Dr Dane Lamb

The Australian beef cattle industry is one of the most efficient and ranks third largest in beef export in the world, contributing 4% of beef supply. As on 2013, the meat value produced from beef cattle, in Australia is estimated to be $12.3 billion (Fastfacts, 2013). Beef cattle production ranges from intensive farms on fertile lands to extensive range lands. With the increase in human population and increase in affordability of meat-based food, the demand for beef cattle is also increasing

¿Mining¿ refers to the excavation of economically important resources from terrestrial landmasses, thereby generating a large quantity of valuable precursors for commercial and industrial activities. Mineral products such as coal, aluminum, copper, iron, gold, and mineral sand are examples from the mining industry. Though mining advances global economic prosperity, this industry severely disturbs the land, water resources, and the environment (Figure 4.1). Mined waste materials such as tailings, subsoils, oxidized wastes, and fireclay are the main causes for land disturbance. Presence of potentially hazardous substances such as heavy metals in elevated concentrations in the mined waste materials has caused land contamination. Poor soil characteristics such as low-level organic matter and poor soil texture and structure have resulted in deterioration of the land, adversely affecting the establishment of plants and soil microbial flora and fauna (Boyer et al. 2011, Johnson 2003, Larney and Angers 2012, Sopper 1992). Disturbed mine sites are known to contaminate water resources 60 61in many countries, mainly from acid mine drainage (Bolan et al. 2003, Lindsay et al. 2015, Taylor et al. 1997). Therefore, these sites need to be rehabilitated to minimize potential environmental consequences, thereby enhancing their utilization. Revegetation of mine sites is one of the potential strategies that can be applied to improve these disturbed land masses. Here, infertile soil properties are improved by a series of processes such as land application of biowastes

Soils are a prime and very important natural resource, and soil fertility is a major concern for sustainable agriculture and economic development of any country. In recent decades, problems of contaminated land sites, water bodies, groundwater, and air worldwide have increased manyfold due to anthropogenic activities. Mining is one of the anthropogenic activities that cause pollution problems in, around, and outside of mining areas. It results in the mobilization of metals and organic and inorganic substances into the environment, which causes pollution of air, soils, sediments, vegetation, and surface and groundwater. It also increases the morbidity and mortality of plant and animal species and results in the loss of visual, aesthetic characteristics of landscapes (Bolan et al. 2003; Pavli et al. 2015)

Degradation of land resources as a result of mining activities poses serious threat to the environment. It has been estimated that around 0.4 × 10 km area of land is impacted by mining activities around the world (Hooke and Martín-Duque 2012). Unfortunately, a significant percentage of this area has never been reclaimed, which poses health risks to ecosystems and humans. Often, these wastes contain hazardous substances such as heavy metals, organic contaminants, radionuclides, and crushed limestone, where the latter could become a potential source of atmospheric CO emission. Thus, they not only pose serious risk to the groundwater and surface water, but also to the atmosphere (Wijesekara et al. 2016). In order to tackle the issues related to mine wastes and manage the affected sites sustainably, an appropriate physical, chemical, and biological characterization of waste materials becomes very prudent. Due to the lack of both above- and below-ground biodiversity, mine waste sites are very poor in organic matter content. This in return leads to poor seed germination, plant growth, and vegetation establishment. In many cases, the associated toxic contaminants also seriously compromise the soil health, microbial life, and plant growth (Castillejo and Castelló 2010, Larney and Angers 2012). This chapter describes the physicochemical characteristics of mine wastes, including spoil, tailings, and overburden, by underpinning their source-property relationships. The value of readily available biowaste resources, including biosolids, composts, and manures, in improving such physicochemical properties of mining-impacted soils/sites is also discussed 6 2 2

Historically, mining of metalliferous ore bodies was a relatively dispersed activity, with numerous small mines occurring throughout many western countries including the United States, the United Kingdom, and Australia (Soucek et al. 2000, Grant et al. 2002, Mayes et al. 2009). Many metalliferous mine sites began operation in the late eighteenth and early nineteenth centuries and were abandoned in most instances before the environmental movement in Western countries. As such, there was very little recognition of the potential impacts caused by the dispersal of metal toxicants such as arsenic (As), cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn) into the surrounding environments from these sites. Many of these contaminants are cariogenic in humans (e.g., As), cause a range of human health-related impacts (Pb, Cd), and are toxic to ecological receptors in nearby streams and surrounding terrestrial environments (Cu, Zn, Mn, Ni). As a result of the lack of regard for potential impacts, much of the mining waste was discarded carelessly throughout mining sites, and in some cases, directly into nearby watercourses

