A study was conducted to determine the feasibility of devising a chemical assay to predict the bioavailability of organic compounds that become sequestered in soil. The recovery of atrazine and phenanthrene freshly added to soil varied appreciably among individual solvents, but the quantity extracted by each solvent declined as the test compounds persisted in soil. The percentage recovered by some extractants approximated either the percentage uptake by earthworms or bacterial degradation. Recovery by one extractant predicted bioavailability to both organisms. The data suggest that it is feasible to predict bioavailability of persistent organic compounds in soil by chemical procedures.