Research Product

Green algae, Ulva lactuca (L.) and Enteromorpha 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 Enteromorpha from the CCA dock were elevated substantially over control levels. Snails, Nassarius obsoletus (Say), collected from an area distant from CCA-wood, were placed with control or experimental Ulva or Enteromorpha. 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 Enteromorpha 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 to 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, Uca pugilator (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 to these contaminants.