In the era of global competition, mineral exploitation has been significantly increased resulting in pressure on the environment in the form of massive deforestation, soil pollution, and erosion. Despite global economic importance, mineral industries have adversely affected the ecosystems across the world. The impact of mine waste in soil depends on its type and composition, commodity being mined, type of ore, and technologies used to process the ore. Mining types and activities are several, which include surface mining, underground mining, openpit mining, in situ mining, pillar mining, slope mining, block caving, and quarrying. And thus mine waste materials vary in their physical and chemical composition and potential for soil contamination. The different 96types of mine waste materials are overburden, waste rock, tailings, slags, mine water, sludge, and gaseous wastes. Overburden includes the soil and rock that are removed to gain access to the ore deposits at openpit mines. It is usually dumped on the surface at mine sites where it will not hinder further expansion of the mining operation. Waste rock contains minerals in concentrations considered too low to be extracted at a profit. It is often stored in heaps on the mine site. Tailings are finely ground rock and mineral waste products of mineral processing operations. They also contain leftover processing chemicals, and usually are deposited in the form of water-based slurry into tailings ponds. Slags are nonmetallic by-products from metal smelting. Mine water is produced in a number of ways at mine sites and varies in its quality and potential for environmental contamination. Sludge is produced at active water treatment plants used at some mine sites and consists of the solids that have been removed from the water as well as any chemicals. Gaseous wastes are produced during high-temperature chemical processing such as smelting, and consist of particulate matter and oxides of sulfur

The ageing of a contaminant in soil influences the bioavailability and toxicity of environmental pollutants. Yet, despite arsenic (As) being an important terrestrial contaminant, the effect of As ageing on phytotoxicity has received relatively little research. Research to date has reported predominantly short term (< 0.5 years) experiments. Here, we studied the influence of ageing over 0.25 and 5 years on the phytotoxicity of As (as arsenate) on Cucumis sativus L. (cucumber). The study showed that increasing ageing time of As from 0.25 to 5 years increased the EC and EC values by 4.0 and 1.76 fold, respectively. The dependence of ageing on soil properties was also examined, although only Freundlich sorption parameters were correlated to the ageing factor (r = 0.68, P = 0.028). Soils with high adsorption capacity also showed the greatest change in toxicity over 5 years. In addition, data was compiled from relevant literature to develop a model for As ecotoxicity. The combined model (n = 54) showed no relationship with pH but was correlated to the oxalate extractable iron content and %clay. Arsenate ecotoxicity (EC , mg/kg) in the multivariate model was related to oxalate iron content, %clay and ageing time. Thus, the results of this study have significant implications for risk assessment of long-term As contaminated soils. 10 50 50

The term ¿Total petroleum hydrocarbons¿ (TPH) is used to describe a complex mixture of petroleum-based hydrocarbons primarily derived from crude oil. Those compounds are considered as persistent organic pollutants in the terrestrial environment. A wide array of organic amendments is increasingly used for the remediation of TPH-contaminated soils. Organic amendments not only supply a source of carbon and nutrients but also add exogenous beneficial microorganisms to enhance the TPH degradation rate, thereby improving the soil health. Two fundamental approaches can be contemplated within the context of remediation of TPH-contaminated soils using organic amendments: (i) enhanced TPH sorption to the exogenous organic matter (immobilization) as it reduces the bioavailability of the contaminants, and (ii) increasing the solubility of the contaminants by supplying desorbing agents (mobilization) for enhancing the subsequent biodegradation. Net immobilization and mobilization of TPH have both been observed following the application of organic amendments to contaminated soils. This review examines the mechanisms for the enhanced remediation of TPH-contaminated soils by organic amendments and discusses the influencing factors in relation to sequestration, bioavailability, and subsequent biodegradation of TPH in soils. The uncertainty of mechanisms for various organic amendments in TPH remediation processes remains a critical area of future research.

The influence of soil properties on PFOS sorption are not fully understood, particularly for variable charge soils. PFOS batch sorption isotherms were conducted for 114 temperate and tropical soils from Australia and Fiji, that were well-characterized for their soil properties, including total organic carbon (TOC), anion exchange capacity, and surface charge. In most soils, PFOS sorption isotherms were nonlinear. PFOS sorption distribution coefficients (Kd) ranged from 5 to 229 mL/g (median: 28 mL/g), with 63% of the Fijian soils and 35% of the Australian soils showing Kd values that exceeded the observed median Kd. Multiple linear regression showed that TOC, amorphous aluminum and iron oxides contents, anion exchange capacity, pH, and silt content, jointly explained about 53% of the variance in PFOS Kd in soils. Variable charge soils with net positive surface charges, and moderate to elevated TOC content, generally displayed enhanced PFOS sorption than in temperate or tropical soils with TOC as the only sorbent phase, especially at acidic pH ranges. For the first time, two artificial neural networks were developed to predict the measured PFOS Kd (R2 = 0.80) in the soils. Overall, both TOC and surface charge characteristics of soils are important for describing PFOS sorption.

