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Biology of Methanogenesis |
Department of Marine Biotechnology UMBC - Institute of Marine & Environmental Technology
Biostimulation and electrolytic aeration to degrade POPs
Due to the their
widespread use and stability, sediments contaminated with persistent organic
pollutants (POPs) such as polychlorinated biphenyls, chlorobenzenes and
dioxins have been an environmental concern for several decades. In addition
to perturbing the benthic community, these compounds biomagnify in the food
chain through accumulation in the fatty tissue of animals, such as fish and
marine mammals, which can eventually affect humans if consumed. Exposure to
halogenated POPs by humans can lead to dermal toxicity, teratotoxicity,
endocrine effects, hepatotoxicity, immunotoxicity, and carcinogenesis.
Although chemically stable in the environment these highly chlorinated
compounds are susceptible to degradation once most of their chlorines are
removed. The initial dechlorination is catalyzed in the anaerobic
environment by microbial reductive respiration; the products of this initial
microbial process can then be degraded and detoxified by oxygen respiring
microorganisms. The limitations of these processes are: 1) anaerobic
dechlorination is often slow and incomplete; 2) aerobic degradation is
inhibited by limited availability of oxygen in the anaerobic sediment
regions where these compounds persist. The PIs propose to complete the
anaerobic process to unflanked di- through tetrachlorinated by in situ
bioaugmention with dechlorinating microorganisms followed by application of
low current hydrolysis to provide a constant level of oxygen for the
complete degradation of the chlorinated compounds. The innovative aspects of
this appoach include the use of dechlorinating species with specific
activities to direct the anaerobic dechorination pathways, a unique process
for scaling up dehalogenating inoculum without co-release of toxic
chlorinated compounds, electrolysis of water for maintaining constant oxygen
levels during aerobic degradation and high throughput molecular assays for
monitoring microbial communities. This integrated approach will optimize
both anaerobic and aerobic processes to achieve complete in situ
detoxification of chlorinated compounds through mineralization to small
molecular weight metabolites and carbon dioxide. Implementation of a
tractable in situ detoxification process to organohalide impacted sites will
mitigate exposure to the food chain and subsequent exposure risks to the
general public.
Collaborators
Hal D. May, Ph.D. (PI) , Medical University of South Carolina
Project Team
Rayford Payne,
Ph.D.
Related Publications and Abstracts
Fagervold, S.K., H.D. May and K.R. Sowers. 2007. Microbial reductive dechlorination of Aroclor 1260 in Baltimore Harbor sediment microcosms is catalyzed by three phylotypes within the Chloroflexi. Appl. Environ. Microbiol. 73: 3009-3018.
Gregory, K. B., D. R. Bond, and D. R. Lovley. 2004. Graphite electrodes as electron donors for anaerobic respiration. Environ Microbiol 6:596-604.
Ho, S. V., P. W. Sheridan, C. J. Athmer, M. A. Heitkamp, J. M. Brackin, D. Weber, and P.H. Brodsky. 1995. Integrated in situ soil remediation technology: The Lasagna Process. Environmental Science and Technology 29:2528-2534.
Master, E. R., V. W. Lai, B. Kuipers, W. R. Cullen, and W. W. Mohn. 2002. Sequential anaerobic-aerobic treatment of soil contaminated with weathered Aroclor 1260. Environ. Sci. Technol. 36:100-3.
Funded by
