Biodegradation Of Irradiated Toxic Aromatic Compounds
Special Symposium - Environmental Protection & Sustainability
Environmental Protection & Sustainability - I
Keywords: Biodegradation, radioactive waste, radionuclides, irradiated organic compounds, Phenol
Radioactive wastes are mostly generated from applications of nuclear technology in energy, medicine, agriculture and industrial applications and from activities of ores and production and processing of oil and gas. Uncontrolled release of radioactive wastes from medical and industrial application, from nuclear reprocessing plants and from production of nuclear weapons still pose many problems to human life and the natural environment due to its toxicity and the long half-lives of the radioisotopes. There has been an increased interest in the use of microorganisms for the treatment of contaminated sediments and waters impacted by nuclear waste due to the perceived cost-effectiveness and efficiency of biological systems over the currently used chemical-based methods (Gadd, 1996; Sar et al. 2004; Lloyd and Renshaw, 2005).
There is minimal information on the bioremediation of the radioactive waste let alone biodegradation of irradiated organic compounds. The irradiated organic pollutants, even if not severely radioactive, are mostly toxic and hard to degrade (recalcitrant) in nature. Irradiated organics and radioactive actinides occur as mixed wastes which poise disposal challenges since different regulatory requirements apply for the disposal of radioactive wastes and hazardous conventional wastes (Roberts, 1998). The problem is further compounded, if there is a mixture of organic compounds in the radioactive waste. Other compounds in the mixture may inhibit the degradation of one component and different conditions may be required to treat different compounds in the mixture. Hence there is a need to consider these pollutants when deciding a suitable disposal option for radioactive waste.
In this study, the biodegradation pathways of organic compounds discharged together with radioactive waste are investigated. A mixture of organic pollutants (phenol and toluene) and major radionuclides (137Cs, 60Coand 90Sr) are used to stimulate the organic radioactive waste. Phenol and toluene will be used in the study as model compound due the simplified structure and due to the fact that their biodegradation pathways generally known. Biodegradation studies are carried out using pure and mixed cultures. Biodegradation and substrate-level inhibition kinetic models will be developed and validated using results from this study.
The outcome of this study will be useful in the understanding of degree of interaction between the radionuclides and the organic pollutants during the biodegradation of the organic compound.
See the full pdf manuscript of the abstract.
