Stanols in lake sediments of Central Siberia as an indicator of anthropogenic impact

Abstract

The bottom sediments of the lakes contain biochemical markers of fecal intake, which have been renewed interest in the last few years. This analysis is one of the newest trends in paleolimnology. Fecal markers include sterols recovered by the intestinal microflora – stanols, which are indicators of fecal intake into reservoirs. Relative to other mammals, humans produce the largest amount of coprostanol. Therefore, based on its presence in bottom sediments, the dynamics of human presence in early times can be reconstructed, as well as the fecal anthropogenic load on reservoirs. Using the gas chromatography method with mass spectrometric detection, for the first time we estimated the contents of coprostanol, epicoprostanol, 5α-cholestanol and cholesterol in the bottom sediments of Lakes Peyungda and Zapovednoye (Evenkia, Krasnoyarsk Krai), and also estimated the indices R1 and R2, reflecting the human contribution to fecal intake. The absence of an increase in the proportion of coprostanol in both lakes may indicate a slight anthropogenic impact. Both in the modern period and in earlier times (about 5000 years for Peyungda and 2500 years for Zapovednoye), there were probably no settlements near the lakes.