2024 |
Bari ASMF, Choppala G, Lamb D, Hamilton JL, Sathish C, Rahman MM, Naidu R, Aughterson R, Burton ED, 'Is beudantite a stable host phase of arsenic and lead? New insights from molecular-scale kinetic analyses', JOURNAL OF HAZARDOUS MATERIALS, 480 (2024) [C1]
Beudantite, an As-Pb containing Fe(III) sulfate secondary mineral, is formed via the oxidation of sulfide-rich tailings in mining-impacted regions. The geochemical stability of be... [more]
Beudantite, an As-Pb containing Fe(III) sulfate secondary mineral, is formed via the oxidation of sulfide-rich tailings in mining-impacted regions. The geochemical stability of beudantite plays a key role in controlling the cycling and transport of As and Pb in mine sites. However, the fate of beudantite under dynamic pH conditions and its effect on As and Pb mobility remain elusive. We investigated the mobility dynamics of As and Pb during the dissolution of beudantite under variable pH conditions (2-8) relevant to mine sites by using a complementary suite of analytical methods. Results demonstrate that under acidic pH conditions, aqueous As and Pb content increased slightly, with just 0.7 % and 6.7 % of As and Pb partitioned from the beudantite crystal structure over 56 days. Notably, the rate at which the dissolution of beudantite led to solubilization of elements followed the order Fe > As > Pb within the first 2 h of dissolution. In contrast, the order shifted to Pb > Fe > As after 2 h. Arsenic K-edge X-ray absorption spectroscopy analyses revealed no shifts in As speciation or secondary mineralogical transformation. Here, we show for the first time that beudantite could be considered a relatively stable mineral host for As and Pb over a broad spectrum of environmental conditions. Beudantite can be expected to immobilise metals liberated by the primary weathering of sulfide-rich mine wastes, thereby lowering the risk to the environment and human health resulting from their discharge into the surrounding environment and aquifer.
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2024 |
Rastegari M, Karimian N, Johnston SG, Choppala G, Moghaddam MH, Burton ED, 'Antimony sorption to schwertmannite in acid sulfate environments', Journal of Hazardous Materials, 478 (2024) [C1]
Schwertmannite is a poorly-crystalline Fe(III) oxyhydroxysulfate mineral that may control Sb(V) mobility in acid sulfate environments, including acid mine drainage and acid sulfat... [more]
Schwertmannite is a poorly-crystalline Fe(III) oxyhydroxysulfate mineral that may control Sb(V) mobility in acid sulfate environments, including acid mine drainage and acid sulfate soils. However, the mechanisms that govern uptake of aqueous Sb(V) by schwertmannite in such environments are poorly understood. To address this issue, we examined Sb(V) sorption to schwertmannite across a range of environmentally-relevant Sb(V) loadings at pH 3 in sulfate-rich solutions. Antimony K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy revealed that Sb(V) sorption (at all loadings) involved edge and double-corner sharing linkages between SbVO6 and FeIIIO6 octahedra. The coordination numbers for these linkages indicate that sorption occurred by Sb(V) incorporation into the schwertmannite structure via heterovalent Sb(V)-for-Fe(III) substitution. As such, Sb(V) sorption to schwertmannite was not limited by the abundance of surface complexation sites and was strongly resistant to desorption when exposed to 0.1 M PO43-. Sorption of Sb(V) also conferred increased stability to schwertmannite, based on changes in the schwertmannite dissolution rate during extraction with an acidic ammonium oxalate solution. This study provides new insights into Sb(V) sorption to schwertmannite in acid sulfate environments, and highlights the role that schwertmannite can play in immobilizing Sb(V) within its crystal structure.
