Concentration of lead, cadmium, and mercury in tissues of European beaver (Castor fiber) from the north-eastern Poland

Abstract

The aim of the study was to determine the concentrations of lead (Pb), cadmium (Cd), and mercury (Hg) in the liver, kidneys, and muscles of European beavers (Castor fiber) and thus to evaluate the degree of heavy metals contamination in Warmia and Mazury region in Poland. The study was conducted on free-living beavers captured in region of Warmia and Mazury during autumn 2011. Concentrations of the elements were determined by atomic absorption spectrometry. The presence of the metals was detected in all individual tissue samples. Mean Pb and Hg concentrations were relatively low. However, the high mean Cd level, especially in the kidneys (7.933 mg/kg) and liver (0.880 mg/kg) was demonstrated. Despite the fact that region of Warmia and Mazury is considered to be "ecologically clean", the conducted studies indicate that systematic monitoring for the presence of heavy metals is necessary not only in industrialised but also in agricultural regions, as well as in natural ecosystems.

Impacts of Pollutants on Beavers and Otters with Implications for Ecosystem Ramifications

“…Elevated levels of cadmium in tissues have been reported in multiple studies in both polluted areas and areas considered “ecologically clean” (Fimreite et al ; Giżejewska et al ; Giżejewska et al ; Nolet et al ; Zalewski et al ). Fimreite et al () found that beavers’ preferred plant species (aspen [ Populus spp.…”

“…For beavers, the focus has been on the accumulation of cadmium in tissues due to their herbivorous nature and consumption of plant material exposed to hazardous concentrations of this and other metals (Nolet et al ). For example, mercury accumulates in both beavers (Giżejewska et al ; Sheffy and Amant ; Wren ) and beaver wetlands (Driscoll et al ; Painter et al ). Beavers prefer an herbaceous and woody diet for both consumption and engineering of dams and dens (Bryzski and Schulte ), leaving them susceptible to pollution in the aquatic ecosystem and plant material.…”

“…Mercury poisoning is considered a risk factor for river otter survival because it is a ubiquitous neurotoxin that readily bioaccumulates in the food chain (Basu et al ; Basu et al ; Dornbos et al ). Concentrations of mercury have been observed in various tissues in otters (Evans et al ; Dornbos et al ; Sleeman et al ; Wren ; Wren et al ; Giżejewska et al ). Several authors have found quantifiable mercury levels in the brain (Dornbos et al : Evans et al ), with significant mercury‐associated neurochemical changes (Basu et al ; Basu et al ; Basu et al ; Basu et al ; see Basu and Head for a complete review; Dorbos et al 2013).…”

Beavers indicate metal pollution away from industrial centers in northeastern Poland

“…Previous studies reported essential and toxic metals in beaver (family: Castoridae) tissues obtained from industrial areas, generally regarded as polluted (Hillis and Parker 1993 ; Zalewski et al 2012 ), agricultural regions (Fimreite et al 2001 ), and natural ecosystems (Wren 1984 ; Zalewski et al 2012 ; Giżejewska et al 2014 ). Beavers are semi-aquatic, territorial herbivorous rodents feeding on the bark, shoots, and leaves of a wide variety of woody plants including willow ( Salix sp.)…”

“…In this study, our aim was to use the Eurasian beaver as a bioindicator organism (i) to assess trace element contents in a region away from major industrial centers and (ii) to evaluate the degree of contamination against legal Cd and Pb levels recommended by the European Commission in farm animal edible tissues (European Commission 2006 ) with regard to the lack of an official threshold for wildlife (Giżejewska et al 2014 ). Specifically, we measured concentrations of Cd, Pb, Cu, and Zn in liver and kidney of wild beavers.…”