Project Summary (2000-2006)

Biological and chemical remediation technologies offer the advantage of partial or complete degradation of Superfund chemicals rather than simple transfer from one compartment to another. The ultimate goal of these technologies is the complete conversion of toxic chemicals to their mineral end products such as CO2, Cl- and H2O. Frequently, however, intermediates are produced from the partial transformation of Superfund chemicals. These intermediates may have sufficient stabilities so that they exist in the environment over the time frames relevant to risk assessors and regulators. Traditionally, remediation is vewed from the standpoint of parent compound disappearance, and the assumption is that this equates to a cleaner and safer environment. However, an accurate assessment of the efficacy of remedial technologies requires knowledge of the biologic activities of stable intermediates produced during remediation, both as individual compounds and as mixtures representing their environmental occurrence. Project investigators are generating and evaluating remediation products of PCB and PAH mixtures and of halogenated solvents and metals. Results provide the basis for a more accurate assessment of remediation technologies and how to improve them, as well as a more complete understanding of the mechanisms by which Superfund chemicals and their remediation products exert their biological actions.