title: Global mercury and selenium concentrations in skin from free-ranging sperm whales (Physeter macrocephalus).
abstract: Pollution of the ocean by mercury (Hg) is a global concern. Hg persists, bioaccumulates and is toxic putting high trophic consumers at risk. The sperm whale (Physeter macrocephalus), is a sentinel of ocean health due to its wide distribution, longevity and high trophic level. Our aim was to survey Hg concentrations worldwide in the skin of free-ranging sperm whales considering region, gender and age. Samples were collected from 343 whales in 17 regions during the voyage of the research vessel, Odyssey, between 1999 and 2005. Skin was analyzed for total Hg and detected in all but three samples with a global mean of 2.5±0.1 μg g(-1) ranging from 0.1 to 16.0 μg g(-1). The Mediterranean Sea had the highest regional mean with 6.1 μg g(-1) followed by Australia with 3.5 μg g(-1). Considering gender, females and males did not have significantly different global Hg concentrations. The variation among regions for females was significantly different with highest levels in the Mediterranean and lowest in Sri Lanka; however, males were not significantly different among regions. Considering age in males, adults and subadults did not have significantly different Hg concentrations, and were not significantly different among regions. The toxic effects of these Hg concentrations are uncertain. Selenium (Se), an essential element, antagonizes Hg at equimolar amounts. We measured total Se concentrations and found detectable levels in all samples with a global mean of 33.1±1.1 μg g(-1) ranging from 2.5 to 179 μg g(-1). Se concentrations were found to be several fold higher than Hg concentrations with the average Se:Hg molar ratio being 59:1 and no correlation between the two elements. It is possible Hg is being detoxified in the skin by another mechanism. These data provide the first global analysis of Hg and Se concentrations in a free-ranging cetacean.
authors: Wise Laboratory of Environmental and Genetic Toxicology, University of Southern Maine, P.O. Box 9300, 96 Falmouth St., Portland, ME 04104, USA.
authors: Laura C
authors: LC
authors: Savery
authors: David C
authors: DC
authors: Evers
authors: Sandra S
authors: SS
authors: Wise
authors: Carolyne
authors: C
authors: Falank
authors: James
authors: J
authors: Wise
authors: Christy
authors: C
authors: Gianios
authors: Iain
authors: I
authors: Kerr
authors: Roger
authors: R
authors: Payne
authors: W Douglas
authors: WD
authors: Thompson
authors: Christopher
authors: C
authors: Perkins
authors: Tongzhang
authors: T
authors: Zheng
authors: Cairong
authors: C
authors: Zhu
authors: Lucille
authors: L
authors: Benedict
authors: John Pierce
authors: JP
authors: Wise
mesh_terms: D000818:Animals; D004784:Environmental Monitoring / Q000379:methods*; D005260:Female; D008297:Male; D008628:Mercury / Q000032:analysis* / Q000493:pharmacokinetics; D009792:Oceans and Seas; D012643:Selenium / Q000032:analysis* / Q000493:pharmacokinetics; D012867:Skin / Q000737:chemistry / Q000378:metabolism*; D013054:Spectrophotometry, Atomic; D050661:Sperm Whale / Q000254:growth & development / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000493:pharmacokinetics
chemical_list: D014874:Water Pollutants, Chemical; D008628:Mercury; D012643:Selenium