The transport and effects of 14C-labeled wood preservatives (creosote with labeled phenanthrene or acenaphthene, pentachlorophenol, and bis(tri-n-butyltin)oxide) impregnated in wood posts were examined in a terrestrial microcosm chamber (TMC-II) in comparison to a reference compound, the insecticide dieldrin. The TMC-II contained a Willamette Valley topsoil, ryegrass, invertebrates, and a gravid gray-tailed vole (Microtus canicaudus). Approximately 2.5 months after introduction of the posts, 95% of the chemicals remained in the post, 95% of the chemicals remained in the posts. Of the material released into the ecosystem, most remained in the upper soil layer immediately surrounding the posts. Concentrations in plants ranged from 0.7 ppm for dieldrin to 8.8 ppm for phenanthrene. Residue accumulation by the invertebrates was highly variable. Of the chemicals tested, creosote accumulated in the vole to the greatest extent (e.g., whole body concentrations of 7.2 and 37.0 ppm for phenanthrene and acenaphthene, respectively. Only dieldrin exhibited any acute toxic effects (e.g., cricket survival).