Hexavalent Chromium May Threaten the Heath of the North Atlantic Right Whale (Eubalaena glacialis)
IAAAM 2008
John Pierce Wise1-6 Sr.; Sandra S. Wise1-3; Scott Kraus4; Fariba Shaffiey1,2; Marijke Grau1; Tania Li Chen1-3; Christopher Perkins7; W. Douglas Thompson2,3; Tongzhang Zheng8; Yawei Zhang8; Tracy Romano6; Todd O'Hara9
1Wise Laboratory of Environmental and Genetic Toxicology, 2Maine Center for Toxicology and Environmental Health, University of Southern Maine, Portland, ME, USA; 3Department of Applied Medical Sciences, University of Southern Maine; 4New England Aquarium, Edgerton Research Laboratory, Central Wharf, Boston, MA, USA; 5Ocean Alliance, Lincoln, Lincoln, MA, USA; 6Mystic Aquarium, Mystic, CT, USA; 7Center for Environmental Sciences and Engineering, University of Connecticut, Storrs, CT, USA; 8Yale University New Haven, CT, USA; 9Institute of Arctic Biology, University of Alaska, Fairbanks, AK, USA
abstract
Hexavalent chromium [Cr(VI)] is a well-established genotoxicant in humans and terrestrial mammals however, its effects are unknown and untested in marine mammals, such as the endangered North Atlantic right whale. Whales are exposed to Cr(VI) through both water and air and thus likely encounter both particulate and soluble forms of Cr(VI). In humans, the particulate form is more potent though its effects appear to be mediated through the release of soluble chromate ions. We investigated the cytotoxic and genotoxic effects of both soluble and particulate hexavalent chromium in primary North Atlantic right whale fibroblasts. Particulate Cr(VI) (lead chromate) was tested in lung and skin fibroblasts as these are the tissues likely to encounter them. Soluble Cr(VI) (sodium chromate) was tested in right whale lung, skin and testes fibroblasts as these are either sites of direct exposure or indirect after uptake. In addition, right whales are suffering reproductive problems and we had specific interest if Cr(VI) might affect cells in the reproductive system. Cytotoxicity was measured by clonogenic survival assay and genotoxicity was measured as production of chromosome aberrations. Both forms of Cr(VI) induced concentration-dependent increases in cytotoxicity and genotoxicity in all cell types indicating that Cr(VI) is toxic to whale cells. We then assessed whether right whales were exposed to chromium by measuring tissue chromium levels in skin biopsies of healthy free-ranging whales in the Bay of Fundy. The skin biopsy data indicate that the whales are indeed exposed to chromium with a range of 4.9-10 ug Cr/g tissue with a mean of 7.1 ug/g. These levels are remarkably high and are comparable to levels only seen in humans that have suffered Cr-induced lung cancer. Thus, this study suggests that Cr(VI) may be a concern for the health of the North Atlantic right whales. Considering chromium chemistry, whale physiology and atmospheric chromium levels, these data further suggest that inhalation may be an important route of exposure for whales. This work was supported by Grant number NA03NMF4720478 from the United States Department of Commerce, National Oceanic and Atmospheric Administration (J.P.W.) and the Maine Center for Toxicology and Environmental Health.