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2024 |
Hosseinpour Moghaddam M, Karimian N, Johnston SG, Choppala G, Rastegari M, Burton ED, 'Antimony(V) sorption and coprecipitation with ferrihydrite: An examination of retention mechanisms and the selectivity of commonly-applied extraction procedures', Journal of Hazardous Materials, 480 (2024) [C1]
We investigated the mechanisms that control Sb(V) sorption and coprecipitation with ferrihydrite across a range of Sb(V) loadings, and examined the associated effects on Sb(V) ext... [more]
We investigated the mechanisms that control Sb(V) sorption and coprecipitation with ferrihydrite across a range of Sb(V) loadings, and examined the associated effects on Sb(V) extractability during the commonly-applied 1 M HCl extraction scheme and the BCR and Wenzel sequential extraction schemes. EXAFS spectroscopy reveals that Sb(V) sorption and coprecipitation mainly involved Sb(V) incorporation into the ferrihydrite structure via edge sharing and double-corner sharing between SbO6 and FeO6 octahedra. Large amounts of these linkages partially stabilized ferrihydrite against extraction with 1 M HCl. Negligible (< 0.5 %) ferrihydrite-bound Sb(V) was recovered in the "acid extractable" and "reducible" fractions of the BCR scheme, while 1¿16 % was recovered in the "oxidizable" fraction. As such, the BCR scheme risks ferrihydrite-bound Sb(V) being misidentified as Sb residing mainly in "residual" phases. In contrast, in the Wenzel scheme, almost all sorbed- and coprecipitated-Sb(V) was recovered in the "amorphous hydrous oxide-bound" fraction, with only 0.6¿3.3 % in the "specifically-bound" fraction (consistent with our finding of Sb(V) retention via incorporation into ferrihydrite, as opposed to adsorption by the ferrihydrite surface). Collectively, the results provide new insights into the retention mechanisms and extraction behaviour of ferrihydrite-bound Sb(V), enhancing our ability to assess Sb contamination in soils, sediments and geogenic wastes.
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2024 |
Rastegari M, Karimian N, Johnston SG, Choppala G, Hosseinpour Moghaddam M, Burton ED, 'Antimony-bearing schwertmannite transformation to goethite: A driver of antimony mobilization in acid mine drainage', Journal of Hazardous Materials, 480 (2024) [C1]
Antimony(V) mobility in acid mine drainage (AMD) is often controlled by sorption and coprecipitation with schwertmannite ¿ a poorly-ordered Fe(III) oxyhydroxysulfate mineral. Howe... [more]
Antimony(V) mobility in acid mine drainage (AMD) is often controlled by sorption and coprecipitation with schwertmannite ¿ a poorly-ordered Fe(III) oxyhydroxysulfate mineral. However, due to its metastable nature, schwertmannite transforms over time to more thermodynamically stable Fe(III) phases, such as goethite. This study examines how transformation of Sb(V)-bearing schwertmannite to goethite impacts Sb(V) mobility, while also assessing the role that Sb(V) may play in stabilizing schwertmannite against such transformation. To address these aims, Sb(V)-free, Sb(V)-sorbed and Sb(V)-coprecipitated schwertmannite were allowed to undergo partial transformation to goethite under acid sulfate conditions. Iron K-edge EXAFS spectroscopy revealed that sorbed and coprecipitated Sb(V) partly stabilized schwertmannite against transformation. The onset of schwertmannite transformation to goethite was found to drive clear mobilization of Sb(V) into solution, regardless of the Sb(V) loading or whether Sb(V) was initially sorbed or coprecipitated with the precursor schwertmannite. This initial phase of Sb(V) mobilization was followed by subsequent solid-phase recapture of the released Sb(V), with Sb K-edge EXAFS spectroscopy revealing that this process involved Sb(V) incorporation into the newly-formed goethite. Our findings show that, although schwertmannite transformation to goethite is partially inhibited by co-existing Sb(V), the initial stage of this transformation process drives significant Sb(V) mobilization in AMD systems.
