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Research article - Peer-reviewed, 2021

High concentrations of lead (Pb) in blood and milk of free-ranging brown bears (Ursus arctos) in Scandinavia

Fuchs, Boris; Thiel, Alexandra; Zedrosser, Andreas; Brown, Ludovick; Hydeskov, Helle B.; Rodushkin, Ilia; Evans, Alina L.; Boesen, Amanda H.; Graesli, Anne Randi; Kindberg, Jonas; Arnemo, Jon M.;


Exposure to lead (Pb) is a global health problem for both humans and wildlife. Despite a dramatic decline in human Pb exposure following restrictions of leaded gasoline and industry and thereby an overall reduction of Pb entering the environment, Pb exposure continues to be a problem for wildlife species. Literature on scavenging terrestrial mammals, including interactions between Pb exposure and life history, is however limited. We quantified Pb concentration in 153 blood samples from 110 free-ranging Scandinavian brown bears (Ursus arctos), 1-25 years old, using inductively coupled plasma sector field mass spectrometry. We used generalized linear models to test effects of age, body mass, reproduction status and spatial distribution on the blood Pb concentrations of 56 female bears. We sampled 28 females together with 56 dependent cubs and paired their blood Pb concentrations. From 20 lactating females, we measured the Pb concentration in milk. The mean blood Pb concentration was 96.6 mu g/L (range: 38.7-220.5 mu g/L). Both the mean and range are well above established threshold concentrations for developmental neurotoxicity (12 mu g/L), increased systolic blood pressure (36 mu g/L) and prevalence of kidney disease in humans (15 mu g/L). Lactating females had higher Pb blood concentrations compared to younger, non-lactating females. Blood Pb concentrations of dependent cubs were correlated with their mother's blood Pb concentration, which in turn was correlated with the Pb concentration in the milk. Life-long Pb exposure in Scandinavian brown bears may have adverse effects both on individual and population levels. The high blood Pb concentrations found in brown bears contrast the general reduction in environmental Pb contamination over the past decades in Scandinavia and more research is needed to identify the sources and pathways of Pb exposure in the brown bears.


Lead; Blood; Milk; Ursus arctos; Carnivora

Published in

Environmental Pollution

2021, volume: 287, article number: 117595

Authors' information

Fuchs, Boris
Inland Norway University of Applied Sciences
Thiel, Alexandra
Inland Norway University of Applied Sciences
Zedrosser, Andreas
University of Bodenkultur Wien
Brown, Ludovick
Université de Sherbrooke
Hydeskov, Helle B.
Nottingham Trent University
Rodushkin, Ilia
Lulea University of Technology
Evans, Alina L.
Inland Norway University of Applied Sciences
Boesen, Amanda H.
Inland Norway University of Applied Sciences
Graesli, Anne Randi
Inland Norway University of Applied Sciences
Swedish University of Agricultural Sciences, Department of Wildlife, Fish and Environmental Studies
Norwegian Institute for Nature Research (NINA)
Arnemo, Jon M. (Arnemo, Jon)
Inland Norway University of Applied Sciences

UK√Ą Subject classification

Environmental Sciences

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