This seminar is the fourth in a series sponsored by the NIEHS Superfund Basic Research Program to present current research on DNAPLs contaminated sites. Dr. Jim Field, of the University of Arizona, will summarize a comprehensive literature review on the microbial degradation of chlorinated solvents. Chlorinated solvents such as chlorinated ethenes, ethanes and methanes are important priority pollutants of groundwater. Diverse strategies are utilized by microorganisms in the degradation of organochlorine compounds ranging from reductive dehalogenation, hydrolytic to oxygenolytic release of chloride. To understand how microorganisms gain energy and benefit from biodegradation of chlorinated solvents, one must consider biodegradation as a redox reaction in which an electron donor becomes oxidized at the expense of an electron acceptor. In addition to the discussion of bioremediation processes, Dr. Lee Newman of the University of South Carolina, will discuss advances in phytoremediation techniques for important toxicants at hazardous waste sites. Dr. Newman has successfully screened a number of plants, evergreen and deciduous, trees and herbaceous plants, and has found that the metabolism of trichloroethylene (TCE) occurs in all plants tested. This has the potential to have a significant impact on those sites where both remediation and concurrent restoration is desired. |