Radionuclide and Trace Element Distribution in Grey Wolves (Canis lupus): Implications for Environmental Contamination and Transfer in Terrestrial Ecosystems

Anthropogenic pollution may impose additional pressure on European populations of large protected carnivores due to the systemic toxicity of contaminants such as cadmium, lead, and radiocaesium (137Cs). Our aim was to carry out 137Cs, radiopotassium (40K), and stable element distribution analysis through seven tissues of grey wolves (Canis lupus) from temperate forests of Croatia using ultra-low background gamma-ray spectrometry and ICPMS, respectively. In addition, radiolead (210Pb) massic activity was quantified in femoral bone. The massic activity of 137Cs in the heart, kidney, liver, spleen, lungs, and femoral bone (in decreasing order) ranged from 9–61% relative to muscle and showed strong inter-tissue correlations. However, correlations between radionuclides and their stable analogues in wolf tissues indicated considerable uncertainty in the use of stable element data for radiological risk assessment. In addition, concentration ratios (CRwhole organism-soil) derived from stable element data should be applied with caution when radionuclide data are lacking. Overall, radionuclide activities and element levels not subject to homeostatic regulation in grey wolves were comparable to or lower than those reported for other populations, particularly those from sub-Arctic regions. Despite being apex terrestrial predators, wolves inhabiting temperate ecosystems do not currently appear to be at risk of adverse health effects from exposure to the most relevant inorganic anthropogenic pollutants.