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2022 |
Yeasmin M, Lamb D, Choppala G, Rahman MM, 'Selenium Accumulation and Speciation in Chickpea (Cicer arietinum) Impacted by S in Soils: Potential for Biofortification', ACS AGRICULTURAL SCIENCE & TECHNOLOGY, 2, 135-143 (2022) [C1]
Dietary selenium (Se) deficiency is a well-known global problem originating from food crops grown in Se-deficient soil. Agronomic Se biofortification is one of the suitable option... [more]
Dietary selenium (Se) deficiency is a well-known global problem originating from food crops grown in Se-deficient soil. Agronomic Se biofortification is one of the suitable options to minimize Se deficiency. Sulfur (S) is chemically similar to Se, and the role of S on the uptake and transformation of Se in grain has not been resolved. Considering this, our study examines the influence of S on the speciation and accumulation of Se in two chickpea cultivars (Amber and PBA sheamer) grown in Se-deficient soil under glasshouse conditions. Two doses of S (0 and 14 mg kg-1) as sulfate and three doses of Se (0, 1, and 2 mg kg-1) as selenate (SeVI) were used in a randomized factorial design. The addition of SeVI increased the Se content in grain in both cultivars compared to the control treatment. Speciation of Se analysis in grain showed that most (85%) of the Se accumulated in chickpea grain in the organic forms of Se as SeCys and MeSeCys. At 2 mg/kg Se addition, the biomass and grain yield was significantly reduced (P < 0.01), while S addition tended to increase the yield. Inorganic Se was below 15%, primarily as SeVI. PBA Sheamer, a desi type and widely grown chickpea cultivar, showed the most significant proportion of organic Se species, SeCys (57%) and SeMeCys (40%). Application of S contemporarily with Se showed increased SeMeCys production in the grain of PBA Sheamer cultivar. These findings indicated that the accumulation and speciation of Se in chickpea grain was dependent on both Se and S fertilization.
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Open Research Newcastle |
2022 |
Choppala G, Lamb D, Aughterson R, Burton ED, 'Tooeleite Transformation and Coupled As(III) Mobilization Are Induced by Fe(II) under Anoxic, Circumneutral Conditions', ENVIRONMENTAL SCIENCE & TECHNOLOGY (2022) [C1]
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Open Research Newcastle |
2022 |
Rastegari M, Karimian N, Johnston SG, Doherty SJ, Hamilton JL, Choppala G, Moghaddam MH, Burton ED, 'Antimony(V) Incorporation into Schwertmannite: Critical Insights on Antimony Retention in Acidic Environments', ENVIRONMENTAL SCIENCE & TECHNOLOGY, 56, 17776-17784 (2022) [C1]
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Open Research Newcastle |
2022 |
Choppala G, Karimian N, Burton ED, 'An X-ray absorption spectroscopic study of the Fe(II)-induced transformation of Cr(VI)-substituted schwertmannite', JOURNAL OF HAZARDOUS MATERIALS, 431 (2022) [C1]
The environmental chemistry of Cr is of widespread interest due to the hazardous nature of Cr(VI). Because of similar atomic size and charge, CrVIO42- can substitute for SO42- wit... [more]
The environmental chemistry of Cr is of widespread interest due to the hazardous nature of Cr(VI). Because of similar atomic size and charge, CrVIO42- can substitute for SO42- within schwertmannite - an Fe(III) oxyhydroxysulfate mineral that occurs widely in acidic and sulfate-rich systems. The presence of aqueous Fe(II) can induce transformation of schwertmannite to more stable Fe(III) phases (e.g. goethite) which may potentially impact the behaviour of co-associated Cr(VI). Here, we investigate the Fe(II)-induced transformation of Cr(VI)-substituted schwertmannite as a function of pH (4-8) and the degree of Cr(VI) substitution (0.16¿13 mol% CrVIO42--for-SO42- substitution). Iron K-edge EXAFS spectroscopy revealed that higher levels of Cr(VI) substitution inhibited Fe(II)-induced schwertmannite transformation. Chromium K-edge XANES spectroscopy indicated that this outcome could be partly attributed to consumption of Fe(II) by reaction with Cr(VI), and the resulting formation of a passivating Cr(III)-Fe(III) hydroxide phase which stabilizes schwertmannite at greater levels of Cr(VI) substitution and at higher pH while also decreasing further reduction of structural Cr(VI). Overall, this study enriches our understanding of interactions between hazardous Cr(VI) and schwertmannite in environmental and engineered systems.
