ABSTRACT
Chlorinated solvents are the most prevalent contaminants at Superfund sites in the United States according to the USEPA and the National Research Council. These contaminants, comprised of carbon, hydrogen and chlorine were previously thought to be recalcitrant in the ambient environment, particularly in groundwater. These contaminants are sparingly soluble in water, readily sorb to organic rich sediments, and tend to form stable subsurface "pools" or "DNAPL source" areas which lead to their aforementioned reputation. More recently, however, a body of scientific evidence has been generated that demonstrates such contaminants do, in fact, attenuate in the subsurface environment via physical-chemical and biological mechanisms. In particular, the natural biological degradation of chlorinated solvents in groundwater has been a fertile area for research in an attempt to expand our fundamental knowledge of the processes that can effectuate such attenuating transformations.
