Brominated and chlorinated organic contaminants in North American Native mussels from remote watersheds of Michigan.

L.J. Begnoche¹, S.J. Nichols¹, R.T. Quintal¹, J.P. Hickey¹, J.D. Allen¹, G.W. Kennedy¹, M.G. Black¹, and S.M. Chernyak². ¹USGS-Great Lakes Science Center, Ann Arbor, MI, USA, 48105, ²University of Michigan, Environmental Health Sciences, Ann Arbor, MI, USA, 48109

Due to atmospheric transport, trace levels of organic contaminants have been found in four species of North American native mussels (Pyganodon cataracta, Pyganodon grandis, Lampsilis siliquoidea, and Elliptio dilatata) from three remote National Parks in Michigan: Isle Royale, Sleeping Bear Dunes and Pictured Rocks National Lakeshore. Determinations were made for contaminant residues of 80 PCB congeners and Total PCBs, 22 pesticides, and four polybrominated diphenyl ethers (PBDE) in mussels collected from these parks during 1999 and 2000. PBDEs, emergent chemicals of concern, were present at trace levels in mussels from 22 out of 24 sites. Average total PBDEs were 0.35 ng/g at Sleeping Bear Dunes, 0.19 ng/g at Pictured Rocks, and 0.18ng/g at Isle Royale. Trace levels of PCBs were present, with varied congener patterns, at all locations. p,p’-DDE was found in mussels from Sleeping Bear Dunes and Pictured Rocks but not in Isle Royale mussels. Toxaphene was present (< 5 ng/g) in a few samples from Isle Royale and Sleeping Bear Dunes. High densities and populations of mussels in some of these waters pose serious threats to ecosystems should a die-off occur and sequestered contaminants are re-released into the environment.