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Open Research Newcastle |
2022 |
Yeasmin M, Lamb D, Choppala G, Rahman MM, 'Impact of Sulfur on Biofortification and Speciation of Selenium in Wheat Grain Grown in Selenium-Deficient Soils', JOURNAL OF SOIL SCIENCE AND PLANT NUTRITION, 22, 3243-3253 (2022) [C1]
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Open Research Newcastle |
2022 |
Abbasi S, Lamb DT, Choppala G, Burton ED, Megharaj M, 'Antimony speciation, phytochelatin stimulation and toxicity in plants', ENVIRONMENTAL POLLUTION, 305 (2022) [C1]
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Open Research Newcastle |
2021 |
Hoang SA, Lamb D, Seshadri B, Sarkar B, Choppala G, Kirkham MB, Bolan NS, 'Rhizoremediation as a green technology for the remediation of petroleum hydrocarbon-contaminated soils', Journal of Hazardous Materials, 401 (2021) [C1]
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Open Research Newcastle |
2021 |
Bari ASMF, Lamb D, Choppala G, Seshadri B, Islam MR, Sanderson P, Rahman MM, 'Arsenic bioaccessibility and fractionation in abandoned mine soils from selected sites in New South Wales, Australia and human health risk assessment', ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY, 223 (2021) [C1]
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Open Research Newcastle |
2021 |
Gerdelidani AF, Towfighi H, Shahbazi K, Lamb DT, Choppala G, Abbasi S, Bari ASMF, Naidu R, Rahman MM, 'Arsenic geochemistry and mineralogy as a function of particle-size in naturally arsenic-enriched soils', Journal of Hazardous Materials, 403 (2021) [C1]
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Open Research Newcastle |
2021 |
Lamb D, Choppala G, Yeasmin M, Abbasi S, Wang L, Naidu R, Reichman S, McGrath S, 'Are root elongation assays suitable for establishing metallic anion ecotoxicity thresholds?', Journal of Hazardous Materials Letters, 2 (2021) [C1]
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Open Research Newcastle |
2021 |
Burton ED, Karimian N, Johnston SG, Schoepfer VA, Choppala G, Lamb D, 'Arsenic-Imposed Effects on Schwertmannite and Jarosite Formation in Acid Mine Drainage and Coupled Impacts on Arsenic Mobility', ACS EARTH AND SPACE CHEMISTRY, 5, 1418-1435 (2021) [C1]
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Open Research Newcastle |
2021 |
Lamb D, Choppala G, Yeasmin M, Abbasi S, Wang L, Naidu R, et al., 'Are root elongation assays suitable for establishing metallic anion ecotoxicity thresholds?', Journal of Hazardous Materials Letters, 2 100024-100024 (2021)
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2020 |
Fazle Bari ASM, Lamb D, Choppala G, Bolan N, Seshadri B, Rahman MA, Rahman MM, 'Geochemical fractionation and mineralogy of metal(loid)s in abandoned mine soils: Insights into arsenic behaviour and implications to remediation', Journal of Hazardous Materials, 399 (2020) [C1]
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Open Research Newcastle |
2019 |
Burton ED, Choppala G, Vithana CL, Karimian N, Hockmann K, Johnston SG, 'Chromium(VI) formation via heating of Cr(III)-Fe(III)-(oxy)hydroxides: A pathway for fire-induced soil pollution', CHEMOSPHERE, 222, 440-444 (2019) [C1]
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2019 |
Burton ED, Choppala G, Karimian N, Johnston SG, 'A new pathway for hexavalent chromium formation in soil: Fire-induced alteration of iron oxides', ENVIRONMENTAL POLLUTION, 247, 618-625 (2019) [C1]
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2019 |
Shilpi S, Lamb D, Bolan N, Seshadri B, Choppala G, Naidu R, 'Waste to watt: Anaerobic digestion of wastewater irrigated biomass for energy and fertiliser production', Journal of Environmental Management, 239, 73-83 (2019) [C1]
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Open Research Newcastle |
2019 |
Karimian N, Burton ED, Johnston SG, Hockmann K, Choppala G, 'Humic acid impacts antimony partitioning and speciation during iron(II)-induced ferrihydrite transformation', Science of The Total Environment, 683, 399-410 (2019) [C1]
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2018 |
Choppala G, Kunhikrishnan A, Seshadri B, Park J, Bush R, Bolan N, 'Comparative sorption of chromium species as influenced by amendments in contaminated soils', Journal of Geochemical Exploration (2018) [C1]
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Open Research Newcastle |
2018 |
Bibi I, Niazi NK, Choppala G, Burton ED, 'Chromium(VI) removal by siderite (FeCO3) in anoxic aqueous solutions: An X-ray absorption spectroscopy investigation', SCIENCE OF THE TOTAL ENVIRONMENT, 640, 1424-1431 (2018) [C1]
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2018 |
Tripathi N, Choppala G, Singh RS, Hills CD, 'Impact of modified chitosan on pore water bioavailability of zinc in contaminated soils', JOURNAL OF GEOCHEMICAL EXPLORATION, 186, 94-99 (2018) [C1]
