More than 400 seal mummies and skeletons are now mapped in the northern part of James Ross Island, Antarctica. Decomposing carcasses represent a rare source of both organic matter and associated elements for the soil. Owing to their high trophic position, seals are known to carry a significant mercury body burden. This work focuses on the extent of the mercury input from seal carcasses and shows that such carcasses represent locally significant sources of mercury and methylmercury for the environment. Mercury contents in soil samples from the surrounding areas were determined using a single-purpose AAS mercury analyzer. For the determination of methylmercury, an ultra-sensitive isotopic dilution HPLC-ICP-MS technique was used. In the soils lying directly under seal carcasses, mercury contents were higher, with levels reaching almost 40 μg/kg dry weight of which methylmercury formed up to 2.8 % of the total. The spatial distribution implies rather slow vertical transport to the lower soil layers instead of a horizontal spread. For comparison, the background level of mercury in soils of the investigated area was found to be 8 μg/kg dry weight, with methylmercury accounting for less than 0.1 %. Apart from the direct mercury input, an enhanced level of nutrients in the vicinity of carcasses enables the growth of lichens and mosses with accumulative ability with respect to metals. The enhanced capacity of soil to retain mercury is also anticipated due to the high content of total organic carbon (from 1.6 to 7.5 %). According to the results, seal remains represent a clear source of mercury in the observed area.

Department of Chemistry Faculty of Science Masaryk University Kotlářská 2 611 37 Brno Czech Republic

Department of Chemistry Faculty of Science Masaryk University Kotlářská 2 611 37 Brno Czech Republic Institute of Analytical Chemistry The Czech Academy of Sciences v v i Veveří 97 602 00 Brno Czech Republic

Department of Public Health Faculty of Medicine Masaryk University Kamenice 5 625 00 Brno Czech Republic Department of Chemistry Faculty of Science Masaryk University Kotlářská 2 611 37 Brno Czech Republic

Department of Respiratory Diseases and TB Faculty of Medicine Masaryk University Kamenice 5 625 00 Brno Czech Republic Department of Respiratory Diseases and TB University Hospital Brno Jihlavská 20 625 00 Brno Czech Republic

Research Centre for Toxic Compounds in the Environment Faculty of Science Masaryk University Kamenice 5 625 00 Brno Czech Republic

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