Dietary items as possible sources of (137)Cs in large carnivores in the Gorski Kotar forest ecosystem, Western Croatia

Sci Total Environ. 2016 Jan 15;542(Pt A):826-32. doi: 10.1016/j.scitotenv.2015.11.004. Epub 2015 Nov 8.

Šprem N¹, Piria M², Barišić D², Kusak J³, Barišić D⁴.

Author information

• ¹University of Zagreb, Faculty of Agriculture, Department of Fisheries, Beekeeping, Game Management and Special Zoology, Svetošimunska cesta 25, 10000 Zagreb, Croatia. Electronic address: nsprem@agr.hr.
• ²University of Zagreb, Faculty of Agriculture, Department of Fisheries, Beekeeping, Game Management and Special Zoology, Svetošimunska cesta 25, 10000 Zagreb, Croatia.
• ³University of Zagreb, Veterinary Faculty, Department of Biology, Heinzelova 55, 10000 Zagreb, Croatia.
• ⁴Laboratory for Radioecology, Centre for Marine and Environmental Research, Ruđer Bošković Institute, PO Box 160, Bijenička 54, 10002 Zagreb, Croatia.

Abstract

The mountain forest ecosystem of Gorski Kotar is distant from any significant sources of environmental pollution, though recent findings have revealed that this region is among the most intense (137)Cs contaminated area in Croatia. Therefore, the aim of this study was to investigate (137)Cs and (40)K load in three large predator species in the mountain forest ecosystem. Radionuclides mass activities were determined by the gamma-spectrometric method in the muscle tissue of brown bear (47), wolf (7), lynx (1) and golden jackal (2). The highest (137)Cs mass activity was found in lynx (153Bqkg(-1)), followed by brown bear (132Bqkg(-1)), wolf (22.2Bqkg(-1)), and golden jackal (2.48Bqkg(-1)). Analysis of 63 samples of dietary items suggests that they are not all potentially dominant sources of (137)Cs for wildlife. The most important source of radionuclides for the higher parts of the food-chain from the study area were found to be the mushroom species wood hedgehog (Hydnum repandum), with a transfer factor TF of 5.166, and blueberry (Vaccinium myrtillus) as a plant species (TF=2.096). Food items of animal origin indicated higher mass activity of radionuclides and therefore are possible moderate bioindicators of environmental pollution. The results also revealed that possible unknown wild animal food sources are a caesium source in the study region, and further study is required to illuminate this issue.
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KEYWORDS:

Canis lupus; Environment pollution; Lynx lynx; Radionuclides; Transfer factor; Ursus arctos