The present work examines the utilisation potential of the bio-waste, chitosan for the remediation of soils contaminated with zinc (Zn). The mechanism involved was elucidated via ... [more]
The present work examines the utilisation potential of the bio-waste, chitosan for the remediation of soils contaminated with zinc (Zn). The mechanism involved was elucidated via a study of Zn sorption kinetics on pure and modified chitosan beads, the latter containing molybdate and phosphate compounds. The effect of equilibration time on adsorption was explained with reference to chemical sorption and intra-particle diffusion mechanisms. The findings showed that chitosan acts upon freely dissolved zinc in soil pore water. The use of modified chitosan beads resulted in a significant decrease in Zn bioavailability, which may be attributed to a combination of Zn complexation, the sorbent's high surface area and cation exchange capacity (CEC). This study provides an insight into issues associated with zinc contaminated soils and the amelioration of nutrient-deficient soil through modified chitosan amendments. Capsule abstract Modified chitosan has potential to remediate Zn-contaminated soil. The bioavailability of zinc in the pore water of contaminated soils decreased upon the application of chitosan beads.
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2018 |
Choppala G, Burton ED, 'Chromium(III) substitution inhibits the Fe(II)-accelerated transformation of schwertmannite', PLOS ONE, 13 (2018) [C1]
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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]
The increased use of estuarine waters for commercial and recreational activities is one consequence of urbanisation. Western Australia's Peel-Harvey Estuary highlights the im... [more]
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.
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Open Research Newcastle |
2018 |
Qi F, Lamb D, Naidu R, Bolan NS, Yan Y, Ok YS, Rahman MM, Choppala G, 'Cadmium solubility and bioavailability in soils amended with acidic and neutral biochar', SCIENCE OF THE TOTAL ENVIRONMENT, 610, 1457-1466 (2018) [C1]
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Open Research Newcastle |
2017 |
Tripathi N, Choppala G, Singh RS, 'Evaluation of modified chitosan for remediation of zinc contaminated soils', JOURNAL OF GEOCHEMICAL EXPLORATION, 182, 180-184 (2017) [C1]
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2017 |
Qi F, Naidu R, Bolan NS, Dong Z, Yan Y, Lamb D, et al., 'Pyrogenic carbon in Australian soils', SCIENCE OF THE TOTAL ENVIRONMENT, 586 849-857 (2017) [C1]
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Open Research Newcastle |
2017 |
Seshadri B, Bolan NS, Choppala G, Kunhikrishnan A, Sanderson P, Wang H, Currie LD, Tsang DCW, Ok YS, Kim G, 'Potential value of phosphate compounds in enhancing immobilization and reducing bioavailability of mixed heavy metal contaminants in shooting range soil', CHEMOSPHERE, 184, 197-206 (2017) [C1]
Shooting range soils contain mixed heavy metal contaminants including lead (Pb), cadmium (Cd), and zinc (Zn). Phosphate (P) compounds have been used to immobilize these metals, pa... [more]
Shooting range soils contain mixed heavy metal contaminants including lead (Pb), cadmium (Cd), and zinc (Zn). Phosphate (P) compounds have been used to immobilize these metals, particularly Pb, thereby reducing their bioavailability. However, research on immobilization of Pb's co-contaminants showed the relative importance of soluble and insoluble P compounds, which is critical in evaluating the overall success of in situ stabilization practice in the sustainable remediation of mixed heavy metal contaminated soils. Soluble synthetic P fertilizer (diammonium phosphate; DAP) and reactive (Sechura; SPR) and unreactive (Christmas Island; CPR) natural phosphate rocks (PR) were tested for Cd, Pb and Zn immobilization and later their mobility and bioavailability in a shooting range soil. The addition of P compounds resulted in the immobilization of Cd, Pb and Zn by 1.56¿76.2%, 3.21¿83.56%, and 2.31¿74.6%, respectively. The reactive SPR significantly reduced Cd, Pb and Zn leaching while soluble DAP increased their leachate concentrations. The SPR reduced the bioaccumulation of Cd, Pb and Zn in earthworms by 7.13¿23.4% and 14.3¿54.6% in comparison with earthworms in the DAP and control treatment, respectively. Bioaccessible Cd, Pb and Zn concentrations as determined using a simplified bioaccessibility extraction test showed higher long-term stability of P-immobilized Pb and Zn than Cd. The differential effect of P-induced immobilization between P compounds and metals is due to the variation in the solubility characteristics of P compounds and nature of metal phosphate compounds formed. Therefore, Pb and Zn immobilization by P compounds is an effective long-term remediation strategy for mixed heavy metal contaminated soils.
