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Kuppusamy S.,University of South Australia | Kuppusamy S.,Cooperative Research Center for Contamination Assessment and Remediation of Environment | Thavamani P.,Cooperative Research Center for Contamination Assessment and Remediation of Environment | Thavamani P.,University of Newcastle | And 4 more authors.
Water, Air, and Soil Pollution | Year: 2016

Treatability studies in real contaminated soils are essential to predict the feasibility of microbial consortium augmentation for field-scale bioremediation of contaminated sites. In this study, the biodegradation of a mixture of seven PAHs in a manufactured gas plant (MGP) soil contaminated with 3967 mg kg-1 of total PAHs using novel acid-, metal-tolerant, N-fixing, P-solubilizing, and biosurfactant-producing LMW and HMW PAH-degrading bacterial combinations as inoculums was compared in slurry- and solid-phase microcosms over natural attenuation. Bioaugmentation of 5 % of bacterial consortia A and N in slurry- and solid-phase systems enhanced 4.6-5.7 and 9.3-10.7 % of total PAH degradation, respectively, over natural attenuation. Occurrence of 62.7-88 % of PAH biodegradation during natural attenuation in soil and slurry illustrated the accelerated rate of intrinsic metabolic activity of the autochthonous microbial community in the selected MGP soil. Monitoring of the total microbial activity and population of PAH degraders revealed that the observed biodegradation trend in MGP soil resulted from microbial mineralization. In the slurry, higher biodegradation rate constant (k) and lower half-life values (t 1/2) was observed during bioaugmentation with consortium N, highlighting the use of bioaugmentation in bioslurries/bioreactor to achieve rapid and efficient bioremediation compared to that of a static solid system. In general, natural attenuation was on par with bioaugmentation. Hence, depending on the type of soil, natural attenuation might outweigh bioaugmentation and a careful investigation using laboratory treatability studies are highly recommended before the upscale of a developed bioremediation strategy to field level. © 2015 Springer International Publishing Switzerland. Source


Yang D.,University of South Australia | Wang L.,University of South Australia | Chen Z.,University of South Australia | Megharaj M.,University of South Australia | And 3 more authors.
Microchimica Acta | Year: 2014

We report on a glassy carbon electrode modified with bismuth nanoparticles (NanoBiE) for the simultaneous determination Pb2+ and Cd2+ by anodic stripping voltammetry. Operational parameters such as bismuth nanoparticles labelling amount, deposition potential, deposition time and stripping parameters were optimized with respect to the determination of Pb2+ and Cd2+ in 0.1 M acetate buffer solution (pH 4.5). The NanoBiE gives well-defined, reproducible and sharp stripping peaks. The peak current response increases linearly with the metal concentration in a range of 5.0-60.0 μg L-1, with a detection limit of 0.8 and 0.4 μg L-1 for Pb2+ and Cd2+, respectively. The morphology and composition of the modified electrode before and after voltammetric measurements were analysed by scanning electron microscopy and energy dispersive X-ray analysis. The NanoBiE was successfully applied to analysis of Pb2+ and Cd2+ in real water samples and the method was validated by ICP-MS technique, suggesting that the electrode can be considered as an interesting alternative to the bismuth film electrode for possible use in electrochemical studies and electroanalysis. [Figure not available: see fulltext.] © 2014 Springer-Verlag Wien. Source


Yang D.,University of South Australia | Wang L.,University of South Australia | Chen Z.,University of South Australia | Megharaj M.,University of South Australia | And 3 more authors.
Electroanalysis | Year: 2014

A new chemically modified bismuth film electrode coated with an ionic liquid [(1-ethyl-3-methylimidazolium tetracyanoborate (EMIM TCB)] and Nafion was developed for the simultaneous determination Pb2+ and Cd2+ by anodic stripping voltammetry. Compared with conventional bismuth film electrodes, this electrode exhibited greatly improved electrochemical activity for Pb2+ and Cd2+ detection due to the unique properties of Nafion polymer and ionic liquid. The key experimental parameters related to the fabrication of the electrode and the voltammetric measurements were optimized on the basis of the stripping signals, where the peak currents increased linearly with the metal concentrations in a range of 10-120μgL-1 with a detect limit of 0.2μgL-1 for Pb2+, and 0.5μgL-1 for Cd2+ for 120s deposition. High reproducibility was indicated from the relative standard deviations (1.9 and 2.5%) for nine repetitive measurements of 20μgL-1 Pb2+ and Cd2+, respectively. In addition, the surface characteristics of the modified BiFE were investigated by scanning electron microscopy (SEM), and results showed that fibril-like bismuth nanostructures were formed on the porous Nafion polymer matrix. Finally, the developed electrode was applied to determine Pb2+ and Cd2+ in water samples, indicating that this electrode was sensitive, reliable and effective for the simultaneous determination of Pb2+ and Cd2+. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Ramakrishnan B.,Indian Central Rice Research Institute | Megharaj M.,University of South Australia | Megharaj M.,Cooperative Research Center for Contamination Assessment and Remediation of Environment | Venkateswarlu K.,Sri Krishnadevaraya University | And 3 more authors.
Critical Reviews in Environmental Science and Technology | Year: 2010

Efforts are continuously being made to understand the non-target effects of environmental pollutants toward microalgae and cyanobacteria because of their ubiquity in aquatic and terrestrial environments and their highly adaptive survival abilities under environmental and evolutionary pressure over geological time. Depending on the toxicity criteria employed for these ecologically beneficial organisms, the impact of low and high doses of pollutants can range from stimulation to total inhibition. All of the investigations carried out so far have been predominantly concerned with individual chemicals despite the occurrence of pollutants in mixtures. In addition, only individual isolates have been primarily used to gather scientific information on the toxicity of pollutants. The risk assessment of pollutants toward these organisms necessitates further investigations, combining innovative molecular ecological methods and those for in situ analysis at the community level. The present review highlights the toxic influences of organic and inorganic pollutants and the response in terms of detoxification and resistance by these organisms. Copyright © 2010 Taylor and Francis Group, LLC. Source


Yang D.,University of South Australia | Wang L.,University of South Australia | Chen Z.,University of South Australia | Megharaj M.,University of South Australia | And 3 more authors.
Electroanalysis | Year: 2013

The bismuth-coated electrode is known to be prone to errors caused by copper(II). This study investigates copper(II) interference at bismuth film electrode for the detection of lead(II) and cadmium(II). It was conducted using glassy carbon electrode, while the bismuth film was plated in situ simultaneously with the target metal ions at -1200mV. Copper(II) presented in solution significantly reduced the sensitivity of the electrode, for example there was an approximately 70% and 90% decrease in peak signals for lead(II) and cadmium(II), respectively, at a 10-fold molar excess of copper(II). The decrease in sensitivity was ascribed to the competition between copper and bismuth or the metal ions for surface active sites. Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis suggested a large decrease in the amount of bismuth nanoparticles formed on the electrode surface in the presence of copper(II) occurred, validating the competition between copper and bismuth ions for surface active sites. Recovery of the stripping signal of lead(II) and cadmium(II) was obtained by adding ferrocyanide ion to the solution. Finally, the proposed method was successfully applied to determine lead(II) and cadmium(II) in water samples and the method was validated by ICP-MS technique. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

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