Toxic Contaminants in Dungeness crab (Metacarcinus magister) and Spot Prawn (Pandalus platyceros) from Puget Sound, Washington, USA

In 2011-2012 the Washington Department of Fish and Wildlife (WDFW) conducted a Puget Sound-wide assessment of toxic contaminants in Dungeness crab (Metacarcinus magister) and spot prawn (Pandalus platyceros); its purpose was to (a) evaluate the geographic extent and magnitude of toxic contaminants in these two crustacean species in Puget Sound and (b) to provide contaminant data to Washington State Department of Health (DOH) to conduct a human health risk assessment. The study was designed to sample animals typically taken in fisheries, across areas typically fished, and using typical sport-fishery gear. In addition, within each species, we sought to hold potentially confounding biological covariates (such as size and sex) constant across sampling areas. Data summaries herein are focused on a comparison of contaminant concentrations in crustacean tissues across sampling areas in Puget Sound. Evaluation of the significance of contaminant levels on human health will be conducted by DOH. Raw data are included in Appendix C of this document.

Two hundred forty Dungeness crab specimens were collected at 54 stations, from which we generated 56 crab muscle and 19 crab hepatopancreas composites. Seven hundred seventy-seven spot prawn specimens were collected at 42 stations, from which we generated 43 spot prawn muscle and 16 spot prawn head-tissue composites. Study specimens were collected with the help of various tribal test fishery biologists, WDFW crab and prawn test fishery staff, and the WDFW Puget Sound Ecosystem Monitoring Program (PSEMP) team. Sampling occurred in nine WDFW Marine Areas (fishery management areas for marine recreational fishing per WAC 220-56-185) and three urbanized embayments, which were sub-divisions of Marine Areas. The WDFW Marine Areas (MAs) were MA 6, 7, 8.1, 8.2, 9, 10, 11, 12, and 13, with three urban embayments in in MA 10 (Elliott Bay and Sinclair Inlet) and MA 11 (Commencement Bay). Persistent organic pollutants (POPs) including polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides and six metals (mercury, arsenic, cadmium, copper, lead and zinc) were analyzed in crab and prawn tissues.

Of the POPs, PCBs were detected most frequently in Dungeness crab and spot prawn and were highest in specimens taken from urban areas. DDTs and PAHs in both species, and PBDEs in crab, were detected frequently at lower concentrations, with highest levels in samples from urban areas. PBDEs were rarely detected in spot prawn from any area. Mercury, arsenic, copper and zinc were the most frequently detected metals in Dungeness crab, while those metals plus cadmium were most frequently detected in spot prawn. Unlike the POPs, metal concentrations in Dungeness crab and spot prawn muscle were relatively evenly distributed throughout all Marine Areas and urban embayments of Puget Sound. Mercury was the only metal that occurred in significantly greater levels in urban than non-urban areas.

With the exception of a few metals, all contaminant concentrations in the hepatopancreas of Dungeness crab and head tissue of spot prawn were greater (as much as 36 times) than their corresponding muscle tissue. In addition, nearly all of the analytes detected in the hepatopancreas of Dungeness crab and the head tissue of spot prawn were positively correlated with their muscle concentrations. Because variability in these relationships was moderate to high, our confidence in predicting contaminant concentrations in the head of spot prawn or the hepatopancreas of Dungeness crab based on their muscle tissue ranges widely.