DNA ADDUCTS DETECTED IN MUSKRATS BY P-32 POSTLABELING ANALYSIS

Bottom-dwelling fish from the southern branch of the Elizabeth River, Virginia, have lesions associated with exposure to environmental contaminants (primarily polycyclic aromatic hydrocarbons [PAHs]) known to be present in that reach of the river. There is concern that other wild species such as the muskrat (Ondatra zibethicus) living in the southern branch may be adversely exposed to these contaminants. DNA adducts were detected by P-32-postlabeling methods in liver tissue of muskrats collected from the southern branch of the Elizabeth River and the Nansemond River, a nearby reference river. There was no significant difference in DNA adduct concentrations in muskrats collected from the two rivers. Ten surface sediment samples collected from the southern branch of the Elizabeth River contained concentrations of 14 PAHs ranging from 1.50 to 4,233.0 ppm dry weight (total PAHs). These concentrations were significantly greater than those detected in five surface sediment samples collected from the Nansemond River (total PAHs ranged from 0.34-0.95 ppm dry weight). This is the first known study utilizing this technique to detect DNA adducts in situ in a wild terrestrial (semiaquatic) mammalian species and the first time that muskrats have been used in P-32-postlabeling analysis.