Multi-Decadal Assessment of Heavy Metals in Body Tissue and Vibrissae of Select North Pacific Marine Mammals

Multi-Decadal Assessment of Heavy Metals in Body Tissue and Vibrissae of Select North Pacific Marine Mammals

Since the 1970s, marine mammal populations, including harbor seals (Phoca vitulina), northern fur seals (Callorhinus ursinus), Steller sea lions (Eumetopias jubatus) and northern sea otters (Enhydra lutris) in the northwest Pacific Ocean have undergone significant population changes. The effects of environmental contamination on marine mammal health are of concern related to population dynamics, yet limited information is available on heavy metal concentrations for these species. Archived vibrissae (whiskers) and body tissues from these four species were collected from the Bering Sea and throughout the Gulf of Alaska from 1990 to 2013. The concentrations of heavy metals (As, Cd, Cr, Co, Cu, Hg, Mn, Ni, Pb, Se, V, Zn) within the various body tissues and vibrissae of these four species were determined via atomic absorption spectrophotometry. Among all tissues, Zn and Cr frequently had the greatest concentrations. There were also significant concentration differences among vibrissae from all species for Cd (p<0.0001), Cu (p=0.0367), Pb (p=0.0844), V (p=0.0065) and Zn (p=0.0054), yet no significant metal concentration differences were observed for the body tissues of harbor seals and Steller sea lions. Heavy metal analysis of vibrissae may provide a less invasive procedure to determine total body metal concentration through comparison of keratinized and non-keratinized tissues. Data from this study contribute to a larger baseline study of heavy metals in marine mammals.