COMPARATIVE-STUDY OF CONTAMINANTS IN THE MUDPUPPY (AMPHIBIA) AND THE COMMON SNAPPING TURTLE (REPTILIA), ST-LAWRENCE-RIVER, CANADA

Levels of organochlorine pesticides, polychlorinated biphenyl (PCB) co ngeners and mercury were measured in mudpuppy bodies, livers and gonad s and in snapping turtle eggs to determine how the composition and con centration of these bioaccumulated contaminants differ between the two species. Furthermore, the geographic variation in contamination patte rns were examined between the highly polluted St. Lawrence River and t he much less polluted Ottawa River, Canada. Principal component analys is performed with 69 tissue samples (30 samples of mudpuppy tissues an d 39 turtle egg clutches) indicated distinct contamination patterns in the two species for PCB congeners; PCB congener composition in mud-pu ppies resembled the pattern reported for fish while the turtle pattern was more akin to the bird pattern. This could be related to the metab olic capacity of each species. The organochlorine pesticide contaminat ion profile was also species-specific although highly variable among l ocations. Contamination profiles were similar for mudpuppy gonads and carcasses but lipid-weight basis concentrations were often a little hi gher in gonads. In both species, geographic variations in contaminatio n patterns were noticeable and significant differences in contaminatio n levels were detected between Ottawa River and St. Lawrence River sam ples. However, in both species, concentrations varied considerably wit hin a single location. Sources of variability are discussed although t he basic life history of these species in the St. Lawrence River syste m is relatively unknown.