QUANTITATIVE APPLICATION OF BIODEGRADATION DATA TO ENVIRONMENTAL RISKAND EXPOSURE ASSESSMENTS

Biodegradation is an important removal mechanism for natural and synth etic organic chemicals released to aquatic, benthic, and terrestrial e cosystems. It results in a decrease in the overall mass or load of che micals present in the environment and is key in preventing the accumul ation and persistence of chemicals in specific environmental compartme nts. Although biodegradation is an important process for minimizing po tential adverse impacts on environmental systems, it has not been trad itionally considered in a quantitative fashion in environmental risk a ssessments. This article outlines an approach and provides simple kine tic criteria for incorporating biodegradation rate data into environme ntal exposure and risk assessments. The approach is a generic one that relates biodegradation half-lives to chemical residence times in spec ific environmental compartments. It is broadly applicable to any organ ic chemical in a range of environmental compartments and has potential use as a technical and regulatory tool to better quantify environment al exposure and risk.