Contaminant residue levels in arctic wolves (Canis lupus) from the Yukon Territory, Canada.

Kidney, liver and bone samples were taken from 19 wolves (Canis lupus) collected from two locations in the Yukon Territory. Liver samples pooled by age and sex were analyzed for 22 organochlorine pesticides and 101 PCB congeners. Individual kidney and liver samples were analyzed for arsenic, cadmium, copper, lead, total mercury, selenium and zinc. Thirteen individual bone samples were analyzed for lead. While most organochlorines were not present at detectable levels in wolf liver, some chlorobenzenes, dieldrin and sigma PCB were present at low levels. PCB congeners 149, 153, 170/190, 180 and 187/182 made up 86% of the total PCBs measured in wolf liver. The hexa- and heptachlorobiphenyls dominated the pattern in wolf liver, while congeners containing less than five chlorine atoms were not detected. The pattern of chlorobenzene and PCB homologues found in wolf liver are more similar to those found in marten (Martes americana) and other carnivores than caribou (Rangifer tarandus), perhaps reflecting similarities in food habits and metabolic capacities. With the exception of cadmium, average element concentrations in all wolf tissues are similar to those found in other arctic carnivores. Cadmium concentrations in wolf liver and kidney were somewhat higher in Yukon wolves than other arctic wolves. This may reflect high cadmium concentrations found in livers and kidneys of moose and some caribou herds in the Yukon. Renal arsenic and bone lead decreased significantly with age in wolves, while renal mercury increased with age. Because the ranges seen are relatively small, and all values are within the range normally seen in wildlife, it is difficult to determine the biological significance of these relationships. Contaminant levels in Yukon wolves are generally low and are similar to those found in other arctic terrestrial carnivores. They do not approach levels that are known to potentially cause adverse effects in animals. Contaminant concentrations found in this study should be considered baseline levels.