Biodegradation is an important removal mechanism for consumer product chemicals released in large volumes to aquatic and terrestrial environments. It results in a decrease in the mass or load of chemicals mesent in the environment and is key in preventing accumulation and persistence of chemicals. ~l t h o u~h biodegradation is an important process in minimizing potentially adverse imvacts on environmental systems, it has not been traditionally considered quantitatively in environmental assessments. ~f f o r t s to use such data have principally focused on either wholly qualitative evaluations of a material's biodegradation properties (e.g., "fast" or "slow"), or rigorous quantitative models to predict exposure concentrations in particular settings. This paper outlines an alternative approach which provides a semi-quantitative analysis combining biodegradation rate data with an assessment of environmental exposure. The approach is a generic one that relates biodegradation half-lives to rates of transport and residence times in specific environmental compartments (e.g., agricultural soil, rivers). It establishes the kinetic criteria needed to make biodegradation a "practically significant" removal mechanism in a given environmental compartment. It is broadly applicable to chemicals which exhibit pseudo first order biodegradation kinetics at realistic environmental concentrations.