparison between the seemingly human-constructed moats and paleochannels provided an opportunity to assess the relationship between prehistoric human settlement and paleohydrological conditions. In this study, the results of physical, sedimentological, and geochemical analyses are used to characterize sediments deposited within the channels around the Iron Age site of Ban Non Wat and within a paleochannel at nearby Ban Non Ngiu. This allowed us to test the results of previous research that has suggested significant changes in the floodplain hydrology and the geoarchaeologically important conclusion that Iron Age human activity was associated with one particular paleohydrological phase. Our analyses broadly confirm the results of previous stratigraphic studies, but add detail regarding sedimentation processes. The evidence indicates that there are significant sedimentological differences within the complex of archaeological channel features, differences that provide critical evidence for the formation and sedimentation processes of the channels. More importantly, comparison between the archaeological features and the natural channel fills highlights the relationships between the archaeological sites and landscape. Drawing also on previously published chronological, geomorphological, and stratigraphical data, it is possible to place the sites into a floodplain hydrological regime that may have been unique to the Iron Age. Specifically, the moats may have been constructed in response to enhanced water availability on the floodplain. The sites, therefore, may reflect a human response to increased availability of water beyond the main river channels. This water supply, however, appears to have been short-lived (centuries at most), and with its loss, the human adaptation to this enhanced natural resource became unviable. © 2008 Wiley Periodicals, Inc.

DOI 10.1002/gea.20210
Citations Scopus - 13
2008 Cheetham MD, Keene AF, Bush RT, Sullivan LA, Erskine WD, 'A comparison of grain-size analysis methods for sand-dominated fluvial sediments', Sedimentology, 55 1905-1913 (2008) [C1]
DOI 10.1111/j.1365-3091.2008.00972.x
Citations Scopus - 29Web of Science - 22
2007 Burton ED, Bush RT, Sullivan LA, Mitchell DRG, 'Reductive transformation of iron and sulfur in schwertmannite-rich accumulations associated with acidified coastal lowlands', Geochimica et Cosmochimica Acta, 71 4456-4473 (2007)

We examined the transformations of Fe and S associated with schwertmannite (Fe8O8(OH)6SO4) reduction in acidified coastal lowlands. This was achieved by conducting a 91 day diffus... [more]

We examined the transformations of Fe and S associated with schwertmannite (Fe8O8(OH)6SO4) reduction in acidified coastal lowlands. This was achieved by conducting a 91 day diffusive-flux column experiment, which involved waterlogging of natural schwertmannite- and organic-rich soil material. This experiment was complemented by short-term batch experiments utilizing synthetic schwertmannite. Waterlogging readily induced bacterial reduction of schwertmannite-derived Fe(III), producing abundant pore-water FeII, SO4and alkalinity. Production of alkalinity increased pH from pH 3.4 to pH ~6.5 within the initial 14 days, facilitating the precipitation of siderite (FeCO3). Interactions between schwertmannite and FeIIat pH ~6.5 were found, for the first time, to catalyse the transformation of schwertmannite to goethite (aFeOOH). Thermodynamic calculations indicate that this FeII-catalysed transformation shifted the biogeochemical regime from an initial dominance of Fe(III)-reduction to a subsequent co-occurrence of both Fe(III)- and SO4-reduction. This lead firstly to the formation of elemental S via H2S oxidation by goethite, and later also to formation of nanoparticulate mackinawite (FeS) via H2S precipitation with FeII. Pyrite (FeS2) was a quantitatively insignificant product of reductive Fe and S mineralization. This study provides important new insights into Fe and S geochemistry in settings where schwertmannite is subjected to reducing conditions. © 2007 Elsevier Ltd. All rights reserved.

DOI 10.1016/j.gca.2007.07.007
Citations Scopus - 110
2006 Burton ED, Bush RT, Sullivan LA, 'Reduced inorganic sulfur speciation in drain sediments from acid sulfate soil landscapes', Environmental Science and Technology, 40 888-893 (2006)

We examined processes regulating reduced inorganic sulfur (RIS) speciation in drain sediments from coastal acid sulfate soil (ASS) landscapes. Pore water sulfide was undetectable ... [more]

We examined processes regulating reduced inorganic sulfur (RIS) speciation in drain sediments from coastal acid sulfate soil (ASS) landscapes. Pore water sulfide was undetectable or present at low levels (0.6-18.8 µM), consistent with FeS(s) precipitation in the presence of high concentrations of Fe2+ (generally >2 mM). Acid-volatile sulfide (AVS), with concentrations up to 1019 µmol g-1, comprised a major proportion of RIS. The AVS to pyrite-S ratios were up to 2.6 in sediment profiles containing abundant reactive Fe (up to ~4000 µmol g-1). Such high AVS:pyrite-S ratios are indicative of inefficient conversion of FeS (s) to pyrite. This may be due to low pore water sulfide levels causing slow rates of pyrite formation via the polysulfide and H2S oxidation pathways. Overall, RIS speciation in ASS-associated drain sediments is unique and is largely regulated by abundant reactive Fe. © 2006 American Chemical Society.

DOI 10.1021/es0516763
Citations Scopus - 48
2006 Burton ED, Bush RT, Sullivan LA, 'Acid-volatile sulfide oxidation in coastal flood plain drains: Iron-sulfur cycling and effects on water quality', Environmental Science and Technology, 40 1217-1222 (2006)

The effect of acid-volatile sulfide (AVS) oxidation on Fe-S cycling and water quality in coastal flood plain drains from acid-sulfate soil landscapes was examined using natural se... [more]

The effect of acid-volatile sulfide (AVS) oxidation on Fe-S cycling and water quality in coastal flood plain drains from acid-sulfate soil landscapes was examined using natural sediments and synthetic iron monosulfide. Oxidation of AVS occurred rapidly (half-time = 1 h) and produced elemental sulfur (S80(s)) and iron oxyhydroxide (FeOOH (s)). The initial rapid AVS oxidation process occurred without significant acidification or changes to the aqueous-phase composition. Severe acidification (pH < 4) occurred only once S80(s) began to oxidize to SO4 (within 2-3 days of the initial AVS oxidation). Our results demonstrate, for the first time with natural sediments, a significant pH-buffered (near-neutral) AVS oxidation step with the trigger to acidification being the oxidation of S80(s). Acidification resulted in the pH-dependent release of large amounts of Al, Mn, Ni, and Zn even though the sediment metal content was low. © 2006 American Chemical Society.

DOI 10.1021/es0520058
Citations Scopus - 80
2006 Burton ED, Bush RT, Sullivan LA, 'Sedimentary iron geochemistry in acidic waterways associated with coastal lowland acid sulfate soils', Geochimica et Cosmochimica Acta, 70 5455-5468 (2006)

We examined the solubility, mineralogy and geochemical transformations of sedimentary Fe in waterways associated with coastal lowland acid sulfate soils (CLASS). The waterways con... [more]

We examined the solubility, mineralogy and geochemical transformations of sedimentary Fe in waterways associated with coastal lowland acid sulfate soils (CLASS). The waterways contained acidic (pH 3.26-3.54), FeIII-rich (27-138 µM) surface water with low molar Cl:SO4ratios (0.086-5.73). The surficial benthic sediments had high concentrations of oxalate-extractable Fe(III) due to schwertmannite precipitation (kinetically favoured by 28-30% of aqueous surface water Fe being present as the FeIIISO4+species). Subsurface sediments contained abundant pore-water HCO3(6-20 mM) and were reducing (Eh < -100 mV) with pH 6.0-6.5. The development of reducing conditions caused reductive dissolution of buried schwertmannite and goethite (formed via in situ transformation of schwertmannite). As a consequence, pore-water FeIIconcentrations were high (>2 mM) and were constrained by precipitation-dissolution of siderite. The near-neutral, reducing conditions also promoted SO4-reduction and the formation of acid-volatile sulfide (AVS). The results show, for the first time for CLASS-associated waterways, that sedimentary AVS consisted mainly of disordered mackinawite. In the presence of abundant pore-water FeII, precipitation-dissolution of disordered mackinawite maintained very low (i.e. <0.1 µM) S-IIconcentrations. Such low concentrations of S-IIcaused slow rates for conversion of disordered mackinawite to pyrite, thereby resulting in relatively low concentrations of pyrite (<300 µmol g-1as Fe) compared to disordered mackinawite (up to 590 µmol g-1as Fe). This study shows that interactions between schwertmannite, goethite, siderite, disordered mackinawite and pyrite control the geochemical behaviour of sedimentary Fe in CLASS-associated waterways. © 2006 Elsevier Inc. All rights reserved.

