The transport and metabolism of 14C-labeled herbicides (simazine, bromacil, trifluralin, and 2,4,5-T) applied as a foliar spray (0.28 kg/ha) was examined in a terrestrial microcosm chamber (TMC). These chemicals were compared to a reference compound, the insecticide dieldrin. The TMC contained a synthetic soil medium, Douglas fir and red alder seedlings, rye grass, numerous invertebrates, and a gravid gray-tailed vole (Microtus canicaudus). By 20 days posttreatment, total soil residues (parent and metabolites and bound residues) averaged 0.14 ppm for all chemicals. Except for dieldrin little extractable parent material was detected for any of the chemicals in the soil. Concentrations of 14C material in the rye grass shoots ranged from an average of 2.5 ppm for 2,4,5-T to 16.8 ppm for simazine. 2,4,5-T and trifluralin were more rapidly degraded than the other chemicals with 2,4,5-T present primarily as extractable metabolites. 14C materials of dieldrin was accumulated to a much greater extent than any of the herbicides in the invertebrates. While concentrations of all chemicals in the vole were low, 14C material from dieldrin and simazine was present at levels approximately twice those of the other chemicals. None of the chemicals could be detected in the ground water.