Transfer of contaminants from CCA-treated lumber to aquatic biota

Abstract

Green algae, Ulva lactuca (L.) and Entermorpha intestinalis (L.), were collected from bulkheads made of wood treated with chromated copper arsenate (CCA). Control algae were collected from nearby rocks. metal levels in the Ulva and Entermorpha from the CCA dock were elevated substantially over control levels. Snails, Nassarius obsoletus (Say), collected from an area from CCA-wood, were placed with control or experimental Ulva or Entermorphia. Snails feeding on experimental Ulva retracted into their shells and lay inactive on the bottom of the containers, a process that preceded death. Snails eating Entermorpha followed. By 4 wk, all the experimental snails were retracted or dead, while all control snails remained active. Thus, metals in the treated wood are taken up by attached algae, and can be toxic go grazing herbivores. Oysters, Crassostrea virginica (Gmelin), were collected from a CCA dock, a bulkhead in a canal lined with CCA wood, and rocks (reference site). Animals from the single dock had elevated Cu, and those from the bulkhead had 12 times the reference levels of Cu, and significantly elevated as. Fiddler crabs, Ucapugilator (Bosc) and U. panacea (Salmon), were collected from burrows close to or distant from CCA-treated wood structures and were analysed for metal content. Those living near CCA wood had elevated metal content, as did the sediments in which they resided. This indicates that sediments, which can absorb contaminants leached from CCA wood, are a route of exposure of benthic biota of these contaminants.