DOI 10.1016/j.gca.2006.08.016
Citations Scopus - 92
2006 Burton ED, Bush RT, Sullivan LA, 'Fractionation and extractability of sulfur, iron and trace elements in sulfidic sediments', Chemosphere, 64 1421-1428 (2006)

This study describes iron and sulfur fractionation, and the related extractability of selected trace elements (As, Cd, Cr, Cu, Ni, Pb and Zn) in estuarine sediments. The sediments... [more]

This study describes iron and sulfur fractionation, and the related extractability of selected trace elements (As, Cd, Cr, Cu, Ni, Pb and Zn) in estuarine sediments. The sediments were sulfidic, with moderately high concentrations of pore-water sulfide (200-600 µmol l-1) and acid-volatile sulfide (AVS; 9.9-129 µmol g-1). Pyrite-S concentrations increased with depth, with 63-251 µmol g-1at site W1 and 312-669 µmol g-1at site W2. The degree of sulfidisation was generally high (>80%), indicating that Fe may be limiting pyrite accumulation. The ratios of AVS to pyrite-S increased with sediment depth, as expected for the pyritisation of solid-phase AVS. Cadmium, Pb and Zn extractability in 1 M HCl indicated that these elements are not significantly sequestered during pyritisation, whereas sequestration may be important for As, Cu and possibly Ni. Extractability trends for Cr suggest that diagenesis in sulfidic sediments may enhance Cr reactivity. Overall, replacement of AVS by pyrite during diagenesis may enhance the reactivity of Cd, Cr, Pb and Zn, whereas As, Cu and possibly Ni may be rendered less reactive. © 2005 Elsevier Ltd. All rights reserved.

DOI 10.1016/j.chemosphere.2005.12.003
Citations Scopus - 57
2006 Burton ED, Bush RT, Sullivan LA, 'Elemental sulfur in drain sediments associated with acid sulfate soils', Applied Geochemistry, 21 1240-1247 (2006)

This paper reports the abundance of elemental S in drain sediments associated with acid sulfate soils. The sediments exhibited near-neutral pH (5.97-7.27), high concentrations of ... [more]

This paper reports the abundance of elemental S in drain sediments associated with acid sulfate soils. The sediments exhibited near-neutral pH (5.97-7.27), high concentrations of pore-water Fe2+(1.37-15.9 mM) and abundant oxalate-extractable Fe (up to 4300 µmol g-1). Maximum acid-volatile sulfide (AVS) concentrations in each sediment profile were high (118-1019 µmol g-1), with AVS often exceeding pyrite-S. Elemental S occurred at concentrations of 13-396 µmol g-1, with the higher concentrations exceeding previous concentrations reported for other sedimentary systems. Up to 62% of reduced inorganic S near the sediment/water interface was present as elemental S, due to reaction between AVS and oxidants such as O2and Fe(III). Significant correlation (r = 0.74; P < 0.05) between elemental S and oxalate-extractable Fe(III) is indicative of elemental S formation by in situ oxidation of AVS. The results indicate that AVS oxidation in near-surface sediments is dynamic in acidified coastal floodplain drains, causing elemental S to be a quantitatively important intermediate S fraction. Transformations of elemental S may therefore strongly influence water quality in ASS landscapes. © 2006 Elsevier Ltd. All rights reserved.

DOI 10.1016/j.apgeochem.2006.02.020
Citations Scopus - 37
2004 Ward NJ, Sullivan LA, Fyfe DM, Bush RT, Ferguson AJP, 'The process of sulfide oxidation in some acid sulfate soil materials', Australian Journal of Soil Research, 42 449-458 (2004)

The process of sulfide oxidation in acid sulfate soils (ASS) is complex, involving the formation of numerous oxidation products. In this study the sulfide oxidation process was ex... [more]

The process of sulfide oxidation in acid sulfate soils (ASS) is complex, involving the formation of numerous oxidation products. In this study the sulfide oxidation process was examined in 2 ASS materials over a period of 36 days using laboratory incubation experiments. Both ASS materials experienced substantial sulfide oxidation and acidification during incubation. The oxidation of pyrite was the primary cause of acidification in these ASS materials. Although a decrease in magnetic susceptibility (¿) over the initial 4 days of incubation suggested the rapid oxidation of ferromagnetic iron monosulfide greigite (Fe3S4), the total acid volatile sulfur (S AV) fraction increased in concentration by an order of magnitude over the initial 8 days of incubation. Oxygen (O2) concentration profiles indicated the presence of anoxic conditions in the centre of the incubating materials even after 16 days of exposure to the atmosphere enabling S AV formation to occur. The oxidation of the SAV fraction did not result in substantial acidification. A large proportion of the water-soluble iron released by sulfide oxidation was precipitated as iron oxides and hydroxides. Sulfate (SO42-) was the dominant sulfur species produced from sulfide oxidation in both ASS materials, although water-soluble SO42- was a poor indicator of the extent of sulfide oxidation. The sulfoxyanion intermediates, thiosulfate (S 2O32-) and tetrathionate (S4O 62-), were detected only in the early stages of incubation, with minimal amounts being detected after the initial 4 days. The relative abundance of these 2 intermediate sulfur species appeared to be dependent on the soil pH, with S4O62- dominating S2O32- in the more acidic ASS material (i.e. pH <6) as has been observed in previous studies. The diminishing presence of sulfoxyanion intermediates as oxidation progressed was indicative that ferric ion (Fe3+) and bacterial catalysis were driving the oxidation processes. While these sulfoxyanion intermediates only constituted a small percentage of the reduced inorganic sulfur (RIS) fraction, they accounted for up to 9.3% of the total soluble sulfur fraction. Elemental sulfur (S0) was not an important sulfide oxidation product in the ASS materials examined in this study.

DOI 10.1071/SR03135
Citations Scopus - 23
2004 Ward NJ, Sullivan LA, Bush RT, 'The response of partially oxidised acid sulfate soil materials to anoxia', Australian Journal of Soil Research, 42 515-525 (2004)

Four acid sulfate soil (ASS) materials were subjected to anoxia after varying periods of oxidation to determine the geochemical response of these types of soils to flooding. The r... [more]

Four acid sulfate soil (ASS) materials were subjected to anoxia after varying periods of oxidation to determine the geochemical response of these types of soils to flooding. The response of the partially oxidised ASS materials to the exclusion of oxygen was variable. The rate of sulfide oxidation, acidification, and the production of soluble oxidation products such as sulfate, iron, and aluminium generally decreased markedly when subjected to anoxia. However, especially in the highly acidic ASS materials (i.e. pH <3.5), sulfide oxidation and acidification generally continued (albeit at much slower rates), most probably due to oxidation by Fe3+. Rapid sulfide re-formation occurred in the peat ASS material that had been oxidised for 63 days, with 0.47% reduced inorganic sulfur (SCR) formed over 60 days of anoxia. This substantial sulfide re-formation was accompanied by only a slight increase in pH. Minimal sulfide re-formation occurred in 2 of the ASS materials when placed in anoxic conditions, most likely due to a lack of readily available organic matter in these materials. The results show that the imposition of anoxic conditions on partially oxidised ASS materials is generally effective in decreasing the rates of further sulfide oxidation, acidification, and the production of soluble sulfide oxidation products. Biogeochemical sulfide formation consumes acidity; however, sulfide re-formation was ineffective in reversing acidification under the conditions of this experiment. The results indicate that the treatment of sites containing actual ASS materials by management strategies relying on oxygen exclusion need to be accompanied by other strategies that include acidity neutralisation or containment.

Citations Scopus - 7
2004 Bush RT, Fyfe D, Sullivan LA, 'Occurrence and abundance of monosulfidic black ooze in coastal acid sulfate soil landscapes', Australian Journal of Soil Research, 42 609-616 (2004)

Organic oozes enriched in iron monosulfides are called monosulfidic black ooze (MBO). The occurrence and abundance of MBO were quantified in natural tributaries and man-made drain... [more]

Organic oozes enriched in iron monosulfides are called monosulfidic black ooze (MBO). The occurrence and abundance of MBO were quantified in natural tributaries and man-made drainage canals on a typical coastal river floodplain. Thick deposits of MBO occurred in drains and the protected upper reaches of tributaries in acid sulfate soil (ASS) areas. Acid-tolerant lilies grew prolifically in these areas, contributing large amounts of decaying organic debris. The MBO contained up to 6.3% acid-volatile sulfur (equivalent to 18% iron monosulfide), an order of magnitude greater than reported previously for natural sediments. It also contained up to 6% pyritic sulfur (equivalent to approximately 11% pyrite). Sulfate and iron from surrounding ASS combined with abundant organic matter and protected flow in ASS drains provide excellent conditions for sulfate reduction, leading to iron sulfide precipitation and the accumulation of organic detritus. When mixed with water, the iron monosulfide in MBO can react within minutes to completely consume dissolved oxygen. There are thousands of drains in ASS areas that may have thick deposits of MBO. The MBO has the potential to cause rapid and severe effects on water quality. The challenge is to develop management practices that reduce the formation and accumulation of MBO in acid sulfate landscapes.

