SEDL / STP / STP1007-EB / STP10307S

An Approach for Development of Structure-Biodegradation Relationships of Organic Chemicals

Niemi, GJ
Associate director, Natural Resources Research Institute, University of Minnesota, Duluth, MN

Veith, GD
Director, Environmental Research Laboratory—Duluth, U.S. Environmental Protection Agency, Duluth, MN

Pages: 9    Published: Jan 1988

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Abstract

Success in the development of predictive methods for relating biodegradation rates in water to chemical structure has been elusive. We present a strategy for evaluation of biodegradability of chemicals that involves a combination of structure-biodegradation relationships (SBR) and laboratory testing arranged in a four-tier heirarchy. The first tier involves a search of a data base on biodegradation information. Each subsequent tier consists of a query of potential SBR for the chemical or an experimental laboratory test of the chemical using a tier-specific procedure. The tiered hierarchy proceeds from a data base search, the simplest and cheapest level, to a river die-away test, the most complex and expensive level.

The main purpose of the first three tiers in this strategy is to discriminate readily biodegradable from persistent chemicals. The fourth tier involves the measurement of a biodegradation rate constant under experimental conditions. If a chemical is determined to be degradable, then metabolites of the chemical are also evaluated to identify possible recalcitrant by-products. The approach (a) satisfies the critical need to develop a systematic reference data base on biodegradation endpoints for existing and new chemicals, (b) incorporates the metabolites of biodegradation into the process, and (c) provides an economical means to evaluate chemical biodegradation.