Cooperative Research Center for Contamination Assessment

Mawson Lakes, Australia

Cooperative Research Center for Contamination Assessment

Mawson Lakes, Australia
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Abu-Bakar A.,University of Queensland | Arthur D.M.,University of Queensland | Arthur D.M.,Cooperative Research Center for Contamination Assessment | Aganovic S.,Uppsala University | And 4 more authors.
Toxicology and Applied Pharmacology | Year: 2011

We have previously shown that bilirubin (BR), a breakdown product of haem, is a strong inhibitor and a high affinity substrate of the mouse cytochrome P450 2A5 (CYP2A5). The antioxidant BR, which is cytotoxic at high concentrations, is potentially useful in cellular protection against oxygen radicals if its intracellular levels can be strictly controlled. The mechanisms that regulate cellular BR levels are still obscure. In this paper we provide preliminary evidence for a novel function of CYP2A5 as hepatic "BR oxidase". A high-performance liquid chromatography/electrospray ionisation mass spectrometry screening showed that recombinant yeast microsomes expressing the CYP2A5 oxidise BR to biliverdin, as the main metabolite, and to three other smaller products with m/. z values of 301, 315 and 333. The metabolic profile is significantly different from that of chemical oxidation of BR. In chemical oxidation the smaller products were the main metabolites. This suggests that the enzymatic reaction is selective, towards biliverdin production. Bilirubin treatment of primary hepatocytes increased the CYP2A5 protein and activity levels with no effect on the corresponding mRNA. Co-treatment with cycloheximide (CHX), a protein synthesis inhibitor, resulted in increased half-life of the CYP2A5 compared to cells treated only with CHX. Collectively, the observations suggest that the CYP2A5 is potentially an inducible "BR oxidase" where BR may accelerate its own metabolism through stabilization of the CYP2A5 protein. It is possible that this metabolic pathway is potentially part of the machinery controlling intracellular BR levels in transient oxidative stress situations, in which high amounts of BR are produced. © 2011.

Kuang Y.,Fujian Normal University | Zhou Y.,Fujian Normal University | Chen Z.,Fujian Normal University | Megharaj M.,University of South Australia | And 3 more authors.
Bioresource Technology | Year: 2013

The Bacillus fusiformis (BFN) strain and its biodegradation of phenol when iron-based nanoparticles such as nanoscale zero-valent iron (nZVI) and Ni/Fe nanoparticles (Ni/Fe) were present at different pH values (6.0, 8.0, and 3.0) were investigated. The growth of BFN and its biodegradation of phenol accelerated in the presence of nZVI and Ni/Fe both at pH 8.0 and pH 6.0. The H2 generated by the corrosion of iron can be used as an electron donor and source of energy for growing BFN. However, only nZVI improved the biodegradation of phenol at pH 3.0, which is most likely due to the increasing medium pH value resulting from the generation of OH- as a result of iron corrosion. The images from scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) demonstrated that these iron-based nanoparticles adhered to the surface of BFN, but no significant change in the morphology of BFN was observed. © 2013 Elsevier Ltd.

Chen Z.-X.,Fujian Normal University | Jin X.-Y.,Fujian Normal University | Chen Z.,Fujian Normal University | Chen Z.,University of South Australia | And 5 more authors.
Journal of Colloid and Interface Science | Year: 2011

Zero-valent iron (ZVI) nanoparticles tend to agglomerate, resulting in a significant loss in reactivity. To address this issue, synthesized bentonite-supported nanoscale zero-valent iron (B-nZVI) was used to remove azo dye methyl orange (MO) in aqueous solution. Batch experiments show that various parameters, such as pH, initial concentration of MO, dosage, and temperature, were affected by the removal of MO. Scanning electron microscopy (SEM) confirmed that B-nZVI increased their reactivity and a decrease occurred in the aggregation of iron nanoparticles for the presence of bentonite (B). Using B-nZVI, 79.46% of MO was removed, whereas only 40.03% when using nZVI after reacting for 10. min with an initial MO concentration of 100. mg/L (pH = 6.5). Furthermore, after B-nZVI reacted to MO, XRD indicated that iron oxides were formed. FTIR showed that no new bands appeared, and UV-vis demonstrated that the absorption peak of MO was degraded. Kinetics studies showed that the degradation of MO fitted well to the pseudo first-order model. A degradation mechanism is proposed, including the following: oxidation of iron, adsorption of MO to B-nZVI, formation of Fe(II)-dye complex, and cleavage of azo bond. Finally, the removal rate of MO from actual wastewater was 99.75% when utilizing B-nZVI. © 2011 Elsevier Inc.