Citations Scopus - 39
2004 Ward NJ, Sullivan LA, Bush RT, 'Soil pH, oxygen availability, and the rate of sulfide oxidation in acid sulfate soil materials: Implications for environmental hazard assessment', Australian Journal of Soil Research, 42 509-514 (2004)

The potential environmental hazard of acid sulfate soil (ASS) materials is directly related to both the net acidity and the rate that actual acidity is released from these soil ma... [more]

The potential environmental hazard of acid sulfate soil (ASS) materials is directly related to both the net acidity and the rate that actual acidity is released from these soil materials into the environment. While current environmental hazard assessment techniques for ASS materials are able to quantify the net acidity, they do not take account of differences in the rate of sulfide oxidation (the dominant source of actual acidity) and differences in the rate of acidification. In this study the rate of sulfide oxidation during incubation was examined for 4 ASS materials. The effect of pH and oxygen availability on the rate of sulfide oxidation was assessed. The ASS materials were incubated in: (i) gauze where oxygen diffusion was not restricted, and (ii) sealed 100-µm-thick plastic bags which greatly limited oxygen diffusion. When oxygen diffusion was not restricted, an accelerated oxidation of sulfide occurred when the pH decreased below pH 4.0. The accelerated rate of sulfide oxidation at such low pH did not occur when oxygen diffusion was limited. This study indicates that the initial pH of an ASS material is a useful additional indicator of the potential environmental hazard of an ASS material when oxygen is expected to be non-limiting, such as when ASS materials are excavated and stockpiled. The recommended action criteria need to be reassessed, as the data indicate that the current criteria are conservative for alkaline and neutral ASS materials, but should be lowered for all acidic ASS materials (i.e. pH <5.5) to 0.03% sulfide regardless of texture.

Citations Scopus - 18
2004 Bush RT, Sullivan LA, Fyfe D, Johnston S, 'Redistribution of monosulfidic black oozes by floodwaters in a coastal acid sulfate soil floodplain', Australian Journal of Soil Research, 42 603-607 (2004)

The observations presented in this paper illustrate that significant amounts of monosulfidic black oozes (MBO) were eroded from flood mitigation drainage canals and redistributed ... [more]

The observations presented in this paper illustrate that significant amounts of monosulfidic black oozes (MBO) were eroded from flood mitigation drainage canals and redistributed across a coastal floodplain during a flood event associated with extreme deoxygenation and a massive fish kill. MBO are organic materials enriched in iron monosulfides and thick layers can accumulate in drains affected by acid sulfate soils. Laboratory studies have demonstrated that MBO can react rapidly when brought into suspension to completely consume dissolved oxygen. The abundance of MBO in flood mitigation drains and their extreme reactivity implicated MBO in the acute deoxygenation of the Richmond River, north-eastern New South Wales, Australia, following a major flood in February 2001. The field observations of MBO redistribution provide valuable evidence to help explain how these materials may interact and contribute to the deoxygenation of floodwaters.

Citations Scopus - 18
2004 Bush RT, McGrath R, Sullivan LA, 'Occurrence of marcasite in an organic-rich Holocene estuarine mud', Australian Journal of Soil Research, 42 617-621 (2004)

Substantial marcasite and pyrite were recently identified in the upper-most unoxidised Holocene clay-peat sediments at Bungawalbin Swamp, a coastal backswamp on the Richmond River... [more]

Substantial marcasite and pyrite were recently identified in the upper-most unoxidised Holocene clay-peat sediments at Bungawalbin Swamp, a coastal backswamp on the Richmond River floodplain, north-east New South Wales, Australia. Marcasite (FeS2), the mineral dimorph of pyrite, is considered a rare secondary mineral in estuarine sediments and its abundance at Bungawalbin Swamp is highly unusual. The morphology and distribution of marcasite in the sulfidic sedimentary profile was examined and compared with the palynological record. Marcasite, recognised by its distinctive platy morphology and disulfide composition, occurred exclusively within organic remnants in only the upper most 1 m of the sulfidic sediment layer. Pyrite occurred throughout the sulfidic profile. A dramatic change in the sedimentary conditions at Bungawalbin Swamp from a marine environment, characterised by the presence of avicenniaceae (i.e. mangrove), to a fresh-brackish environment correlates directly with the occurrence of marcasite. The occurrence of substantial marcasite may provide a valuable environmental proxy of fresh-brackish depositional swamp environments.

Citations Scopus - 15
2004 Sullivan LA, Bush RT, 'Iron precipitate accumulations associated with waterways in drained coastal acid sulfate landscapes of eastern Australia', Marine and Freshwater Research, 55 727-736 (2004)

Iron precipitate accumulations from surface environments surrounding waterways (such as the side of drains and soil surface horizons) in acid sulfate soil landscapes were analysed... [more]

Iron precipitate accumulations from surface environments surrounding waterways (such as the side of drains and soil surface horizons) in acid sulfate soil landscapes were analysed for their mineralogy, micromorphology and chemical properties. Schwertmannite (Fe8(OH)5.5(SO 4)1.25) was the dominant mineral in these accumulations. Goethite (a-FeOOH) was the other iron precipitate mineral identified in these accumulations and the data indicate that this iron mineral was formed from schwertmannite, often as pseudomorphs after schwertmannite. The schwertmannite in these accumulations had similar morphology and chemical properties to schwertmannite reported for environments affected by acid mine drainage. The activity of Fe3+ in the drainage waters in these landscapes appears to be controlled by schwertmannite during both low flow (dry season) and flood conditions. Iron precipitate accumulations contained appreciable amounts of stored acidity (i.e. titratable actual acidity of between 164 and 443 mol (H+) t-1, and 1900 to 2580 mol (H+) t -1 of schwertmannite upon complete conversion to goethite) that tends to buffer these waters to very acidic conditions (i.e. pHs~3.0-3.5). The relationship between water quality (i.e. pH and sulfate concentration) and type of iron precipitate mineral formed should enable the mineralogy of the iron precipitates in these surface environments to be used to help identify the degree of severity of degradation in these acid sulfate soil landscapes and to monitor the effectiveness of remediation programmes.

DOI 10.1071/MF04072
Citations Scopus - 65
2002 Ward NJ, Sullivan LA, Bush RT, Lin C, 'Assessment of peroxide oxidation for acid sulfate soil analysis. 1. Reduced inorganic sulfur', Australian Journal of Soil Research, 40 433-442 (2002)

The reduced inorganic sulfur fraction of 4 acid sulfate soil (ASS) materials was quantified using a variety of peroxide oxidation procedures. The temperature and duration of the p... [more]

The reduced inorganic sulfur fraction of 4 acid sulfate soil (ASS) materials was quantified using a variety of peroxide oxidation procedures. The temperature and duration of the peroxide oxidation were found to markedly affect the peroxide oxidisable sulfur determination. For 3 ASS materials with low total carbon content (i.e. <2.5% C), peroxide oxidisable sulfur underestimated the reduced inorganic sulfur fraction, with the peroxide oxidisable sulfur determinations being as low as 42% of those determined using chromium reducible sulfur technique. The precipitation of jarosite during peroxide oxidation was a major factor contributing to the underestimation of reduced inorganic sulfur in these materials. Apparent losses of sulfur of approximately 25% on average occurred during peroxide oxidation budget accounting; this also contributed towards the observed underestimation of reduced inorganic sulfur. It is most likely that these unaccounted losses are due to atmospheric losses of sulfur. In a peat ASS, one of the peroxide oxidation methods overestimated the reduced inorganic sulfur fraction and was attributed to the release of a large reserve of organic sulfur in this material by the peroxide. This study shows the peroxide oxidation methods examined here are subject to substantial interferences. Consequently these peroxide oxidation methods are unable to reliably provide accurate measurements of the reduced inorganic sulfur fraction in ASS materials.

DOI 10.1071/SR01009
Citations Scopus - 9
2002 Ward NJ, Sullivan LA, Bush RT, Lin C, 'Assessment of peroxide oxidation for acid sulfate soil analysis. 2. Acidity determination', Australian Journal of Soil Research, 40 443-454 (2002)

Total sulfidic acidity (TSA) and total potential acidity (TPA) are derived from peroxide oxidation of acid sulfate soil materials (ASS), and are measures of the sulfidic acidity a... [more]

Total sulfidic acidity (TSA) and total potential acidity (TPA) are derived from peroxide oxidation of acid sulfate soil materials (ASS), and are measures of the sulfidic acidity and the net acidity (net acidity = sulfidic acidity + actual acidity - acid neutralising capacity), respectively. The TSA and TPA of 4 ASS materials were determined using a variety of peroxide oxidation procedures and compared with the sulfidic acidity and net acidity derived from the use of an acid-base accounting model. TSA and TPA values both varied greatly with each peroxide oxidation method used, and both measures were found to substantially underestimate (i.e. by 23-85%) both sulfidic acidity (as determined from the chromium reducible sulfur content) and net acidity (as determined by acid-base accounting). A major cause of this underestimation of acidity was the retention of acidity through the precipitation of jarosite during peroxide oxidation. Substantial clay mineral dissolution appears to have occurred during peroxide oxidation of the ASS materials, as indicated by increased soluble aluminium. Such dissolution may contribute to the underestimation of both sulfidic and net acidity for the ASS materials using peroxide oxidation methods. The loss of acidity to the atmosphere was identified as a possible additional interference. This study shows the peroxide oxidation methods examined here are subject to substantial interferences, which caused large underestimations of acidity, and consequently, are unable to reliably provide accurate measurements of sulfidic and net acidity in ASS materials.

