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Research article - Peer-reviewed, 2022

Lead exposure in American black bears increases with age and big game harvest density

Brown, Ludovick; Rosabal, Maikel; Dussault, Christian; Arnemo, Jon M.; Fuchs, Boris; Zedrosser, Andreas; Pelletier, Fanie


Hunting has multiple consequences for wildlife, and it can be an important source of environmental pollution. Most big game hunters use lead (Pb) ammunition that shed metal fragments in the tissues of harvested animals. These Pb fragments become available to scavengers when hunters discard contaminated slaughter remains in the environment. This exposure route has been extensively studied in avian scavengers, but few studies have investigated Pb exposure from ammunition in mammals. Mammalian scavengers, including American black bears (Ursus americanus), frequently use slaughter remains discarded by hunters. The objective of this study was to investigate whether big game harvest density influenced long-term Pb exposure in American black bears from Quebec, Canada. Our results showed that female black bears had higher tooth Pb concentrations in areas with higher big game harvest densities, but such relationship was not evident in males. We also showed that older bears had higher tooth Pb concentrations compared to younger ones. Overall, our study showed that Pb exposure increases with age in black bears and that some of that Pb likely comes from bullet fragments embedded in slaughter remains discarded by hunters. These results suggest that hunters may drive mammalian scavengers into an evolutionary trap, whereby the long-term benefits of consuming slaughter remains could be negated due to increased Pb exposure.


Ursus americanus; Scavenger; Pb; Ammunition; Bioaccumulation; Hunting

Published in

Environmental Pollution
2022, volume: 315, article number: 120427

Authors' information

Brown, Ludovick
University of Sherbrooke
Rosabal, Maikel
University of Quebec Montreal
Arnemo, Jon M. (Arnemo, Jon)
Inland Norway University of Applied Sciences
Swedish University of Agricultural Sciences, Department of Wildlife, Fish and Environmental Studies
Fuchs, Boris
Inland Norway University of Applied Sciences
Zedrosser, Andreas
University of Natural Resources and Life Sciences, Vienna
Pelletier, Fanie
University of Sherbrooke

UKÄ Subject classification

Environmental Sciences
Fish and Wildlife Management

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