Persistent Organic Pollutants in Shark Blood Plasma from Estuaries along the Southeast US Coast
Bazan, Katie L.
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Persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), pose a potential threat to marine organisms because of their resistance to degradation and ability to bioaccumulate in the environment. Hydroxylated metabolites from compounds like PCBs may also disrupt the endocrine system of organisms when they are retained in the blood stream. Bonnethead (Sphyrna tiburo) and finetooth (Carcharhinus isodon) sharks inhabit coastal estuaries during the spring and summer months along the southeast US coast leaving them exposed to organic pollutants. The current study examined POPs and their hydroxylated metabolites in the blood plasma of 69 bonnethead and 30 finetooth sharks from South Carolina and Georgia estuaries. The bonnethead sharks caught in St. Simons Sound, GA contained the highest concentrations of PCBs and their hydroxylated metabolites. Specifically, 4-OH PCB 187 and 4'-OH PCB 172 were found in shark blood along with 6-OH PBDE 47. The finetooth sharks caught in Bulls Bay, SC contained roughly five times higher mean concentrations of PCBs than the bonnethead sharks caught from the same location. Bonnethead sharks caught in St. Simons Sound, GA were shown to have PCB concentrations in blood at levels comparable to those observed in bottlenose dolphins (Tursiops truncates) blood from Sarasota, FL. This indicates that more study is needed for the bonnethead sharks in the St. Simons Sound estuary and that contaminants in shark blood reflect known gradients of habitat contamination. In addition, blood can be collected from sharks in a non lethal manner which is important given that many shark stocks are being depleted and that, outside this study, there have been no systematic assessments of organic contaminant accumulation in sharks.