DOI 10.1071/SR01019
Citations Scopus - 10
2002 Ward NJ, Sullivan LA, Bush RT, 'Sulfide oxidation and acidification of acid sulfate soil materials treated with CaCO

Acid sulfate soil (ASS) materials that are subject to oxidation are often treated with neutralising agents to minimise the export of acidity that may result from pyrite oxidation.... [more]

Acid sulfate soil (ASS) materials that are subject to oxidation are often treated with neutralising agents to minimise the export of acidity that may result from pyrite oxidation. The effects of additions of both CaCO3 and seawater-neutralised bauxite refinery residue (SNBRR) on the oxidation of sulfides and acidification were assessed for 4 ASS materials using laboratory incubation experiments. As the application of sub-optimal rates of neutralising materials can occur for a variety of reasons, the effect of application rates were also examined. Two application rates were chosen; a sub-optimal rate [approximately 20% of the theoretical neutralising requirement (NR)] and an excessive application rate (>250% of the NR). There was minimal sulfide oxidation and no acidification after the addition of excess CaCO3over the 180 days of incubation. The addition of excess SNBRR prevented acidification, but substantial sulfide oxidation still occurred. Following a brief initial increase in pH when sub-optimal rates of CaCO3and SNBRR were applied, the treated ASS materials rapidly acidified. For three of the ASS materials the addition of sub-optimal amounts of CaCO3had little impact on the rate of sulfide oxidation. However, for the other ASS material (a peat) both the rates of sulfide oxidation and acidification were accelerated by the addition of sub-optimal rates of CaCO3, resulting in higher soluble Fe and Al concentrations than in the untreated ASS materials. For some of the ASS materials, sub-optimal applications of SNBRR resulted in elevated soluble Al.

DOI 10.1071/SR01119
Citations Scopus - 11
2001 Lin C, Mcconchie D, Bush RT, Sullivan LA, Rosicky M, 'Characteristics of some heavy metals in acid sulfate topsoils, eastern australia', Pedosphere, 11 31-37 (2001)

Forty-five acid sulfate topsoil samples (depth &lt; 0.5 m) from 15 soil cores at 11 locations along the New South Wales coast, Australia, were selected to investigate the chemical... [more]

Forty-five acid sulfate topsoil samples (depth < 0.5 m) from 15 soil cores at 11 locations along the New South Wales coast, Australia, were selected to investigate the chemical behavior of Zn, Mn, Cr, Co and Pb in these soils. The amount of HCl-extractable Mn was much smaller than the mean value of the total Mn documented for other soils. This may be attributed to enhanced mobilization of Mn from the soils under the extremely acidic and seasonally flooded conditions encountered in the investigated soils. The pH-dependency of soluble Zn and Mn was strongly affected by the availability of acid reactive Zn and Mn compounds. There were fairly good relationships between soluble Zn and acid reactive Zn compounds, and between soluble Mn and acid reactive Mn compounds. Soluble Zn and soluble Mn concentrations were important controls on exchangeable Zn and Mn concentrations, respectively. In contrast to the suggestion by other authors that adsorption of Co was closely associated with Mn oxides present in soils, the exchangeable Co in the investigated acid sulfate soils was not clearly related to the abundance of Mn minerals. In addition to the fact that there are few Mn minerals present in the soils, this might also be because the availability of cation exchange sites on the crystal surfaces of Mn oxides was reduced under extremely acidic conditions. © 2001 SCIENCE PRESS,.

Citations Scopus - 5
2001 Lin C, Bush RT, Mcconchie D, 'Impeded acidification of acid sulfate soils in an intensively drained sugarcane land', Pedosphere, 11 209-216 (2001)

Recent research results suggest that acidification of acid sulfate soils may be inhibited in well-drained estuarine floodplains in eastern Australia by the absence of natural cree... [more]

Recent research results suggest that acidification of acid sulfate soils may be inhibited in well-drained estuarine floodplains in eastern Australia by the absence of natural creek levees. The lack of natural levees has allowed the inundation of the land by regular tidal flooding prior to the construction of flood mitigation work. Such physiographical conditions prevent the development of pre-drainage pyrite-derived soil acidification that possibly occurred at many levee-protected sites in eastern Australian estuarine floodplains during extremely dry spells. Pre-drainage acidification is considered as an important condition for accumulation of soluble Fe and consequently, the creation of favourable environments for catalysed pyrite oxidation. Under current intensively drained conditions, the acid materials produced by ongoing pyrite oxidation can be rapidly removed from soil pore water by lateral leaching and acid buffering, resulting in low concentrations of soluble Fe in the pyritic layer, which could reduce the rate of pyrite oxidation. © 2001 Science Press.

Citations Scopus - 4
2000 Bush RT, Sullivan LA, 'Iron monosulfide distribution in three coastal floodplain acid sulfate soils, eastern australia', Pedosphere, 10 237-245 (2000)

The distribution of iron monosulfide (quantified as acid volatile sulfur: SAV) was compared with geochemical properties that are known to affect its formation and accumulation in ... [more]

The distribution of iron monosulfide (quantified as acid volatile sulfur: SAV) was compared with geochemical properties that are known to affect its formation and accumulation in three coastal Holocene acid sulfate soils (ASS) at Tuckean Swamp, McLeods Creek and Bungawalbyn Swamp respectively. These properties included pH, reactive iron (Fen.), pore-water sulfate (SO42-) and organic carbon (OC). Iron monosulfide was concentrated at the oxic/anoxic boundary. The Tuckean Swamp and McLeods Creek sites are Holocene sediments, whereas the Bungawalbyn Swamp is a Holocene peat. The concentration of SAV averaged 0.2 g kg-1 in a 0.5 m thick soil layer at the Tuckean Swamp, but was an order of magnitude lower in the oxic/anoxic transition layers at McLeods Creek and Bungawalbyn Swamp. The SAV mineral greigite (FeaS,}) was identified in the Tuckean Swamp by X-ray diffraction and scanning electron microscopy with quantitative energy dispersive X-ray analysis (SEM-EDX). Very small concentrations of greigite were also observed in the McLeods Creek, based on crystal morphology and elemental composition. The concentration of SAV was a small fraction of the total reduced sulfur, representing at most 3% of the pyrite sulfur. However, the presence of this highly reactive sulfide mineral, distributed within pores where oxygen diffusion is most rapid, has important implications to the potential rate of acid production from these sediments. © 2000 SCIENCE PRESS,.

Citations Scopus - 7
2000 Sullivan LA, Bush RT, McConchie DM, 'A modified chromium-reducible sulfur method for reduced inorganic sulfur: Optimum reaction time for acid sulfate soil', Australian Journal of Soil Research, 38 729-734 (2000)

Reaction times for 16 acid sulfate soil materials analysed using a modified chromium-reducible sulfur method varied between 10 and 15 min, regardless of whether the samples had be... [more]

Reaction times for 16 acid sulfate soil materials analysed using a modified chromium-reducible sulfur method varied between 10 and 15 min, regardless of whether the samples had been dried and ground prior to analysis or were analysed without pretreatment. The reaction time for a ground (<63 µm) pyritic rock sample was 20 min. An optimum reaction time of 20 min is recommended for analysing acid sulfate soil using the modified method; this reaction time is much less than the 1 h reaction time used in previous methods.

DOI 10.1071/SR99088
Citations Scopus - 73
2000 Lin C, Islam MM, Bush RT, Sullivan LA, Melville MD, 'Acid release from an acid sulfate soil sample under successive extractions with different extractants', Pedosphere, 10 221-228 (2000)

An acid sulfate soil sample was successively extracted with deionized water, 1 mol L 1 KC1 and 0.0005 mol L-1 Ca(OH)2 solutions. The results showed that only very small amounts of... [more]

An acid sulfate soil sample was successively extracted with deionized water, 1 mol L 1 KC1 and 0.0005 mol L-1 Ca(OH)2 solutions. The results showed that only very small amounts of acidity were extracted by deionized water, possibly through slow jarosite hydrolysis. Acid release through jarosite hydrolysis was greatly enhanced by Ca(OH)2 extraction at the expense of the added OH- being neutralized by the acid released. Successive extraction of the sample with KC1 removed the largest amounts of acidity from the sample. However, it is likely that the major form of acidity released by KC1 extraction was exchangeable acidity. The results also show the occurrence of low or non charged Al and Fe species in water and Ca(OH)2 extracts after first a few extractions. It appears that such a phenomenon was related to a decreasing EC value with increasing number of extractions. © 2000 SCIENCE PRESS,.

