Relationship between heavy metal accumulation and histological alterations in voles from alpine and forest habitats of the West Carpathians

Abstract

The interaction between toxic heavy metals and bio-elements in internal organs and femoral bones and their potential impacts on bone structural properties and renal histopathological changes in bank voles and snow voles were investigated. Our results reveal that heavy metals Hg and Pb accumulate more in femoral bones of alpine habitats than forests. In snow voles, the parameters of the primary osteons' vascular canals (length, average perimeter and area) simultaneously decreased with an increase of Pb and Sr. Wider primary osteons' vascular canals of snow voles contained decreased levels of K, but increased Ba. In bank voles, the number of primary osteons increased in alpine habitats along with K, Hg, and Pb accumulation. In the kidneys of bank voles, rising levels of Rb, Hg, and Zn were detected in alpine habitats. Hg increases the most in kidney tissue from alpine habitats in both vole species, and Hg levels (mean value 0.25 μg/g, max. value 0.55 μg/g) in the renal tissues of bank voles from alpine localities are similar to Hg levels from Hg-polluted industrial areas in other studies. This reflects that alpine areas of the Tatra Mountains are highly contaminated with Hg. The intensity of renal hemosiderosis relates significantly to Zn, Fe, and Cu levels in snow voles, with Fe and Zn levels in bank voles from forest habitats, and with Rb in bank voles from alpine habitats. The intensity of tubule necrosis in renal tissues of bank voles from alpine habitats was negatively related to Se content. In bank voles from forest habitats, significant positive correlations were found between the intensity of glomerular hyperplasia and amounts of Zn. The interactions of the detected element's association with bone tissue and internal organs are discussed.

Keywords: Alpine environment; Bone; Chionomys nivalis; Heavy metals; Histopathology; Kidney; Mercury; Myodes glareolus.