engleski

Environmental lead (Pb) exposure in captive and free-ranging European brown bears: Whole blood monitoring 2011-2019

Lead as an ubiquitous environmental pollutant of natural and anthropogenic origin enters a bear’s organism mostly via food and water. It is initially found in the bloodstream bound to red blood cells and reflects recent exposure. As a non-essential metal, lead causes adverse health effects on a developing nervous system (maternal transfer), renal, cardiovascular, haematological, immunological and reproductive system. Unlike in humans or domestic animals, there is no threshold for ursid blood Pb levels. Information about the lead exposure in this predator species is of high conservation interest. Our aim was to compare lead levels across captive and free-ranging brown bears from two European populations (Dinara-Pindos and Carpathian) sampled between 2011 and 2019 using the inductively coupled plasma mass spectrometry (ICP-MS) method. The median (range) level of lead in 32 bears from Croatia and 15 from Poland was 64.0 (5.08 ̶ 187 µg/L) and did not differ between countries. Levels were similar to Scandinavian and Canadian brown bears, three-times higher than in the Yellowstone black bears and three times lower than reported for giant pandas. Free-ranging bears had higher Pb (med 67.8 µg/L) compared to captive individuals (med 32.8 µg/L), although not significantly (t(47) = -1.94, p = 0.058). Blood lead also displayed gender differences (t(47) = -2.26, p = 0.028) with higher levels in female (med 80.6 µg/L) than in male (med 45.1 µg/L) bears. Eleven of the 47 individuals had blood levels over the threshold for an adult human (100 µg/L), but none surpassed the levels considered toxic for large domestic animals.

non-essential metal ; mammal ; pollutant

nije evidentirano