Bolan N.,University of South Australia | Bolan N.,Cooperative Research Center for Contamination Assessment | Kunhikrishnan A.,National Academy of Agricultural Science | Thangarajan R.,University of South Australia | And 6 more authors.
Journal of Hazardous Materials | Year: 2014

Unlike organic contaminants, metal(loid)s do not undergo microbial or chemical degradation and persist for a long time after their introduction. Bioavailability of metal(loid)s plays a vital role in the remediation of contaminated soils. In this review, the remediation of heavy metal(loid) contaminated soils through manipulating their bioavailability using a range of soil amendments will be presented. Mobilizing amendments such as chelating and desorbing agents increase the bioavailability and mobility of metal(loid)s. Immobilizing amendments such of precipitating agents and sorbent materials decrease the bioavailabilty and mobility of metal(loid)s. Mobilizing agents can be used to enhance the removal of heavy metal(loid)s though plant uptake and soil washing. Immobilizing agents can be used to reduce the transfer to metal(loid)s to food chain via plant uptake and leaching to groundwater. One of the major limitations of mobilizing technique is susceptibility to leaching of the mobilized heavy metal(loid)s in the absence of active plant uptake. Similarly, in the case of the immobilization technique the long-term stability of the immobilized heavy metal(loid)s needs to be monitored. © 2013 Elsevier B.V.

Park J.H.,University of South Australia | Park J.H.,Cooperative Research Center for Contamination Assessment | Park J.H.,University of Queensland | Choppala G.K.,University of South Australia | And 6 more authors.
Plant and Soil | Year: 2011

Background and aims: Biochar has attracted research interest due to its ability to increase the soil carbon pool and improve crop productivity. The objective of this study was to evaluate the metal immobilizing impact of chicken manure- and green waste-derived biochars, and their effectiveness in promoting plant growth. Methods: The immobilization and phytoavailability of Cd, Cu and Pb was examined using naturally contaminated shooting range and spiked soils. Biochar samples prepared from chicken manure and green waste were used as soil amendments. Results: Application of biochar significantly reduced NH4NO3 extractable Cd, Cu and Pb concentrations of soils, indicating the immobilization of these metals. Chicken manure-derived biochar increased plant dry biomass by 353 and 572% for shoot and root, respectively with 1% of biochar addition. This might be attributed to reduced toxicity of metals and increased availability of nutrients such as P and K. Both biochars significantly reduced Cd, Cu and Pb accumulation by Indian mustard (Brassica juncea), and the reduction increased with increasing amount of biochar application except Cu concentration. Metal sequential fractionation data indicated that biochar treatments substantially modified the partitioning of Cd, Cu and Pb from the easily exchangeable phase to less bioavailable organic bound fraction. Conclusions: The results clearly showed that biochar application was effective in metal immobilization, thereby reducing the bioavailability and phytotoxicity of heavy metals. © 2011 Springer Science+Business Media B.V.

Kiddee P.,University of South Australia | Kiddee P.,Cooperative Research Center for Contamination Assessment | Naidu R.,University of South Australia | Naidu R.,Cooperative Research Center for Contamination Assessment | Wong M.H.,Hong Kong Baptist University
Waste Management | Year: 2013

Electronic waste (e-waste) is one of the fastest-growing pollution problems worldwide given the presence if a variety of toxic substances which can contaminate the environment and threaten human health, if disposal protocols are not meticulously managed. This paper presents an overview of toxic substances present in e-waste, their potential environmental and human health impacts together with management strategies currently being used in certain countries. Several tools including Life Cycle Assessment (LCA), Material Flow Analysis (MFA), Multi Criteria Analysis (MCA) and Extended Producer Responsibility (EPR) have been developed to manage e-wastes especially in developed countries. The key to success in terms of e-waste management is to develop eco-design devices, properly collect e-waste, recover and recycle material by safe methods, dispose of e-waste by suitable techniques, forbid the transfer of used electronic devices to developing countries, and raise awareness of the impact of e-waste. No single tool is adequate but together they can complement each other to solve this issue. A national scheme such as EPR is a good policy in solving the growing e-waste problems. © 2013 .

