The effects of using wood treated with chromated copper arsenate in shallow-water environments: A review

Studies published over the past several years have documented that copper, chromium, and arsenic leach from pressure-treated wood placed in estuaries, and that these toxic metals accumulate in nearby sediments and biota. We have found bioaccumulation and deleterious effects in the epibiotic (“fouling”) community, particularly in poorly flushed areas and on new wood. The epibiota showed reduced species richness, diversity, and biomass. Barnacles and encrusting bryozoa that settled on new treated wood grew more slowly than those that settled on untreated wood or plastic substrate. In laboratory studies, trophic transfer of the contaminants from epibiota to their consumers has also been demonstrated. We have also found accumulation of the treatment metals in the fine-grained fraction of nearby sediments and in the benthic infauna. Infauna also had reduced species richness and diversity in sediments adjacent to treated-wood structures. While standard toxicity tests with amphipods did not demonstrate acute toxicity of these sandy sediments, sublethal effects on development were seen in juvenile mysids. Overall, the extent and severity of effects of pressure-treated wood in an estuary depends on the amount and age of the wood and the degree of dilution by water movements.