Abstract

Contaminants in the marine environment pose significant health risks for marine mammals. Little is known about the direct effects of marine contaminants on marine mammals. We have initiated investigations of how several classes of contaminants affect the Northern Atlantic right whale. It is particularly important to understand the effects of contaminants on the right whale as their population has been reduced to a few hundred individuals and is not increasing. A potential explanation for low abundance and poor reproductive performance is the presence of environmental contaminants. Right whales are exposed to a variety of contaminants including polycyclic aromatic hydrocarbons (PAHs), metals, anti-fouling agents, anticorrosives, and radionuclides in their environment and diet. We evaluated the cytotoxic and genotoxic effects of mercury (HgCl2), tributyltin (TBT) and hexavalent chromium (Cr(VI)) in various cell lines derived from a stranded north Atlantic right whale including skin, lung and testes. Cells originating from lung were more resistant to Cr than skin and testes which had very similar cytotoxic responses. Specifically, 24 h exposure to Cr(VI) induced 88, 74, 52, 28 and 0 percent relative survival in lung cells at concentrations of 1, 2.5, 5, 10 and 25 uM; testes had a relative survival of 84, 86, 22, 2, and 0 percent and skin had a relative survival of 77, 58, 38, 6, and 0 percent at the same concentrations. Mercury did not induce a toxic effect in any of the cell lines at the concentrations tested, (1, 2.5, 5, 10 and 25 uM). TBT was the most toxic chemical tested in all cells; by 2 uM there was no survival in any cell lines. When we looked at the genotoxic effects of these chemicals we found that the cells had different sensitivities. For example, Cr(VI) damaged only 7 percent of skin metaphase cells when treated with 5 uM, however the same concentration damaged 27 percent of lung metaphase cells and 40 percent of testes metaphase cells. Mercury induced only a small percentage of damage; in both lung and skin metaphase cells (50 uM damaged 14 percent of metaphases). Testes cells were not yet tested. TBT did not induce any chromosome damage but did induce complete cell cycle arrest by 1 uM. Further work will include investigating the effects of PAHs and flame retardants. We will also begin to look at individual differences in response to genetic damage from these contaminants. This work was supported by NOAA grant NA03NMF4720478. Tissues were obtained under NMFS Permit No.1008-1637-00.