Organochlorine pesticide, polychlorinated biphenyl and heavy metal concentrations in wolves (Canis lupus L. 1758) from north-west Russia.

The wolf Canis lupus is a major terrestrial predator in eastern Europe and, as a top carnivore, may be exposed to high concentrations of contaminants that are readily transferred through the food chain. Despite this, there are few published data on pollutant and pesticide levels in wolves. This study utilised tissues from animals legally killed by hunters for other reasons (animals were not killed for the purposes of this study) to carry out the only detailed investigation of contaminants in wolves in Europe and the first in animals from Eastern Europe. The livers of 58 wolves from the Tver and Smoliensk regions of northwest Russia (54 degrees N 31 degrees E to 57 degrees N 35 degrees E) were analysed for seven organochlorine pesticides, 24 PCB congeners, Aroclor 1254-matched summed PCBs (sigmaPCBs), total mercury, cadmium and lead. Cadmium, most of the organochlorine pesticides and many PCB congeners were not detectable in any of the wolves. Hexachlorobenzene, alpha-HCH, pp'DDE, PCB congeners 118, 138, 149 and 156 and lead were detected in up to 6% of livers. Dieldrin, PCB congeners 153, 170 and 180, sigmaPCBs and mercury were detected more frequently. Contaminant levels were generally low; maximum wet weight concentrations of any of the organochlorine pesticides, sigmaPCBs and mercury were less than 0.1, 1 and 0.25 microg g(-1), respectively. PCB congeners 153, 170 and 180 accounted for 41% of the sigmaPCBs. Dieldrin, sigmaPCBs and mercury concentrations did not vary significantly between males and females nor between adult and juvenile (< 12 months old) wolves apart from the sigmaPCB concentration, which was on average five times higher in adults than juveniles. Liver residues were generally below the level normally associated with adverse effects except for lead levels which exceeded the critical 5 microg g(-1) dry wt. concentration in three of the 58 animals examined.

Hunting practices increase the prevalence of Trichinella infection in wolves from European Russia.

From 1998 to 2000, 184 animals (82 wolves, 29 red foxes, 55 mustelids, 5 raccoon dogs, and 13 domestic dogs), mainly shot by hunters in the Tvier and Smoliensk regions of northwest European Russia, were tested for Trichinella larvae; 98 animals (53.3%) were found to be positive. The highest prevalence was detected in wolf (97.5%). Trichinella nativa was the most common species detected (98%). The diet of wolves was investigated by examining the stomach contents of 62 animals (75.6% of the total number of wolves examined for Trichinella). It consisted mainly of dog (36.4% of the total number of occurrences of all food items, PFO) and moose (31.2 PFO); however, during the hunting seasons of 1998-1999 and 1999-2000, skinned wolf carcasses were left in the forest as bait (567 carcasses, about 18,000 kg). This very high prevalence of Trichinella infection, the highest ever detected in a natural population of carnivores, could be explained by carnivore-carnivore transmission, influenced by the hunting practices adopted in the study area.