This study investigates the effect of contaminant zinc (Zn) on lead (Pb) bioavailability and bioaccessibility in six contrasting soils spiked with 1500 mg Pb/kg and aged 12 months under laboratory conditions. Zn was added to the soils (7500 mgZn/kg soil) and aged for a further two weeks. In vivo studies were conducted using juvenile swine as a surrogate model for young children. Two compartment pharmacokinetic models were used to analyze the biological response produced by Pb oral solution and spiked soils. Absolute and relative bioavailability of Pb in soils (oral dose of 100 µ g Pb/kg body weight/day) were estimated by comparing them with intravenously administered soluble Pb salt (25 µ g Pb/kg/day) and orally administered the same Pb salt [Pb acetate =(CH COO) Pb·3H O] administered to 3 juvenile pigs per treatment. Lead bioaccessibility was calculated using the in vitro RBALP (i.e. relative bioaccessibility leaching procedure) method. The in vitro results of RBALP were compared to in vivo relative Pb bioavailability to ascertain whether the changes in bioaccessibility correlated with the in vivo data. Although the in vivo Pb relative bioavailability (RB) in all soils except in MLA (Mount Lofty Acidic) revealed an increase (18%¿159%) in the presence of Zn, the in vitro RBALP bioaccessibility results indicated otherwise (1%¿38% decrease). In vivo RB of Pb in MLA declined by 37% in the presence of Zn. However, the RBALP in vitro bioaccessible Pb did not correlate with the relative bioavailabilities of Pb in the juvenile swine dosing experiment. Caution is therefore needed when predicting Pb bioavailability/bioaccessibility in the presence of metal mixtures. The literature contains much information on the correlation of metal and metalloid bioaccessibility with their bioavailability. There is, however, a paucity of studies investigating the effects of other metals on Pb and their IVIVC (in vitro and in vivo correlations). The current study addresses this knowledge gap by assessing in vivoand in vitro bioavailability of Pb in the presence of Zn. 3 2 2

Arsenic (As) and zinc (Zn) are common co-contaminants in mining impacted soils. Their interaction on solubility and toxicity when present concurrently is not well understood in natural systems. The aim of this study was to observe their interaction in solubility (soil-solution), bioaccumulation (shoot uptake) and toxicity to cucumber (Cucumis sativa L) conducting 4 weeks pot study in 5 different soils spiked with As (0, 2, 4, 8 to 1024 mg kg ) individually and with Zn at two phytotoxic doses. The As pore-water concentration was significantly reduced (df = 289, Adjusted R = 0.84, p < 0.01) in the presence of Zn in the whole dataset, whereas Zn and Zn activity in pore-water was reduced significantly only in the two alkaline soils. This outcome may be due to adsorption/surface precipitation or tertiary bridging complexation. No homogenous precipitation of zinc arsenate could be established using electron microscopy, XRD or even equilibrium calculations. For bioaccumulation phase, no significant effect of Zn on As uptake was observed except acidic MG soil whereas, Zn uptake was significantly reduced (p < 0.05) by As in whole dataset. However, an additive response was observed mostly except acidic MG soil. The synergistic response (more than additive) was predominant in this soil for a wide range of inhibition concentration (0¿80%) at both Zn EC10 and EC50 levels. Since additive response is mostly considered in risk assessment for mixtures, precautions should be implemented for assessment of toxicity for As-Zn mixture in acidic soil due to their synergistic response in some soils. -1 2 2+

Barite contamination of soil commonly occurs from either barite mining or explorative drilling operations. This work reported in vitro data for barite contaminated soils using the physiologically based extraction test (PBET) methodology. The existence of barite in plant tissue and the possibility of 'biomineralised' zones was also investigated using Scanning Electron Microscopy. Soils with low barium (Ba) concentrations showed a higher proportion of Ba extractability than barite rich samples. Barium uptake to spinach from soil was different between short term spiking studies and field weathered soils. Furthermore, Ba crystals were not evident in spinach tissue or acid digest solutions grown in barium nitrate spiked soils despite high accumulation. Barite was found in the plant digest solutions from barite contaminated soils only. Results indicate that under the conservative assumptions made, a child would need to consume extreme quantities of soil over an extended period to cause chronic health problems.

