Structural properties of organic chemicals as predictors of biodegradation and microbial toxicity in soils

The evaluation of a chemical's persistence in soil is a major source of uncertainty in environmental risk assessments. Structure-activity relationships (SARs) may provide a useful estimation tool for biodegradability and toxicity of chemicals in soils; however, experiments must be designed to minimize or account for competing loss processes. Biodegradation and toxicity SARs have been described for groups of structurally related molecules in soils, but multiple SARs will undoubtedly be required to estimate properties from large data sets that include dissimilar compounds. These studies provide evidence that the SAR approach has applicability to environmental risk assessments for chemicals in soils, despite important limitations to our ability to extrapolate SARs from one homologous series of chemicals to another.