Bahar M.M.,University of South Australia | Bahar M.M.,Cooperative Research Center for Contamination Assessment | Megharaj M.,University of South Australia | Megharaj M.,Cooperative Research Center for Contamination Assessment | And 2 more authors.
Journal of Hazardous Materials | Year: 2013

A Gram-negative, arsenite-oxidizing bacterial strain, MM-1 tolerant to 20mM arsenite and 200mM arsenate was isolated from a heavy metal contaminated soil which contained only 8.8mgkg-1 of arsenic. Based on 16S rRNA analysis, the strain was closely related to the genus Variovorax. This strain completely oxidized 500μM of arsenite to arsenate within 3h of incubation in minimal salts medium. Kinetic studies of arsenite oxidation by the cells showed one of the lowest Km (17μM) and highest Vmax (1.23×10-7μMmin-1cell-1) values reported to date for whole cell suspension. PCR analysis using degenerate primers confirmed the presence of arsenite oxidase gene and its amino acid sequence was 70-91% identical to the large subunit of most reported arsenite oxidases. The significant arsenite oxidation capacity shown by the strain opens the way to its potential application in arsenic remediation process. © 2012 Elsevier B.V.

Park J.H.,University of South Australia | Park J.H.,Cooperative Research Center for Contamination Assessment | Lamb D.,University of South Australia | Lamb D.,Cooperative Research Center for Contamination Assessment | And 7 more authors.
Journal of Hazardous Materials | Year: 2011

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.

Rahman M.M.,University of South Australia | Rahman M.M.,Cooperative Research Center for Contamination Assessment | Asaduzzaman M.,University of South Australia | Asaduzzaman M.,Cooperative Research Center for Contamination Assessment | And 2 more authors.
Journal of Hazardous Materials | Year: 2013

The study assesses the daily consumption by adults of arsenic (As) and other elements in drinking water and home-grown vegetables in a severely As-contaminated area of Bangladesh. Most of the examined elements in drinking water were below the World Health Organization (WHO) guideline values except As. The median concentrations of As, cadmium (Cd), chromium (Cr), cobalt (Co), copper (Cu), lead (Pb), Mn, nickel (Ni), and zinc (Zn) in vegetables were 90μgkg-1, 111μgkg-1, 0.80mgkg-1, 168μgkg-1, 13mgkg-1, 2.1mgkg-1, 65mgkg-1, 1.7mgkg-1, and 50mgkg-1, respectively. Daily intakes of As, Cd, Cr, Co, Cu, Pb, manganese (Mn), Ni, and Zn from vegetables and drinking water for adults were 839μg, 2.9μg, 20.8μg, 5.5μg, 0.35mg, 56.4μg, 2.0mg, 49.1μg, and 1.3mg, respectively. The health risks from consuming vegetables were estimated by comparing these figures with the WHO/FAO provisional tolerable weekly or daily intake (PTWI or PTDI). Vegetables alone contribute 0.05μg of As and 0.008mg of Cu per kg of body weight (bw) daily; 0.42μg of Cd, 8.77mg of Pb, and 0.03mg of Zn per kg bw weekly. Other food sources and particularly dietary staple rice need to be evaluated to determine the exact health risks from such foods. © 2012 Elsevier B.V.

Juhasz A.L.,University of South Australia | Juhasz A.L.,Cooperative Research Center for Contamination Assessment | Weber J.,University of South Australia | Weber J.,Cooperative Research Center for Contamination Assessment | And 2 more authors.
Journal of Hazardous Materials | Year: 2011

In this study, As-contaminated soils (n=12) were assessed for As bioaccessibility using the Unified Bioaccessibility Research Group of Europe in vitro method (UBM) incorporating gastric, saliva-gastric or saliva-gastric-intestinal phases. Arsenic bioaccessibility was compared to previous published As relative bioavailability data for these soils to determine the correlation between in vitro and in vivo data. Comparison of in vitro and in vivo data indicated that the correlation between As bioaccessibility (UBM) and As relative bioavailability (swine assay) was similar irrespective of the in vitro phase used for its determination. The UBM incorporating all phases (saliva-gastric-intestinal) provided the best in vivo-in vitro correlation (slope=1.08; R 2=0.59), however there was no significant difference in the goodness of fit (R 2 ranged from 0.48 to 0.59) or the slope of the lines (0.93-1.08) for either variation of the UBM (P=0.9946). This indicates that there was no improvement in the As relative bioavailability predictive capabilities when the UBM was extended from a single gastric phase to saliva-gastric or saliva-gastric-intestinal phases. © 2011 Elsevier B.V.

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