Recent decades have seen a growing popularity of in vitro bioaccessibility being utilised as a screening tool in human health risk assessment. However the existing bioaccessibility studies only focus on single contaminant. Considering human are likely to ingest multi-contaminants, these contaminants could interact within human gastrointestinal tract which may lead to an increase or decrease in bioaccessibility. In this study, seven different types of soil were spiked with arsenic (As) or cadmium (Cd) and aged for one year. The effects of soil properties on the bioaccessibility were examined. Moreover, the interaction between As and Cd in simulated human digestive system was studied by mixing As-spiked soil with Cd-spiked soil of the same type during bioaccessibility test. Results shows the bioaccessibility of As ranged from 40 ± 2.8 to 95 ± 1.3% in the gastric phase and 16 ± 2.0 to 96 ± 0.8% in the intestinal phase whilst a significant difference was observed between Cd gastric bioaccessibility (72 ± 4.3 to 99 ± 0.8%) and intestinal bioaccessibility (6.2 ± 0.3 to 45 ± 2.7%). Organic carbon, iron oxide and aluminium oxide were key parameters influencing the bioaccessibility of As (gastric and intestinal phases) and Cd (intestinal phase). No interactions between As and Cd during bioaccessibility test were observed in any soils, which indicates As and Cd may age independently and did not interact while being solubilised during bioaccessibility test. Thus additive effect may be proposed when estimating the bioaccessibility of mixtures of independently-aged As and Cd in soils.

Arsenic (As) is a mobile and ecotoxic metalloid that is of serious concern to the environment. In this study, As phytotoxicity was studied using a dose-response approach for seven contrasting soils considering 3 end-points (shoot biomass, root elongation and chlorophyll content) and focusing on predictors of toxicity. Root elongation study was carried out for 4days using both Cucumis sativus L. (cucumber) and Triticum aestivum L. (wheat) and shoot end-points with a 4week a pot study using cucumber only. Root elongation of cucumber was a substantially less sensitive indicator to As than data from the 4weeks pot study. Effective concentrations (50%)(EC ) from cucumber root elongation studies were overall 1.6 times higher than the 4week shoot data. Cucumber was however considerably more sensitive to wheat. Given the large discrepancy in phytotoxicity end points for 7 soils, root elongation data for ecotoxicological assessment should be treated with some caution. Arsenic phytotoxicity was strongly related to the sorption constants of each of the seven soils in our study. Both root elongation and shoot data were related strongly to Freundlich partitioning constants (K ) (L/kg). Wheat and cucumber root elongation had R values 0.90 and 0.91 respectively, while cucumber shoot data was 0.79. The K values were related to soil pH and also EC data and, thus, shows that As phytotoxicity in our study was primarily controlled by sorption reactions. The rate of As bioaccumulation to cucumber shoots depended heavily on the soil under consideration. Chlorophyll and carotenoid content of cucumber shoots increased with As content in 3 soils and decreased in other soils. 50 f f 50 2

The sorption behavior of cadmium (Cd(II)) and zinc (Zn(II)) on two virgin soils with different pH levels was studied using single metal and competitive dual metal systems. In the single metal system, Zn exhibited a greater affinity for the alkaline soil, as indicated by the Langmuir constant (K = 8.85 L/kg) compared with Cd (K = 1.79 L/kg). However, much less sorption of both Zn (K = 0.19 L/kg) and Cd (K = 0.07 L/kg) was observed in the acidic soil. The competitive sorption data were modeled using two-metal Freundlich and Langmuir functions. The competition for metal sorption occurred in the alkaline soil only at a higher concentration of the competing metals, whereas the effect was significant even at lower concentrations in the acidic soil. The cumulative amount of both metals sorbed in the soil was similar to that of single metal systems in the studied concentration range, demonstrating that the number of sites available for sorption remained constant irrespective of the competition. This study indicated that Cd might be more mobile in a mixed-metal system than in a single-metal scenario and thus poses a serious ecotoxicological threat. This study is important for assessing the risks and developing management strategies for multiple heavy metal contaminated soils. L L L L

