On January 23rd and February 1st 2020, the first two publications of the BearHealth project appeared! The first publication concerns the level of metals and metaloids in the blood and hair of brown bears and is the result of research conducted as part of module 4 of the project, in which we investigate the exposure to toxins in brown bear populations under study. Under the lead of Dr. Maja Lazarus and her team from the Institute for Medical Research and Occupational Health (Zagreb, Croatia), we investigated the level of five non-essential metal(loid)s (As, Cd, Hg, Tl, Pb) and nine essential metals (Mg, Ca, Mn, Fe, Co, Cu, Zn, Se, Mo) in hair and blood samples of captive and free-ranging European brown bears collected in Croatia and Poland.
It turned out that among the metals and metalloids tested, lead turned out to be the compound with the highest concentrations, both in blood and hair samples. In four out of 35 individuals, blood concentration of lead was above 100 μg/L. In general, females showed higher concentrations of metals and superoxide dismutase activity. We also examined samples from bears in captivity, in which we found higher levels of calcium and magnesium in the blood than in free-living bears, while lower levels of SOD, as well as manganese, zinc and cadmium. Cobalt, cadmium, thallium and lead levels in captive bear hair were also lower than those of free-living bears.
The study also contributed from our collaborators from the Faculty of Veterinary Medicine, University of Zagreb, Ruđer Bošković Institute in Zagreb, Tatra National Park and the Institute of Environmental Biology of the University of Wrocław.
The publication can be viewed at the website of Environmental Research journal https://doi.org/10.1016/j.envres.2020.109166
The second publication is the result of research conducted within module 1, in which we examine the level of stress in the studied populations. Working with hair samples in the laboratory is very time consuming, especially if the methods of sample collection vary and to unify the sample set requires e.g. cutting the follicles. Because their presence or absence in the sample may affect the results, we decided to conduct an experiment that would help us understand the scale of this impact. We compared cortisol concentrations in paired subsamples of hair with and without follicles from 30 free-ranging Scandinavian brown bears.
Observed cortisol values were significantly greater in samples with follicles present, independently on the sex or age of the individuals. This is a very important result from the methodological point of view in studies using hair or other keratinous tissues as a medium. Unification of the methods will allow comparisons across stduies and will optimize the workload in ecophysiological research.
In this study we cooperated with Toxicology Centre of the University of Saskatchewan in Saskatoon (Canada), RGL Recovery Wildlife Health & Veterinary Services, Department of Veterinary Biomedical Sciences of the University of Saskatchewan, the Faculty of Environmental Science and Natural Resource Management of the Norwegian University of Life Sciences and the Department of Natural Sciences and Environmental Health of the University of South-Eastern Norway.
This publication can be downloaded from the website of Conservation Physiology journal https://academic.oup.com/conphys/article/8/1/coaa003/5719526