For the past several decades, it has been observed that various marine mammal populations, including those of harbor seals (Phoca vitulina), northern fur seals (Callorhinus ursinus), stellar sea lions (Eumetopias jubatus) and northern sea otters (Enhydra lutris), have undergone significant 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 between 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. A relationship between the accumulations of metals in keratinized (tissues composed of keratin such as hair, fur and whiskers) versus non-keratinized body tissues showed that both tissue types appeared to have the greatest concentrations of chromium and zinc. There were also significant concentration differences among species for Cd (p=0.0000445), Cu (p=0.0367), Pb (p=0.0844), V (p=0.00653) and Zn(p=0.00543) which may be a representation of how their diets differ. In addition, the concentrations of essential metals (Cu, Zn, Fe, Ni) were significantly greater (p=0.0281) than concentrations of non-essential metals (As, Cd, Pb, Hg). Since most current literature reports heavy metal concentrations for non-keratinized body tissues which typically requires deceased animals or invasive techniques on living animals, use of keratinized tissues may provide a less intrusive method to determine the effects of heavy metal contaminants on marine mammals. The information obtained during this study can also be used to determine the potential role of heavy metals in marine mammal population dynamics.

Multi-decadal assessment of heavy metals in body tissue and vibrissae of select North Pacific marine mammals

255th National Meeting (2018)

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