Zinc (Zn) is a widespread soil contaminant arising from a numerous anthropogenic sources. However, adequately predicting toxicity of Zn to ecological receptors remains difficult due to the complexity of soil characteristics. In this study, we examined solid-solution partitioning using pore-water data and toxicity of Zn to cucumber (Cucumis sativus L.) in spiked soils. Pore-water effective concentration (ECx, x=10%, 20% and 50% reduction) values were negatively related to pH, indicating lower Zn pore water concentration were needed to cause phytotoxicity at high pH soils. Total dissolved zinc (Zn<inf>pw</inf>) and free zinc (Zn²⁺) in soil-pore water successfully described 78% and 80.3% of the variation in relative growth (%) in the full dataset. When the complete data set was used (10 soils), the estimated EC50<inf>pw</inf> was 450 and 79.2µM for Zn<inf>pw</inf> and Zn²⁺, respectively. Total added Zn, soil pore water pH (pH<inf>pw</inf>) and dissolve organic carbon (DOC) were the best predictors of Zn<inf>pw</inf> and Zn²⁺ in pore-water. The EC10 (total loading) values ranged from 179 to 5214mg/kg, depending on soil type. Only pH measurements in soil were related to ECx total Zn data. The strongest relationship to ECx overall was pH<inf>ca</inf>, although pH<inf>w</inf> and pH<inf>pw</inf> were in general related to Zn ECx. Similarly, when a solution-only model was used to predict Zn in shoot, DOC was negatively related to Zn in shoot, indicating a reduction in uptake/ translocation of Zn from solution with increasing DOC.

This study introduced a patented novel methodological system for automatically analysis of Fourier Transform Infrared Spectrometer (FTIR) spectrum data located at 'fingerprint' region (wavenumber 670-800 cm ), to simultaneously determinate multiple petroleum hydrocarbons (PHs) in real mixture samples. This system includes: an object oriented baseline correction; Band decomposition (curve fitting) method with mathematical optimization; and Artificial Neural Network (ANN) for determination, which is suitable for the characteristics of this IR regions, where the spectra are normally with low signal to noise ratio and high density of peaks. BTEX components are potentially lethal carcinogens and contained in many petroleum products. As a case study, six BTEX components were determinate automatically and simultaneously in mixture vapor samples. The robustness of the BTEX determination was validated using real petroleum samples, and the prediction results were compared with gas chromatography-mass spectrometry (GC-MS). -1

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 SO and PO , 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 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. 4 4 f 2- 3-

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.

The effects of pH and Cu loading on the solid/solution partitioning of Cu in a Podosol from south-east Queensland, Australia was examined. Sorption-desorption of Cu exhibited maximum linear distribution coefficients (K ) at approximately pH 5. Observed decrease in K values at pH >5 was attributed to increased solubility of native dissolved organic carbon (DOC) at higher pH and subsequent formation of non-sorbing Cu-DOC complexes. Speciation modelling with the MINTEQA2 code indicated that >90% of aqueous Cu was present as Cu-DOC complexes at pH >5.5. The effect of Cu loading was examined with sorption isotherm analysis at pH 5 using solid:solution ratio approaches that were both constant (1:2 and 1:10) and variable. As the solid:solution ratio increased, the proportion of Cu sorbed decreased due to the formation of Cu-DOC complexes. However, this effect was negligible once these Cu-DOC complexes were accounted for via free Cu sorption isotherms. This indicated that Cu sorption at concentrations <0.08 mg/L was described by a K value of approximately 3000 L/kg. Despite this relatively high K value for Cu sorption, the results indicate that Cu-DOC complexes significantly enhance Cu solubility in soils high in DOC. © CSIRO 2005. D D D D 2+ 2+ 2+

The sorption-desorption and leaching behaviour of Cu in a Podosol from south-east Queensland, Australia, was examined. Copper sorption was described by a linear distribution coefficient at low sorption levels (K ) of 481 L/kg and a sorption capacity (C ) of 382 mg/kg. Selective removal of soil organic matter reduced these values by approximately 95%, indicating that Cu was sorbed predominantly to soil organic matter. The K and C values from Cu desorption experiments were 934 L/kg and 516 mg/kg, respectively, which indicates that sorption was not fully reversible. This irreversibility was related to aqueous Cu speciation (modelled with MINTEQA2), showing that aqueous complexes between Cu and dissolved organic carbon (DOC) comprised 28.3-72.8% and 21.3-45.4% of aqueous Cu in the sorption and desorption experiment, respectively. Sorption irreversibility was not evident when the corresponding data was presented as free Cu isotherms. Both sorption and desorption experiments with free Cu <0.2 mg/L were described by a K value of approximately 3000 L/kg. Sequential extraction of sorbed Cu indicated that at low concentrations, sorption occurred primarily via specific interactions, with non-specific sorption becoming increasing important at higher concentrations. Desorption of Cu in a column leaching experiment was attributable to exchange of sorbed Cu with Na . Leaching with a DOC solution of pH 7 and 135 mg/L greatly enhanced Cu mobility due to the formation of aqueous Cu-DOC complexes. © CSIRO 2005. D S,Max D S,Max D Ca¿0 Ca¿0 2+ 2+ Ca¿0 2+ +