Citations Scopus - 8
1999 Bush RT, Sullivan LA, 'Pyrite micromorphology in three Australian Holocene sediments', Australian Journal of Soil Research, 37 637-653 (1999)

The distribution and morphology of pyrite in 3 Holocene estuarine sediments were examined using light microscopy, analytical scanning electron microscopy, and X-ray diffraction. T... [more]

The distribution and morphology of pyrite in 3 Holocene estuarine sediments were examined using light microscopy, analytical scanning electron microscopy, and X-ray diffraction. The distribution and morphologies of pyrite were similar with pyrite being dispersed throughout the soil matrices as well as concentrated in root remnants and other macropores. The pyrite occurred in both framboidal and irregularly shaped dense clusters from 4 to 15 µm diameter, and also in loose clusters. Individual crystals in these clusters ranged in size from 1 to 2 µm. Pyrite crystals exhibited octahedral, pyritohedral, and equant anhedral (i.e. rounded globular) habit. Organic matter coatings and clay coatings were common around pyrite at each site. Thin coatings of monosulfide with an acicular morphology occurred around some framboidal clusters at one site. The distribution of framboids and individual crystals in the clayey matrix, root remnants, and other macropores indicates that the pyrite in these sediments has formed in situ. These data have important implications for the rate of sulfide oxidation and acid production from these soils.

Citations Scopus - 23
1999 Sullivan LA, Bush RT, McConchie D, Lancaster G, Haskins PG, Clark MW, 'Comparison of peroxide-oxidisable sulfur and chromium-reducible sulfur methods for determination of reduced inorganic sulfur in soil', Australian Journal of Soil Research, 37 255-265 (1999)

The rational management of acid sulfate soils requires analytical methods that provide reliable and accurate data on the content of reduced inorganic sulfur; it is this fraction t... [more]

The rational management of acid sulfate soils requires analytical methods that provide reliable and accurate data on the content of reduced inorganic sulfur; it is this fraction that produces acid during oxidation. This study compared the utility of the chromium-reducible sulfur method for determining the reduced inorganic sulfur content of soil materials with methods based on oxidation using hydrogen peroxide. The results presented here indicate that methods involving oxidation by hydrogen peroxide for the determination of reduced inorganic sulfur are subject to significant interference by even minor amounts of sulfate minerals and organic matter, resulting in inaccurate determinations of reduced inorganic sulfur contents. In the presence of even minor amounts of gypsum, methods involving oxidation using hydrogen peroxide underestimated reduced inorganic sulfur contents by up to 0.167% sulfur, whereas in the presence of organic matter these methods overestimated reduced inorganic sulfur contents by up to 0.077% sulfur per cent organic carbon. The resulting errors in the determinations of reduced inorganic sulfur by hydrogen peroxide methods were often larger than the action criteria that are currently used to identify acid sulfate soils. Consequently, there is a risk of misidentification of acid sulfate soils (either false positive or false negative) for soils with low reduced inorganic sulfur contents when hydrogen peroxide methods are used. In contrast, the results from the chromium-reducible sulfur method do not appear to be affected by interferences from either gypsum or organic matter and this method appears to be more suitable for the determination of reduced inorganic sulfur in soils than methods based on oxidation using hydrogen peroxide.

DOI 10.1071/S98074
Citations Scopus - 19
1997 Bush RT, Sullivan LA, 'Morphology and behaviour of greigite from a Holocene sediment in Eastern Australia', Australian Journal of Soil Research, 35 853-861 (1997)
Citations Scopus - 31
1997 Sullivan LA, Bush RT, 'Quantitative elemental microanalysis of rough-surfaced soil specimens in the scanning electron microscope using a peak-to-background method', Soil Science, 162 749-757 (1997)
Citations Scopus - 27
Show 102 more journal articles

Conference (23 outputs)

Year Citation Altmetrics Link
2012 Johnston SG, Burton ED, Keene AF, Bush RT, Sullivan LA, 'Arsenic mobilization during seawater inundation of acid sulfate soils - Hydrogeochemical coupling at the tidal fringe', Understanding the Geological and Medical Interface of Arsenic, As 2012 - 4th International Congress: Arsenic in the Environment (2012)

Coastal Acid Sulfate Soils (CASS) are rich in meta-stable iron (Fe - III) minerals that are important sorbents for arsenic (As) under oxic conditions. Tidal seawater inundation to... [more]

Coastal Acid Sulfate Soils (CASS) are rich in meta-stable iron (Fe - III) minerals that are important sorbents for arsenic (As) under oxic conditions. Tidal seawater inundation to remediate CASS has recently been trialed on a large scale and has potential to mobilize arsenic during the redox transition. Tidal seawater inundation caused reductive dissolution of As(V)-bearing Fe(III) minerals, resulting in elevated concentrations of Fe 2+ (2000 mg L -1) and As (~400 µg L -1) in upper-intertidal zone groundwater. Oscillating vertical and horizontal hydraulic gradients caused by tidal pumping promoted upward advection of As and Fe 2+-enriched groundwater within the intertidal zone. This led to flux of As aq and Fe 2+aq to surface waters and the accumulation of As(V)-enriched Fe(III) (hydr)oxides at the oxic sediment-water interface. Fe(III) (hydr)oxides at the sediment-water interface act as a natural reactive-barrier, retarding As flux to overlying surface waters. However, they also represent a highly transient phase that is prone to reductive dissolution during future redox boundary migration. A conceptual model is presented to explain landscape-scale patterns of As and Fe hydro-geochemical zonation. © 2012 Taylor & Francis Group.

2012 Keene AF, Johnston SG, Burton ED, Bush RT, Sullivan LA, 'Reductive biomineralisation of pedogenic jarosite in tidally inundated acid sulfate soils', Melbourne, Victoria (2012)
2012 Cheetham MD, Wong VNL, Bush RT, Sullivan LA, Ward NJ, 'Monosulfidic sediments in the Wakool River, Southern Australia: A preliminary investigation', Canberra, Australian Capital Territory (2012)
2011 Bush RT, 'As, Fe and S cycling during reductive biomineralisation of pedogenic jarosite', Prague, Czech Republic (2011)
2011 Burton ED, Johnston SG, Bush RT, 'The role of microbial sulfidogenesis in shaping iron-sulfurarsenic interactions within floodplain soils', Prague, Czech Republic (2011)
2010 Watling KM, Burton ED, Johnston M, Bush RT, Sullivan LA, 'Electrochemical analysis of highly reactive pyrite', ECS Transactions (2010)

Highly reactive pyritic material, exposed during the construction of the Pennsylvania Interstate Highway 99 (I-99), has been characterized by X-ray diffraction, Raman microprobe s... [more]

Highly reactive pyritic material, exposed during the construction of the Pennsylvania Interstate Highway 99 (I-99), has been characterized by X-ray diffraction, Raman microprobe spectroscopy, electron microscopy and electrochemical methods. Mineral standards of marcasite, arsenopyrite and pyrite were compared in order to determine the cause of the rapid acidification and liberation of dissolved metals observed in the exposed Pennsylvanian pyritic material. Linear sweep voltammetry found no significant differences in the electrochemical activity, however, a significantly lower open circuit potential was found in the reactive pyrite material than in the pyrite or marcasite standards. In addition to sulfur and iron, high concentrations of zinc and aluminium impurities were observed in Energy Dispersive X-ray analysis of the finest crystals of the Pennsylvanian pyritic material. © The Electrochemical Society.

