sustainability Article Source Apportionment of Inorganic Solutes in Surface Waters of Lake Baikal Watershed Mikhail Y. Semenov 1,*, Yuri M. Semenov 2, Anton V. Silaev 2 and Larisa A. Begunova 3 1 Limnological Institute of Siberian Branch of Russian Academy of Sciences, Ulan-Batorskaya St. 3, 664033 Irkutsk, Russia 2 V.B. Sochava Institute of Geography of Siberian Branch of Russian Academy of Sciences, Ulan-Batorskaya St. 1, 664033 Irkutsk, Russia;
[email protected] (Y.M.S.);
[email protected] (A.V.S.) 3 Department of Chemistry and Food Technology, Institute of High Technologies, Irkutsk National Research Technical University, Lermontov St. 83, 664074 Irkutsk, Russia;
[email protected] * Correspondence:
[email protected] Abstract: The aim of this study was to obtain a detailed picture of the origin of the anthropogenic and natural inorganic solutes in the surface waters of the Lake Baikal watershed using limited data on solute sources. To reveal the origin of solutes, the chemical composition of water was considered as a mixture of solutes from different sources such as rocks and anthropogenic wastes. The end-member mixing approach (EMMA), based on the observation that the element ratios in water uncorrelated with one another are those that exhibit differences in values across the different types of rocks and anthropogenic wastes, was used for source apportionment. According to the results of correlation analysis, two tracers of sources of most abundant ions present in riverine waters were selected. The first tracer was the ratio of combined concentration of calcium and magnesium ions to concentration Citation: Semenov, M.Y.; Semenov, of potassium ion ((Ca2+ + Mg2+)/K+), and the second tracer was the ratio of sulfate and bicarbonate Y.M.; Silaev, A.V.; Begunova, L.A.