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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.

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.

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 .

Kunhikrishnan A.,University of South Australia | Kunhikrishnan A.,Cooperative Research Center for Contamination Assessment | Kunhikrishnan A.,National Academy of Agricultural Science | Bolan N.S.,University of South Australia | And 6 more authors.
Advances in Agronomy | Year: 2012

With pressure increasing on potable water supplies worldwide, interest in using alternative water supplies including recycled wastewater for irrigation purposes is growing. Wastewater is derived from a number of sources including domestic sewage effluent or municipal wastewater, agricultural (farm effluents) and industrial effluents, and stormwater. Although wastewater irrigation has many positive effects like reliable water supply to farmers, better crop yield, pollution reduction of rivers, and other surface water resources, there are problems associated with it such as health risks to irrigators, build-up of chemical pollutants (e.g., heavy metal(loid)s and pesticides) in soils and contamination of groundwater. Since the environment comprises soil, plants, and soil organisms, wastewater use is directly associated with environmental quality due to its immediate contact with the soil-plant system and consequently can impact on it. For example, the presence of organic matter in wastewater-irrigated sites significantly affects the mobility and bioavailability of heavy metal(loid)s in the soil. Wastewater irrigation can also act as a source of heavy metal(loid) input to soils. In this chapter, first, the various sources of wastewater irrigation and heavy metal(loid) input to soil are identified; second, the effect of wastewater irrigation on soil properties affecting heavy metal(loid) interactions is described; and third and finally, the role of wastewater irrigation on heavy metal(loid) dynamics including adsorption and complexation, redox reactions, transport, and bioavailability is described in relation to strategies designed to mitigate wastewater-induced environmental impacts. © 2012 Elsevier Inc.

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.

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