Comparative study of contaminants in the mudpuppy (amphibia) and the common snapping turtle (reptilia), St. Lawrence River, Canada

Abstract

Levels of organochlorine pesticides, polychlorinated biphenyl (PCB) congeners and mercury were measured in mudpuppy bodies, livers and gonads and in snapping turtle eggs to determine how the composition and concentration of these bioaccumulated contaminants differ between the two species. Furthermore, the geographic variation in contamination patterns were examined between the highly polluted St. Lawrence River and the much less polluted Ottawa River, Canada. Principal component analysis performed with 69 tissue samples (30 samples of mudpuppy tissues and 39 turtle egg clutches) indicated distinct contamination patterns in the two species for PCB congeners; PCB congener composition in mudpuppies resembled the pattern reported for fish while the turtle pattern was more akin to the bird pattern. This could be related to the metabolic capacity of each species. The organochlorine pesticide contamination profile was also species-specific although highly variable among locations. Contamination profiles were similar for mudpuppy gonads and carcasses but lipidweight basis concentrations were often a little higher in gonads. In both species, geographic variations in contamination patterns were noticeable and significant differences in contamination levels were detected between Ottawa River and St. Lawrence River samples. However, in both species, concentrations varied considerably within a single location. Sources of variability are discussed although the basic life history of these species in the St. Lawrence River system is relatively unknown.