DOI 10.1149/1.3367908
2010 Johnston SG, Keene AF, Bush RT, Burton ED, Sullivan LA, 'Remediating coastal acid sulfate soils by tidal inundation: geochemical hysteresis of iron', Brisbane, Australia (2010)
2010 Johnston SG, Keene AF, Bush RT, Burton ED, Sullivan LA, Wong VNL, 'Mobilisation of groundwater arsenic at the tidal fringe: hydro-geochemical coupling in seawater inundated coastal lowlands', National Convention Centre, Canberra (2010)
2010 Burton ED, Bush RT, Johnston SG, Sullivan LA, Keene AF, 'Reductive sulfur biomineralisation in a re-flooded acid-sulfate soil landscape', Brisbane, Australia (2010)
2010 Bush RT, Sullivan LA, Burton ED, Johnston SG, Keene AF, Wong V, Mosely L, 'Climate change impacts on acid sulfate soil landscapes', Knoxville, Tennessee (2010)
2010 Burton ED, Bush RT, Johnston SG, Keene AF, Sullivan LA, 'Sulfur biomineralisation across a spatio-temporal hydrogeochemical gradient in an acid sulphate soil wetland', Knoxville, Tennessee (2010)
2010 Wong VNL, Johnston SG, Hirst P, Burton ED, Bush RT, Sullivan LA, Slavich P, 'Sea-level rise impacts on coastal water quality: Interactions between porewater, surface- and shallow groundwater geochemistry', National Convention Centre, Canberra (2010)
2009 Chalmers AC, Erskine WD, Keene A, Bush R, 'Flow regimes influencing riparian vegetation on an unregulated sand-bed stream in the Hunter Valley, NSW', H2009: Proceedings of H2009, the 32nd Hydrology and Water Resources Symposium, Newcastle, NSW (2009) [E1]
Co-authors Anita Chalmers
2009 Keene A, Erskine WD, Chalmers AC, Bush R, Cheetham M, 'Riparian revegetation and creation of a pool-riffle sequence by river restoration works on the sand-bedded Widden Brook, Australia', The 7th International Symposium on Ecohydraulics: The International Conference of Science and Information Technologies for Sustainable Management of Aquatic Ecosystems CD-ROM, Concepcion, Chile (2009) [E1]
Co-authors Anita Chalmers
2009 Burton ED, Johnston SG, Bush RT, Sullivan LA, Keene AF, Watling K, 'Iron-sulfur biomineralisation and arsenic mobility in acid-sulfate wetlands', Awards Ceremony Speeches and Abstracts of the 19th Annual V.M. Goldschmidt Conference, Davos Switzerland (2009)
2009 Bush RT, 'Top down and bottom up: The formation of river terraces through longitudinal interaction', Melbourne Australia (2009)
2009 Erskine WD, Keene AF, Bush RT, Cheetham MD, 'Biogeomorphic processes of channel contraction since the 1950¿s & 1960¿s on the sand-bedded, Widden Brook, Australia', Melbourne Australia (2009)
2008 Keene AF, Bush RT, Cheetham MD, Erskine WD, 'Reformation of pool-riffle sequences and induced bed amouring in a sand-bed stream following river rehabilitation', Sediment Dynamics in Changing Environments, Christchurch, NZ (2008) [E1]
Citations Scopus - 1
2008 Cheetham MD, Keene AF, Erskine WD, Bush RT, Jacobsen G, 'Connecting the disconnected: Longitudinal correlation of river terrace remnants', Sediment Dynamics in Changing Environments, Christchurch, NZ (2008) [E1]
Citations Scopus - 3
2008 Burton ED, Bush RT, Sullivan LA, Hocking RK, Mitchell DRG, 'Unravelling the oxidative geochemistry of monosulfidic black ooze', Guangzhou China (2008)
2008 Bush RT, 'Formation of pool-riffle sequences in a sandbed stream of the upper Hunter', Queenstown Australia (2008)
2008 Bush RT, Burton ED, Sullivan LA, Johnston SJ, 'Catatlytic action of aqueous ferrous iron and sulfide on the transformation of iron oxides in acid sulfate soils', Guangzhou China (2008)
2008 Cheetham MD, Keene AF, Bush RT, Erskine WD, 'River terrace sequences in the Widden Valley: relationships and processes', Queenstown (2008)
Show 20 more conferences

Patent (1 outputs)

Year Citation Altmetrics Link
2000 Sullivan LA, Bush RT, McConchie DM, Apparatus for analyzing reduced inorganic sulfur (2000)

Report (37 outputs)

Year Citation Altmetrics Link
2014 Ward NJ, Bush RT, Wang Z, Sullivan LA, Fyfe DM, Choppola G, et al., 'Investigations into the factors affecting the rates of recovery of acid sulfate soils in the Lower Lakes', South Australian Department of Environment, Water and Natural Resources (2014)
2013 Ward NJ, Sullivan LA, Bush RT, 'Lower Lakes acid sulfate soil detailed conceptual models', South Australian Department of Environment, Water and Natural Resources (2013)
2013 Sullivan LA, Ward NJ, Bush RT, Hidden A, Fyfe DM, Bush M, Maher CA, 'Lower Lakes carbon project: the aquatic vegetation contribution to carbon pools', South Australian Department of Environment, Water and Natural Resources (2013)
2013 Sullivan LA, Ward NJ, Rosicky MA, Li S, Bush RT, Fyfe DM, et al., 'Recovery of acid sulfate sediments in the Lower Lakes', South Australian Department of Environment, Water and Natural Resources (2013)
2012 Sullivan LA, Ward NJ, Bush RT, Cheetham MD, Cheeseman PJ, Fyfe DM, et al., 'Lower Lakes Phase 1 sulfate reduction monitoring project', South Australian Department of Environment, Water and Natural Resources (2012)
2012 Sullivan LA, Ward NJ, Parr JF, Bush RT, Fyfe DM, Bush M, et al., 'Lower Lakes Phase 1 sulfate reduction monitoring project', South Australian Department of Environment, Water and Natural Resources (2012)
2011 Ward NJ, Bush RT, Sullivan LA, Coughran J, Fyfe DM, 'Assessment of Acid Sulfate Soil Materials (Phase 2): Edward-Wakool channel system', Murray-Darling Basin Authority, 90 (2011)
2011 Ward NJ, Bush RT, Sullivan LA, Coughran J, Fyfe DM, 'Assessment of Acid Sulfate Soil Materials (Phase 2): Boeill Creek/Lagoon Wetland Complex', Murray-Darling Basin Authority (2011)
2011 Ward NJ, Bush RT, Sullivan LA, Coughran J, Fyfe DM, 'Assessment of Acid Sulfate Soil Materials (Phase 2): Glen Esk-Rusty Waterhole', Murray-Darling Basin Authority (2011)
2011 Ward NJ, Bush RT, Sullivan LA, Coughran J, Fyfe MD, 'Assessment of Acid Sulfate Soil Materials (Phase 2): Boiling Downs Creek', Murray-Darling Basin Authority, 35 (2011)
2011 Bush RT, 'Assessment of Acid Sulfate Soil Materials (Phase 2): Wakool River Billabong (Wetland ID 20246)', Murray-Darling Basin Authority, 38 (2011)
2011 Ward NJ, Bush RT, Sullivan LA, Coughran J, Fyfe DM, 'Assessment of Acid Sulfate Soil Materials (Phase 2): Brickworks Lagoon', Southern Cross University (2011)
2010 Bush RT, Tulau M, Coughran J, Ward NJ, Wong VNL, Cheetham M, Morand D, 'Distribution and hazard of sulfidic sediments in a river and creek channel system of the Murray-Darling Basin: Edward-Wakool channel system case study', Southern Cross University, 1 (2010)
2010 Sullivan LA, Fitzpatrick RW, Bush RT, Burton ED, Shand P, Ward NJ, 'The classification of acid sulfate soil materials: further modifications', Southern Cross University, 49 (2010)
2010 Bush RT, Ward NJ, Wong VNL, Cheetham J, Coughran J, 'Distribution and hazard of sulfidic sediments in a river and creek channel system of the Murray-Darling Basin: Edward-Wakool channel system case study (Preliminary Activity Statement)', Southern Cross University, 48 (2010)
2010 Sullivan LA, Burton ED, Ward NJ, Bush RT, Coughran J, Fyfe DM, et al., 'Lower Lakes sulfate reduction study (Interim report)', outh Australian Environmental Protection Authority (EPA), 1 (2010)
2010 Bush RT, Keene AF, Erskine WD, Sullivan LA, White I, Bowman G, et al., 'Restoring hydrological connectivity of surface and ground waters: Biogeochemical processes and environmental benefits for river landscapes', ARC, 102 (2010)
2010 Ward NJ, Wong VNL, Bush RT, Sullivan LA, Fyfe DM, Coughran J, McIntyre T, 'Assessment of acid sulfate soil materials in the Talwood-Mungindi region of the Murray-Darling Basin', Southern Cross University, 49 (2010)
2010 Ward NJ, Bush RT, Sullivan LA, Cheeseman P, McGrath R, Fyfe DM, et al., 'Assessment of acid sulfate soil materials in the Mildura region of the Murray-Darling Basin', Southern Cross University, 151 (2010)
2010 Ward NJ, Bush RT, Sullivan LA, Southwell M, Fyfe DM, Cheeseman PJ, et al., 'Assessment of Acid Sulfate Soil materials in RAMSAR wetlands of the Murray- Darling Basin: Fivebough and Tuckerbil Swamps', Murray-Darling Basin Authority, 38 (2010)
2010 Ward NJ, Bush RT, Sullivan LA, Coughran J, Cheeseman PJ, Fyfe DM, et al., 'Sediment and Water Quality Assessment. Rehabilitation of Moira Lake Wetland System (Stage 3)', The Public Works ¿ NSW Water Solutions, 79 (2010)
2010 Ward NJ, Bush RT, Sullivan LA, Fyfe DM, Coughran J, Tulau M, et al., 'Assessment of acid sulfate soil materials in the Edward and Wakool Rivers region of the Murray-Darling Basin', Southern Cross University, 162 (2010)
2010 Ward NJ, Bush RT, Sullivan LA, Fyfe DM, Coughran J, Tulau M, et al., 'Assessment of acid sulfate soil materials in the River Murray, Hume to Yarrawonga region of the Murray-Darling Basin', Southern Cross University, 119 (2010)
2010 Ward NJ, Bush RT, Sullivan LA, Coughran J, Fyfe DM, 'Assessment of Acid Sulfate Soil Materials (Phase 2): Fivebough and Tuckerbil Swamps', Murray-Darling Basin Authority, 66 (2010)
2010 Ward NJ, Bush RT, Clay C, Wong VNL, Sullivan LA, 'Distribution and ecological risk of reduced inorganic sulfur compounds in river and creek channels of the Murray-Darling Basin ¿ Stage One: desktop assessment', Murray-Darling Basin Authority, 116 (2010)
2009 Sullivan LA, Bush RT, Ward NJ, Fyfe DM, Johnston M, Burton ED, et al., 'Lower Lakes laboratory study of contaminant mobilisation under seawater and freshwater inundation (long-term study)', South Australian Environmental Protection Authority, 377 (2009)
2009 Bush RT, Ward NJ, Sullivan LA, Southwell M, Fyfe DM, Cheeseman P, et al., 'Assessment of Acid Sulfate Soil materials in RAMSAR wetlands of the Murray- Darling Basin: Currawinya Lakes (Currawinya National Park)', Murray-Darling Basin Authority, 41 (2009)
2009 Sullivan LA, Fitzpatrick RW, Bush RT, Burton ED, Shand P, Ward NJ, 'Modifications to the classification of acid sulfate soil material. Prepared for Murray-Darling Basin Authority', Southern Cross University, 11 (2009)
2009 Bush RT, 'Assessment of Acid Sulfate Soil materials in RAMSAR wetlands of the Murray- Darling Basin: Macquarie Marshes Nature Reserve', Murray Darling-Basin Authority, 37 (2009)
2009 Bush RT, Ward NJ, Sullivan LA, Southwell M, Fyfe DM, Cheeseman P, et al., 'Assessment of Acid Sulfate Soil materials in RAMSAR wetlands of the Murray Darling Basin: Narran Lake Nature Reserve', Murray Darling Basin Authority, 38 (2009)
2009 Ward N, Bush RT, Sullivan L, Burton E, Cheeseman P, 'Study of monosulfidic black ooze (MBO) in the Geographe Bay area, Western Australia', Department of Environment, WA, 94 (2009)
2009 Sullivan LA, Ward NJ, Bush RT, Southwell M, Fyfe DM, Cheeseman P, et al., 'Assessment of Acid Sulfate Soil materials in RAMSAR wetlands of the Murray- Darling Basin: Paroo River Wetlands', Murray-Darling Basin Authority, 38 (2009)
2009 Sullivan LA, Ward NJ, Bush RT, Southwell M, Fyfe DM, Cheeseman P, et al., 'Assessment of Acid Sulfate Soil materials in RAMSAR wetlands of the Murray- Darling Basin: NSW Central State Forest', Murray-Darling Basin Authority, 37 (2009)
2009 Sullivan LA, Ward NJ, Bush RT, Southwell M, Fyfe DM, Cheeseman P, et al., 'Assessment of Acid Sulfate Soil materials in RAMSAR wetlands of the Murray- Darling Basin: Gwydir Wetlands', Murray Darling-Basin Authority, 34 (2009)
2008 Bush RT, Burton ED, Sullivan LA, 'Assessment of Monosulfidic Black Ooze (MBO) - Thrumster Sewerage Treatment Plant Effluent Disposal to Partridge Creek', Port Macquarie-Hastings Council, 94 (2008)
2007 Johnston SG, Bush RT, Sullivan LA, Burton ED, Ahern C, Smith D, et al., 'East Trinity - Innovative acid sulfate soil management research site', Queensland Department of Natural Resources and Water, and the Cooperative Research Centre for Contamination Assessment and Remediation of the Environment, 1 (2007)
2006 Sullivan LA, Bush RT, Burton ED, 'Acid sulfate soil development issues in the Peel region', Department of Environment, Western Australia, 1 (2006)
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Grants and Funding

