Total Mercury Content in Amphibian Organs from the Ussuri Broadleaf and Mixed Forests Ecoregion

<p indent="0mm">The distribution of exposure to Hg in amphibians remains unknown on most continents. The Ussuri broadleaf and mixed forests ecoregion is a region of high biodiversity, the nine species of amphibia living on its territory are prey for over 25 threatened and rare vertebrate species. To understand the potential risks to wildlife, we measured the total mercury (THg) content in the Siberian wood frog (<italic>Rana amurensis</italic>) and the Sakhalin toad (<italic>Bufo sachalinensis</italic>) from the same locality. In total THg level was measured in 134 samples of liver, kidneys, and muscles via atomic absorption. Mean THg concentrations mg/kg dry weight (DW) were 0.055 ± 0.018 in muscles, 0.126 ± 0.040 in kidneys, and 0.140 ± 0.062 in liver in the immature Siberian wood frogs. In the adults of Siberian wood frogs, the mean THg concentrations were 0.035 ± 0.005 in muscles, 0.081 ± 0.006 in kidneys and 0.030 ± 0.005 in liver. Statistically significant differences in THg content between the two age groups were obtained only for the liver (<italic>p</italic> = 0.008). The mean THg of the Sakhalin toad was 0.058 ± 0.007 in muscles, 0.085 ± 0.009 in <?A3B2 tlb=13.11pt?>kidneys, and 0.137 ± 0.019 in liver. THg content in immature Siberian wood frogs and Sakhalin toads showed no statistically significant differences. THg correlations between tissues and organs were found. The THg content in amphibians was found to be comparable with the THg content of producers in terrestrial ecosystems and lower compared to species from other classes of terrestrial vertebrates. There is an assumption that other species of tailless amphibians of the genera <italic>Rana</italic> and <italic>Bufo</italic> may contain similar levels of total mercury in anthropogenically unpolluted or slightly polluted boreal landscapes of the Russia. For those boreal ecosystems that are already subject to pollution, our results may be used to justify specific actions when restoring ecosystem services, structures, and functions efficiently and effectively. <?A3B2 tlb?> <?Pub Caret 23?>