Halogenated organic compounds constitute one of the largest groups of environmental pollutants. These toxic, bioaccumulating pollutants include legacy industrial chemicals, such as polychlorinated biphenyls (PCBs), ubiquitous polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) which continually enter the environment via anthropogenic and natural inputs, as well as current commercial manufacturing chemicals including the brominated flame retardants (BFRs). These widespread use and application has resulted in widespread dissemination and environmental contamination, with estuarine and marine sediments as significant sinks. Organohalide contaminants can enter the food chain through various routes, threaten human health and may ultimately accumulate in sediments and soils. These pollutants are problematic due to their recalcitrance and toxicity, and furthermore, are often present as complex mixtures. Consequently, the management of sediments and soils contaminated with toxic organohalide compounds, including PCDD/Fs, PCBs, pesticides and brominated flame retardants, is a major problem with far-reaching economic and ecological consequences. Remediation of soils and sediments contaminated with these toxic chemicals continues to be a major challenge. New methods are needed for in situ containment and degradation of contaminants. The overall goal of this project is to identify the microbial communities responsible for anaerobic reductive dehalogenation of organohalide compounds, including brominated flame retardants, polychlorinated dibenzo-p-dioxins, polychlorinated biphenyls and diverse pesticides. The knowledge base will lay a foundation for development of technologies for bioremediation of contaminated sediments. Enhancement of microbial dehalogenation in situ is an attractive remediation alternative that could potentially detoxify soils and sediments. Anaerobic biological dechlorination offers a promising approach towards eventual detoxification and complete degradation of halogenated contaminant mixtures. Detailed information on the dehalogenation process is needed to provide strategies for remediation of contaminated sediments by enhancing dehalogenation of organohalogen pollutants in situ and/or for example in conjunction with sediment caps. Stimulation of natural populations of dehalogenating bacteria and bioaugmentation of soils and sediments using specialized dehalogenating bacterial strains holds promise for development of new in situ or ex situ remedial approaches for sediments. The expected outcome of the proposed research is the development of in situ amendment strategies that enhance microbial activity through the identification and characterization of microorganisms that dehalogenate diverse organohalide contaminant mixtures. The study will greatly enhance our understanding of the fate of organohalide contaminants by supplying fundamental information about the microorganisms and genes involved in dehalogenation and other biotransformations.
|Effective start/end date||10/1/11 → 9/30/16|
- National Institute of Food and Agriculture (National Institute of Food and Agriculture (NIFA))