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Open Research Newcastle |
2017 |
Kunhikrishnan A, Choppala G, Seshadri B, Wijesekara H, Bolan NS, Mbene K, Kim W-I, 'Impact of wastewater derived dissolved organic carbon on reduction, mobility, and bioavailability of As(V) and Cr(VI) in contaminated soils', JOURNAL OF ENVIRONMENTAL MANAGEMENT, 186, 183-191 (2017) [C1]
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Open Research Newcastle |
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]
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Open Research Newcastle |
2017 |
Bolan S, Kunhikrishnan A, Seshadri B, Choppala G, Naidu R, Bolan NS, Ok YS, Zhang M, Li C-G, Li F, Noller B, Kirkham MB, 'Sources, distribution, bioavailability, toxicity, and risk assessment of heavy metal(loid)s in complementary medicines', ENVIRONMENT INTERNATIONAL, 108, 103-118 (2017) [C1]
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Open Research Newcastle |
2016 |
Lamb DT, Kader M, Wang L, Choppala G, Rahman MM, Megharaj M, Naidu R, 'Pore-Water Carbonate and Phosphate As Predictors of Arsenate Toxicity in Soil', ENVIRONMENTAL SCIENCE & TECHNOLOGY, 50, 13062-13069 (2016) [C1]
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Open Research Newcastle |
2016 |
Mandal S, Sarkar B, Bolan N, Novak J, Ok YS, Van Zwieten L, Singh BP, Kirkham MB, Choppala G, Spokas K, Naidu R, 'Designing advanced biochar products for maximizing greenhouse gas mitigation potential', CRITICAL REVIEWS IN ENVIRONMENTAL SCIENCE AND TECHNOLOGY, 46, 1367-1401 (2016) [C1]
Greenhouse gas (GHG) emissions from agricultural operations continue to increase. Carbon (C)-enriched char materials like biochar have been described as a mitigation strategy. Uti... [more]
Greenhouse gas (GHG) emissions from agricultural operations continue to increase. Carbon (C)-enriched char materials like biochar have been described as a mitigation strategy. Utilization of biochar material as a soil amendment has been demonstrated to provide potentially greater soil GHG suppression due to its interactions in the soil system. However, these effects are variable and the duration of the impact remains uncertain. Various (nano)materials can be used to modify chars to obtain surface functionality to mitigate GHG emissions. This review critically focusses on the innovative methodologies for improving char efficiency, underpinning GHG mitigation and C sequestration.
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Open Research Newcastle |
2016 |
Choppala RA, 'Differential effect of biochar upon reduction-induced mobility and bioavailability of arsenate and chromate', Chemosphere, 144, 374-381 (2016) [C1]
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 bi... [more]
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.
