Sources of methylmercury, perfluoroalkyl substances, and polychlorinated biphenyls to ringed seal food webs of Lake Melville, Northern Labrador

The objectives of this project are: 1. Determine levels and trends of contaminants, including methylmercury, PFASs and PCBs, in Lake Melville ringed seals, which are the top predator and an important source of food to people living along the shoreline of Lake Melville, Northern Labrador.2. Differentiate and identify the relative importance among global versus local and terrestrial versus marine sources of methylmercury, perfluoroalkyl substances (or perfluorinated alkyl substance, PFASs) and polychlorinated biphenyls (PCBs) to ringed seals using combined analyses of carbon, nitrogen, mercury stable isotopes, and PFASs and PCBs congeners in ringed seal tissues. 3. Examine the bioaccumulation and biomagnification of PFASs in the Lake Melville ringed seal food web by analyzing water, plankton, fish, and other food web samples. 4. Investigate the rate of plastics ingestion in ringed seal as well as the polymer signatures of the plastics to increase knowledge about possible sources of ingested plastics. 5. Assess the health of ringed seals as a function of contaminant exposure (mercury, PFAS, PCBs) in Lake Melville using cellular and molecular tools including targeted gene expression analysis and metabolite profiling (i.e., screening a large suite of low-molecular weight metabolites e.g., amino acids, fatty acids, amines, and sugars).6. Communicate results to the Nunatsiavut Government and each participating community on a timely basis.