A One Environmental Health Perspective: Insight into the Cytotoxic and Genotoxic Effects of Hexavalent Chromium in Human, Aquatic Reptile and Aquatic Mammal Skin Cells
Hexavalent Cr(VI) is a human carcinogen and a global marine pollutant. The health impacts of Cr(VI) in marine animals is uncertain. We compared the cytotoxic and genotoxic effects of Cr(VI) in human cells with hawksbill sea turtle (Eretmochelys imbricata), American alligator (Alligator mississippiensis), and fin whale (Balaenoptera physalus) cells. Cr(VI) was cytotoxic and clastogenic to all 4 species. Human cells were most sensitive to the cytotoxic effects of Cr(VI) and whale cells were most resistant. For example, 2.5 µM sodium chromate induced 72, 60, 24, and 4% relative survival, and 1 µg/cm2 lead chromate induced 68, 54, and 10% relative survival in whale, alligator, turtle, and human cells, respectively. Human cells were also the most sensitive and whale cells the most resistant to Cr(VI)-induced genotoxicity. For example, 2.5 µM sodium chromate induced 11 aberrations in 100 whale cell metaphases compared to 26, 35, and 64 aberrations in 100 metaphases in turtle, alligator, and human cells, respectively. Differences in intracellular Cr levels explained the variations in cytotoxicity between cell lines. However, when these differences were adjusted for, alligator cells were the most sensitive to the genotoxic effects Cr(VI). Altogether the data suggest Cr(VI) is a concern for marine animals and that aquatic animals may be good sentinels for the genotoxic impacts of Cr contaminated ecosystems. The data also suggests whale cells may have more efficient cellular mechanisms to protect against chromium induced genotoxicity.
The authors would like to acknowledge the late Lou Guillette, Jr. for his dedication to investigating the interrelationship between the marine environment and human health. We would like to thank Greer Chapman, Matt Guillette, John W. Wise Jr., and Christy Gianios Jr., for technical support. This work was supported by the Pacific Life Foundation Marine Mammal Research Fund at the Ocean Foundation, National Institute of Environmental Health Services grant ES016893 (J.P.W.); National Oceanic and Atmospheric Administration grant NA03NMF4720478 (J.P.W.); the United States Environmental Protection Agency Greater Research Opportunities Fellowship Assistance Agreement No. MA-91739301-0 and the Curtis and Edith Munson Foundation (J.P.W.). Marine mammal and sea turtle cell line development and use by the Wise Laboratory for Environmental and Genetic Toxicology is performed under National Marine Fisheries Service Permit #16305. The content is solely the responsibility of the presenters and does not necessarily represent the official views of the National Institute of Environmental Health Sciences or the National Institutes of Health.
* Presenting author