Summary

Number of grants 22
Total funding $5,427,536

Click on a grant title below to expand the full details for that specific grant.


20187 grants / $1,339,625

Evocra Foundation Project$421,718

Funding body: Evocra Pty Ltd

Funding body Evocra Pty Ltd
Project Team Professor Geoffrey Evans, Professor Richard Bush, Doctor Subhasish Mitra, Doctor Zhaohui Wang
Scheme Research Project
Role Investigator
Funding Start 2018
Funding Finish 2020
GNo G1800509
Type Of Funding C3111 - Aust For profit
Category 3111
UON Y

Tailings to Topsoil - Muswellbrook Shire Council Component$300,000

Funding body: Muswellbrook Shire Council

Funding body Muswellbrook Shire Council
Project Team Associate Professor Kenneth Williams, Professor Nanthi Bolan, Professor Richard Bush, Associate Professor Craig Wheeler, Doctor Peter Robinson, Doctor Raja Dharmarajan, Doctor Dusan Ilic, Doctor Jianhua Du
Scheme Research Grant
Role Investigator
Funding Start 2018
Funding Finish 2021
GNo G1801039
Type Of Funding C2210 - Aust StateTerritoryLocal - Own Purpose
Category 2210
UON Y

Tailings to Topsoil – Bengalla Mining Company Component$300,000

Funding body: Bengalla Mining Company Pty Limited

Funding body Bengalla Mining Company Pty Limited
Project Team Associate Professor Kenneth Williams, Professor Nanthi Bolan, Professor Richard Bush, Associate Professor Craig Wheeler, Doctor Peter Robinson, Doctor Raja Dharmarajan, Doctor Dusan Ilic, Doctor Jianhua Du, Dr Lukas Van Zwieten
Scheme Research Grant
Role Investigator
Funding Start 2018
Funding Finish 2021
GNo G1801042
Type Of Funding C3111 - Aust For profit
Category 3111
UON Y

Hunter Energy Transition Alliance: Research and Coordination Team$194,209

Funding body: AGL Energy

Funding body AGL Energy
Project Team Professor Richard Bush, Doctor Michael Askew, Doctor Cristelle Maurin
Scheme Research Grant
Role Lead
Funding Start 2018
Funding Finish 2018
GNo G1800194
Type Of Funding C3111 - Aust For profit
Category 3111
UON Y

Removal of micro/nanoplastics and associated contaminants from wastewater using advanced treatment technologies$49,899

Funding body: Inovin Pty Ltd

Funding body Inovin Pty Ltd
Project Team Doctor Thava Palanisami, Professor Richard Bush, Professor Geoffrey Evans, Doctor Zhaohui Wang
Scheme Entrepreneurs' Programme: Innovation Connections
Role Investigator
Funding Start 2018
Funding Finish 2018
GNo G1800601
Type Of Funding C3111 - Aust For profit
Category 3111
UON Y

Removal of micro/nanoplastics and associated contaminants from wastewater using advanced treatment technologies$49,899

Funding body: Department of Industry, Innovation and Science

Funding body Department of Industry, Innovation and Science
Project Team Doctor Thava Palanisami, Professor Richard Bush, Professor Geoffrey Evans, Doctor Zhaohui Wang
Scheme Entrepreneurs' Programme: Innovation Connections
Role Investigator
Funding Start 2018
Funding Finish 2018
GNo G1800655
Type Of Funding C2110 - Aust Commonwealth - Own Purpose
Category 2110
UON Y

Rice Crop Failure at "North Corynnia", Griffith NSW and the Potential Implication of Monosulfidic Black Ooze, water Quality and Water Management$23,900

Funding body: Thompson Cooper Lawyers

Funding body Thompson Cooper Lawyers
Project Team Professor Richard Bush
Scheme Research Grant
Role Lead
Funding Start 2018
Funding Finish 2018
GNo G1800406
Type Of Funding C3111 - Aust For profit
Category 3111
UON Y

20175 grants / $195,087

OCRA Technology Development Plan$63,750

Funding body: Evocra Pty Ltd

Funding body Evocra Pty Ltd
Project Team Professor Geoffrey Evans, Professor Richard Bush, Doctor Zhaohui Wang, Doctor Subhasish Mitra
Scheme Research Project
Role Investigator
Funding Start 2017
Funding Finish 2017
GNo G1701639
Type Of Funding C3111 - Aust For profit
Category 3111
UON Y

