The Impact of Acute and Prolonged Particulate Hexavalent Chromium Exposure in Fin Whale and Humpback Whale Cells.

Supervisor: John Pierce Wise (University of Louisville).
Humans and marine mammals are highly exposed to metal pollutants. To assess their toxicity, One Health approach offers an opportunity to study their interconnectedness between these two biological groups and the environmental health. This study focuses on zinc chromate as a model for particulate hexavalent chromium exposure and two different marine mammal species as sentinel species. Fin whales (Balaenoptera physalus) and humpback whales (Megaptera novaeangliae) are long lived animals that may, as other whales studied previously, accumulate high chromium levels on their skin tissues, suggesting they are highly exposed to chromium. Among the notorious effects of chromium, it is known to induce lung cancer and reproductive failure in human and laboratory animals. Marine mammals are good model species for chromium assessment because they are overexposed due to their deep diving behavior, which prolongs the exposure time of chromium in the lung tissue. Therefore, the aim of this study it to analyze the cytotoxic and genotoxic effects of both prolonged and acute exposure of chromium in cells from these two species. Both species showed a cytotoxic and genotoxic response to chromium in a concentration dependent manner. Some statistically significant (p<0.05) differences were observed between sexes, time point, concentrations and species. Overall, both species showed a resistance to chromium toxicity comparing to previously published human results, which suggests marine mammals may have developed cellular mechanisms to counterbalance chromium induced toxicity. In the future, assessing some of the cellular mechanisms activated after the exposure, such as, DNA repair pathways, could give some insights on both the mechanisms of chromium toxicity and the development of therapeutic drugs.