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Open Research Newcastle |
2016 |
Tripathi N, Choppala G, Singh RS, Srivastava P, Seshadri B, 'Sorption kinetics of zinc and nickel on modified chitosan', ENVIRONMENTAL MONITORING AND ASSESSMENT, 188 (2016) [C1]
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Open Research Newcastle |
2015 |
Choppala G, Bolan N, Kunhikrishnan A, Skinner W, Seshadri B, 'Concomitant reduction and immobilization of chromium in relation to its bioavailability in soils', Environmental Science and Pollution Research, 22, 8969-8978 (2015) [C1]
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2014 |
Lamb DT, Venkatraman K, Bolan N, Ashwath N, Choppala G, Naidu R, 'Phytocapping: An alternative technology for the sustainable management of landfill sites', Critical Reviews in Environmental Science and Technology, 44 561-637 (2014) [C1]
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2014 |
Seshadri B, Bolan NS, Kunhikrishnan A, Choppala G, Naidu R, 'Effect of coal combustion products in reducing soluble phosphorus in soil II: Leaching study', Water, Air, and Soil Pollution, 225 (2014) [C1]
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2014 |
Choppala G, Saifullah , Bolan N, Bibi S, Iqbal M, Rengel Z, Kunhikrishnan A, Ashwath N, Ok YS, 'Cellular Mechanisms in Higher Plants Governing Tolerance to Cadmium Toxicity', Critical Reviews in Plant Sciences, 33, 374-391 (2014) [C1]
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2013 |
Choppala G, Bolan N, Lamb D, Kunhikrishnan A, 'Comparative sorption and mobility of Cr(III) and Cr(VI) species in a range of soils: Implications to bioavailability topical collection on remediation of site contamination', Water, Air, and Soil Pollution, 224 (2013) [C1]
The sorption of chromium (Cr) species to soil has become the focus of research as it dictates the bioavailability and also the magnitude of toxicity of Cr. The sorption of two env... [more]
The sorption of chromium (Cr) species to soil has become the focus of research as it dictates the bioavailability and also the magnitude of toxicity of Cr. The sorption of two environmentally important Cr species [Cr(III) and Cr(VI)] was examined using batch sorption, and the data were fitted to Langmuir and Freundlich adsorption isotherms. The effects of soil properties such as pH, CEC, organic matter (OM), clay, water-extractable SO42- and PO43-, surface charge, and different iron (Fe) fractions of 12 different Australian representative soils on the sorption, and mobility of Cr(III) and Cr(VI) were examined. The amount of sorption as shown by K f was higher for Cr(III) than Cr(VI) in all tested soils. Further, the amount of Cr(III) sorbed increased with an increase in pH, CEC, clay, and OM of soils. Conversely, the chemical properties of soil such as positive charge and Fe (crystalline) had a noticeable influence on the sorption of Cr(VI). Desorption of Cr(VI) occurred rapidly and was greater than desorption of Cr(III) in soils. The mobility of Cr species as estimated by the retardation factor was higher for Cr(VI) than for Cr(III) in all tested soils. These results concurred with the results from leaching experiments which showed higher leaching of Cr(VI) than Cr(III) in both acidic and alkaline soils indicating the higher mobility of Cr(VI) in a wide range of soils. This study demonstrated that Cr(VI) is more mobile and will be bioavailable in soils regardless of soil properties and if not remediated may eventually pose a severe threat to biota. © 2013 Springer Science+Business Media Dordrecht.
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2013 |
Bolan N, Mahimairaja S, Kunhikrishnan A, Choppala G, 'Phosphorus-arsenic interactions in variable-charge soils in relation to arsenic mobility and bioavailability', Science of the Total Environment, 463-464, 1154-1162 (2013) [C1]
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2013 |
Bolan NS, Choppala G, Kunhikrishnan A, Park J, Naidu R, 'Microbial Transformation of Trace Elements in Soils in Relation to Bioavailability and Remediation', REVIEWS OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY, VOL 225, 225, 1-56 (2013)
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2013 |
Seshadri B, Bolan N, Choppala G, Naidu R, 'Differential effect of coal combustion products on the bioavailability of phosphorus between inorganic and organic nutrient sources', Journal of Hazardous Materials, 261, 817-825 (2013) [C1]
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2013 |
Choppala G, Bolan N, Seshadri B, 'Chemodynamics of chromium reduction in soils: Implications to bioavailability', Journal of Hazardous Materials, 261, 718-724 (2013) [C1]
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2013 |
Park JH, Choppala G, Lee SJ, Bolan N, Chung JW, Edraki M, 'Comparative sorption of Pb and Cd by biochars and its implication for metal immobilization in soils', Water, Air, and Soil Pollution, 224 1-12 (2013)