Energy Transition in the Hunter Region: Social dynamics, policy implications and opportunities for the energy sector$53,636

Funding body: AGL Energy

Funding body AGL Energy
Project Team Professor Richard Bush, Doctor Cristelle Maurin, Doctor Michael Askew
Scheme Research Grant
Role Lead
Funding Start 2017
Funding Finish 2017
GNo G1700760
Type Of Funding C3111 - Aust For profit
Category 3111
UON Y

UHMD Hunter River Water Quality Study$51,000

Funding body: NSW Minerals Council

Funding body NSW Minerals Council
Project Team Professor Richard Bush, Doctor Zhaohui Wang, Doctor Thava Palanisami
Scheme Research Grant
Role Lead
Funding Start 2017
Funding Finish 2017
GNo G1701095
Type Of Funding C2210 - Aust StateTerritoryLocal - Own Purpose
Category 2210
UON Y

Pumped Hydro Energy Storage Pre-Feasibility Study$26,700

Funding body: Muswellbrook Shire Council

Funding body Muswellbrook Shire Council
Project Team Professor Richard Bush, Professor Steven Weller, Doctor Michael Askew, Dr Matthew Ives
Scheme Research Grant
Role Lead
Funding Start 2017
Funding Finish 2017
GNo G1701448
Type Of Funding C2220 - Aust StateTerritoryLocal - Other
Category 2220
UON Y

Bridging Account$1

Funding body: University of Newcastle

Funding body University of Newcastle
Project Team Professor Richard Bush
Scheme Bridging Accounts
Role Lead
Funding Start 2017
Funding Finish 2017
GNo G1701193
Type Of Funding Internal
Category INTE
UON Y

20165 grants / $368,924

Assessment of self-heating test standards and their applicability for determining self-heating susceptibility within coal storage and transport systems$194,800

Funding body: Australian Coal Research Limited

Funding body Australian Coal Research Limited
Project Team Associate Professor Kenneth Williams, Associate Professor Tom Honeyands, Associate Professor Merrick Mahoney, Associate Professor Jianglong Yu, Professor Richard Bush, Doctor Peter Robinson, Mr TOBIAS Krull
Scheme Australian Coal Association Research Program (ACARP)
Role Investigator
Funding Start 2016
Funding Finish 2016
GNo G1601225
Type Of Funding Aust Competitive - Non Commonwealth
Category 1NS
UON Y

Sulfur Cycling in Toxic Oozes, Microbialites and Petroleum $68,812

Funding body: ARC (Australian Research Council)

Funding body ARC (Australian Research Council)
Project Team Professor Richard Bush, Professor Kliti Grice, Professor Pieter Visscher, Professor Alex Sessions, Professor Lorenz Schwark
Scheme Discovery Projects
Role Lead
Funding Start 2016
Funding Finish 2017
GNo G1601169
Type Of Funding Aust Competitive - Commonwealth
Category 1CS
UON Y

Pacific National Haulage Project$62,520

Funding body: Pacific National

Funding body Pacific National
Project Team Doctor Hamish Waterer, Professor Richard Bush, Doctor Thomas Kalinowski
Scheme Research Grant
Role Investigator
Funding Start 2016
Funding Finish 2016
GNo G1601141
Type Of Funding C3111 - Aust For profit
Category 3111
UON Y

Upper Hunter Mining Dialogue Perceptions Survey$24,792

Funding body: NSW Minerals Council

Funding body NSW Minerals Council
Project Team Professor Richard Bush, Doctor Brent Jenkins, Ms Ruth McLeod
Scheme Research Grant
Role Lead
Funding Start 2016
Funding Finish 2016
GNo G1601155
Type Of Funding C2210 - Aust StateTerritoryLocal - Own Purpose
Category 2210
UON Y

NSW Mine Rehabilitation$18,000

Funding body: NSW Minerals Council

Funding body NSW Minerals Council
Project Team Professor Richard Bush, Doctor Dane Lamb, Doctor Peter Sanderson
Scheme Research Grant
Role Lead
Funding Start 2016
Funding Finish 2016
GNo G1600975
Type Of Funding C3111 - Aust For profit
Category 3111
UON Y

20151 grants / $443,900

Sulfur cycling in toxic oozes, microbialites and petroleum$443,900

Funding body: ARC (Australian Research Council)

Funding body ARC (Australian Research Council)
Project Team

Grice K, Bush RT, Visscher P, Sessions A, Schwark, L

Scheme Discovery Projects
Role Investigator
Funding Start 2015
Funding Finish 2018
GNo
Type Of Funding External
Category EXTE
UON N

20141 grants / $2,000,000

Regional nuclear magnetic resonance infrastructure network for South East Queensland and Northern New South Wales$2,000,000

Funding body: ARC (Australian Research Council)

Funding body ARC (Australian Research Council)
Project Team

Quinn R, Grkovic T, Wilson J, von Itzsten M, Poulsen SA, Wellard R, MullenK, Bottle S, Zhu HY, Nelson C, Greatrex B, Fellows C, Taylor M, Keddie D, Wilson B, Cummins S, Mounsey K, Macdonald J, McMillan D, Benkendorff K, King G, Bush R, Sullivan L.

Scheme Linkage Infrastructure Equipment & Facilities (LIEF)
Role Investigator
Funding Start 2014
Funding Finish 2014
GNo
Type Of Funding External
Category EXTE
UON N

20131 grants / $150,000

Three dimensional analysis of important organic components in Energy, Environment and Earth Systems$150,000

Funding body: ARC (Australian Research Council)

Funding body ARC (Australian Research Council)
Project Team

Grice K, Charrois J, Woltering M, Blyth A, Bush RT, Sullivan LA, Murphy D, Greenwood P, Skrzypek G, Trengove R.

Scheme Linkage Infrastructure Equipment & Facilities (LIEF)
Role Investigator
Funding Start 2013
Funding Finish 2013
GNo
Type Of Funding External
Category EXTE
UON N

20121 grants / $330,000

Episodic estuarine hypoxia: resolving the geochemistry of coastal floodplain blackwaters$330,000

Funding body: ARC (Australian Research Council)

Funding body ARC (Australian Research Council)
Project Team

Sullivan LA, Burton E, Rose, A, Johnston, S., Wong, V., Bush, RT

Scheme Linkage Projects
Role Investigator
Funding Start 2012
Funding Finish 2015
GNo
Type Of Funding External
Category EXTE
UON N

20111 grants / $600,000

Electron flow in iron hyper-enriched acidifying coastal environments: reaction paths and kinetics of iron-sulfur-carbon transformations$600,000

Funding body: ARC (Australian Research Council)

Funding body ARC (Australian Research Council)
Project Team

Bush RT, Grice K, Moreau JW, Sullivan LA, Burton ED, Rose AL, Johnston SG, McElnea AE, Ahern CR

Scheme Linkage Projects
Role Lead
Funding Start 2011
Funding Finish 2014
GNo
Type Of Funding External
Category EXTE
UON N
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Research Supervision

Number of supervisions

Completed0
Current4

Current Supervision

Commenced Level of Study Research Title Program Supervisor Type
2018 Masters Developing Food Sustainability Knowledge in the Hunter Region, NSW, Accounting for a Changing Climate M Philosophy (SustainResMngt), Faculty of Science, The University of Newcastle Principal Supervisor
2018 PhD Land and the Green Economy PhD (Economics), Faculty of Business and Law, The University of Newcastle Principal Supervisor
2018 PhD Costs of Community Supported Coal Transition Policies in the Hunter Valley, New South Wales PhD (Human Geography), Faculty of Science, The University of Newcastle Principal Supervisor
2017 PhD The Degradation Process of the Phenicol Antibiotics by the Advanced Oxidation Method. PhD (Environmental Sc), Faculty of Science, The University of Newcastle Principal Supervisor
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Research Collaborations

The map is a representation of a researchers co-authorship with collaborators across the globe. The map displays the number of publications against a country, where there is at least one co-author based in that country. Data is sourced from the University of Newcastle research publication management system (NURO) and may not fully represent the authors complete body of work.

Country Count of Publications
Australia 109
China 15
Singapore 3
Korea, Republic of 2
Germany 1
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News

Reaping the benefits of agricultural waste

November 21, 2017

Revolutionary technology is being developed in partnership with the University of Newcastle that will convert agricultural waste to biofuel for the first time.

Professor Richard Bush

Position

Global Innovation Chair, International Centre for Balanced Land Use
International Centre for Balanced Land Use
School of Environmental and Life Sciences
Faculty of Science

Focus area

Earth Sciences

Contact Details

Email richard.bush@newcastle.edu.au
Phone (02) 4033 9229
Mobile 0428268587

Office

Room SR, Block, Room 281
Building NIER
Location Callaghan
University Drive
Callaghan, NSW 2308
Australia
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