Elise Adams is a master’s student, (Northern Arizona University) who did a two-week research project on PCB levels in mainly mussel and fish samples over 30 sites in Unalaska last summer. This summer, she shared some alarming results with us. Though most of the samples showed PCB levels were safe, lower than the action level recommended by EPA, some showed significantly higher amounts. This specific site (T dock by Delta Western) had the highest reading of PCB in a mussel sample, 0.0629 parts per million of heavy PCB. Regarding EPA, the PCB concentrations in blue mussels collected from this site exceed the safe consumption limits of 1-16 meals/month for non-cancer endpoints and 1-4 meals/month for cancer-related health endpoints.
The dock area is primarily industrial. Many people fish on the island for subsistence but, mussels generally aren't harvested by locals. Elise's research was based on fish and blue mussels because it was the two most common species to test from the water. This specific mussel sample was picked up from the beach by the dock. The background story is that there was a big spill of PCBs during WWII when the island was bombed. There was a bomb dropped on an electric transformer (which contained PCBs) close to this dock area, which now is a storage warehouse for Alaska Ship Supply. Even though blue mussels may not be harvested from the dock beach, there is concern that PCBs may affect the aquatic ecosystem so important to the subsistence lifestyle of the locals.
PCBs are a broad category of manufactured chemicals previously used in the United States in electrical and hydraulic equipment, plasticizers in paints, plastics, and rubber products, among others. PCBs are “persistent” meaning they remain in the environment, cycling between air, water, soil, and bioaccumulating in some wildlife. The manufacture and use of PCBs in the United States was banned in 1977. When consumed in elevated levels, PCBs can affect the people's health.
Species of bivalves, such as oysters, clams, mussels, ad scallops, accumulate environmental contaminants by filter-feeding from the water. Bivalve species are often used for monitoring because while their distribution is wide, they do not travel, and can be used to evaluate local water quality. To understand the levels of PCB present in other species in the same local habitat, those species would have to be tested. In Alaska, the Alaska Department of Environmental Conservation and the Alaska Department of Health and Social Services monitor contaminant levels in both fish and people. Between 2001 and 2014, 24 species of fish were tested for contaminants. The species that were found to have levels above the EPA Human Health Screening Value were lake trout, spiny dogfish, sablefish, sleeper shark, and the salmon shark.
Listed in the attached documents are fish consumption guidelines developed by the Alaska Division of Public Health, Section of Epidemiology. Fish consumption has many health and cultural benefits, but to protect the health of children and developing fetuses, the Section of Epidemiology recommends that "pregnant women, women of childbearing age who may become pregnant, nursing mothers, and children (defined as age <18 years) limit their consumption of lake trout, medium to large halibut (40–80 pounds), and medium-sized lingcod (35-40 inches length) to sixteen meals per month. These sensitive groups are advised to limit longnose skate, large halibut (80–140 pounds), and large lingcod (40–45 inches length) to twelve meals per month, and limit yelloweye rockfish, and very large halibut (140–220 pounds) to no more than eight meals per month. Pregnant women, women of childbearing age who may become pregnant, nursing mothers, and children aged <18 years are advised to limit their consumption of salmon shark, spiny dogfish, very large lingcod (≥45 inches), and extra-large halibut (>220 pounds) to no more than four meals per month." *Erica Lujan*
This observation has been shared with the Alaska Department of Environmental Conservation.
Sources:
- EPA- Polychlorinated Biphenyls (PCBs)
- Ambrosio, L., Russo, R., Salzano, A. M., Serpe, F. P., Ariano, A., De Tommasi, N., . . . Severino, L. (2018). Accumulation of polychlorinated biphenyls in mussels: A proteomic study. Journal of Food Protection, 81(2), 316-324.
- Hamade, Ali K., (2014) Fish Consumption Advice for Alaskas A Risk Management Strategy to Optomize the Public's Health. State of Alaska, Department of Health and Social Services, Division of Public Health, Section of Epidemiology.
Blue mussel
