Global assessment of ocean pollution using sperm whales as an indicator species

Pollution of the ocean by persistent pollutants including metals and polybrominated diphenyl ethers (PBDE) is a global concern due to their bioaccumulative and toxic nature putting high trophic consumers at risk. The sperm whale is a sentinel of ocean health due to its wide distribution, longevity and high trophic level. The overarching aim of this study was to survey the concentrations of metals, mercury (Hg), lead (Pb), silver (Ag) and arsenic (As), the essential element, selenium (Se), and twenty-five different PBDEs worldwide in the skin of free-ranging sperm whales considering region, gender and age. From 2000-2005, >900 samples were collected in 17 regions across the globe during the Voyage of the Odyssey..;Pollutant levels were highly detectable in the samples and found as follows: Hg detectable in 99% of samples with a global mean of 2.5 ug/g ww; Pb detectable in 93% with a mean of 1.6 ug/g ww; Ag detectable in 60% with a mean of 16.9 ug/g ww; As detectable in 99% with a mean of 1.9 ug/g ww; and PBDE congeners detectable in 98% of the samples (6 congeners having detection frequencies >50%) with levels ranging from 0.9 to 44.9 ng/g ww. Considering gender and age, neither caused a significant difference in metal or PBDE concentrations except when considering As levels between gender. In the PBDE data set, BDE47 was the dominant congener, and the two methoxylated PBDEs were folds higher than the anthropogenic PBDEs.;Metal levels had hotspots: however, Se levels were folds higher suggesting a protective effect against toxicity. The Hg and Se concentrations found in the skin biopsies were used to treat cultured sperm whale skin cells, and Se protected against Hg-induced cytotoxicity and alteration of cell cycle distribution in these cells.;These data indicate the wide dispersal of metals and PBDEs in the oceans with hotspots found giving rise to concerns of possible toxicity in high trophic consumers. Se levels suggest a possible protective effect against metal toxicity. Se was found to protect against Hg toxicity in sperm whale skin cells.