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5B b - RA: Site specific (WEP/210) Assessing the Ecological Risk of Creating Artificial Reefs from ex-Warships. Johnston, Robert1, Halkola, Heather1, William, Wild1, Gauthier, Ronald1, George, Robert , In, Christine1, Bell, Melvin2, Martore, Robert2, 1 Space and Naval Warfare Systems Center, San Diego, CA, USA2 South Carolina Department of Natural Resources, Charleston, SC, USA ABSTRACT- Inactive warships would make excellent artificial reefs in coastal waters if preliminary data suggesting that they pose no threat to human health or the environment from contamination can be confirmed. A screening level ecorisk assessment was conducted on data from artificial reefs composed of ex-warships located off the coast of South Carolina to assess the potential risk of contamination from sunken warships. Contaminants can enter the system from releases from the sunken vessel or inputs from coastal waters. The assessment endpoints for this study were the reef community and organisms that may frequent and forage on the reef. Primary exposure can occur to the reef community, which is composed of demersal fishes, epibenthic and benthic invertebrates, and primary producers and zooplankton. Indirect exposure can occur through bioaccumulation in the food chain to avian omnivores, avian piscivores, and marine mammals (food chain receptors). The conclusions were based on evidence of potential ecological harm, comparison to reference and background levels, and the reliability of the data. Tissue residue data showed that exposure to PCBs, Pb, and Cd in tissues of fish and PCBs and Pb in invertebrates were higher in samples from ex-warship reefs than reference reefs, but most of the residue data were below conservative effects levels for the reef community suggesting that there was negligible to low risk of exposure to demersal fish and reef invertebrates. For food chain receptors most data for contaminant concentrations in prey were below dietary benchmarks suggesting that there was low risk of exposure to dolphins and fish eating birds, and negligible risk of exposure to diving birds. There was high confidence of negligible to low exposure to PCBs because additional fish sampling and analysis for PCBs was conducted for the assessment. Owing to limited data available for screening, the confidence in the conclusions for the other chemicals of concern was low. Based on the finding of negligible to low ecological risk of exposure to PCBs, the risk of using ex-warships to build artificial reefs is reasonable. Key words: reef, ecorisk, PCB, bioaccumulation |