Biochar has great potential as a soil amendment to immobilize heavymetals, thereby reducing their bioavailability. In this study, biochars derived from chicken manure and green wa... [more]
Biochar has great potential as a soil amendment to immobilize heavymetals, thereby reducing their bioavailability. In this study, biochars derived from chicken manure and green waste were compared with commercial activated carbon (AC) and laboratory produced black carbon (BC) for the sorption of Pb and Cd. Sorption kinetics and equilibrium sorption isotherms for Pb and Cd were obtained for the char materials and the data were fitted to kinetic and sorption isotherm models.. Chicken manure-derived biochar (CM) showed the highest sorption capacity for both Pb and Cd, and the Pb sorption by biochars was higher than the Cd sorption because of the precipitation of Pb with various ions released from the biochars such as carbonate, phosphate, and sulfate. The sorption data for both Pb and Cd were better represented by the pseudo-second order kinetic model than the pseudo-first order kinetic model, which indicates chemical sorption between biochar and metals. For the isotherm studies, char materials was mixed with various amount of Pb or Cd solutions and the remaining metal concentration was measured. The equilibrium sorption data followed a Langmuir isotherm with a maximum sorption capacity of 6.8-11 and 1.7-8.0 mg/g by biochars for Pb and Cd, respectively. Furthermore, CM immobilized Pb and Cd up to 93.5 and 88.4 %, respectively, while BC was not effective in the immobilization of Pb in soil. Overall, the sorption experiments in solution and the immobilization experiment in soil showed that biochars are more effective than AC in the sorption of Pb and Cd, and that they have the potential to be used as a soil amendment to remediate metal-contaminated soil. © Springer Science+Business Media Dordrecht 2013.
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2013 |
Park JH, Choppala G, Lee SJ, Bolan N, Chung JW, Edraki M, 'Comparative sorption of Pb and Cd by biochars and its implication for metal immobilization in soils topical collection on remediation of site contamination', Water, Air, and Soil Pollution, 224 (2013) [C1]
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2013 |
Panneerselvam P, Choppala G, Kunhikrishnan A, Bolan N, 'Potential of novel bacterial consortium for the remediation of chromium contamination', Water, Air, and Soil Pollution, 224 (2013) [C1]
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2012 |
Bolan NS, Kunhikrishnan A, Choppala GK, Thangarajan R, Chung JW, 'Stabilization of carbon in composts and biochars in relation to carbon sequestration and soil fertility', Science of the Total Environment, 424, 264-270 (2012) [C1]
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2012 |
Choppala GK, Bolan NS, Megharaj M, Chen Z, Naidu R, 'The Infl uence of Biochar and Black Carbon on Reduction and Bioavailability of Chromate in Soils', Journal of Environmental Quality, 41, 1175-1184 (2012) [C1]
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2011 |
Park JH, Choppala GK, Bolan NS, Chung JW, Chuasavathi T, 'Biochar reduces the bioavailability and phytotoxicity of heavy metals', Plant and Soil, 348, 439-451 (2011) [C1]
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2011 |
Park JH, Lamb D, Paneerselvam P, Choppala G, Bolan N, Chung JW, 'Role of organic amendments on enhanced bioremediation of heavy metal(loid) contaminated soils', Journal of Hazardous Materials, 185, 549-574 (2011) [C1]
As land application becomes one of the important waste utilization and disposal practices, soil is increasingly being seen as a major source of metal(loid)s reaching food chain, m... [more]
As land application becomes one of the important waste utilization and disposal practices, soil is increasingly being seen as a major source of metal(loid)s reaching food chain, mainly through plant uptake and animal transfer. With greater public awareness of the implications of contaminated soils on human and animal health there has been increasing interest in developing technologies to remediate contaminated sites. Bioremediation is a natural process which relies on soil microorganisms and higher plants to alter metal(loid) bioavailability and can be enhanced by addition of organic amendments to soils. Large quantities of organic amendments, such as manure compost, biosolid and municipal solid wastes are used as a source of nutrients and also as a conditioner to improve the physical properties and fertility of soils. These organic amendments that are low in metal(loid)s can be used as a sink for reducing the bioavailability of metal(loid)s in contaminated soils and sediments through their effect on the adsorption, complexation, reduction and volatilization of metal(loid)s. This review examines the mechanisms for the enhanced bioremediation of metal(loid)s by organic amendments and discusses the practical implications in relation to sequestration and bioavailability of metal(loid)s in soils. © 2010 Elsevier B.V.
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