Crimean Rivers: Heavy Metals and Metalloids Content, Seasonal Dynamics, Partitioning and Sources

Rivers are the main source of water supply for the Crimean Peninsula, making their chemical status crucial for the regional water security. The study is based on results of geochemical surveys conducted in 2015 – 2018 during different hydrological phases in rivers of the northern macroslope of the Crimean Mountains (the Salgir, Belbek, Kacha, and Alma) and the southern coast (the Derekoyka, Ulu-Uzen, Demerdzhi, and Uchan-Su). Background levels of most elements in water and suspended matter are comparable to their global averages. In impacted areas metal contents exceed background by up to 10–20 times. Dissolved metal contamination is typical during low-water periods, whereas increased values in suspended matter is primarily associated with flood events. Suspended matter is enriched in Bi, Cd, Sb, Zn, Cu, Sn, Pb, W, and Mn, consistent with the geochemical signature of urban road dust in Crimean cities. Among the rivers of the northern part of Crimea, the highest pollution is typical for the Salgir River, on the southern coast - for the Uchan-Su River. Metal(loid)s inputs to suspended matter is predominantly controlled by natural sources, the highest anthropogenic impact is related to construction activities (releasing calcareous dust), urban wastewater, vehicle emissions, and agricultural practices, particularly vineyards.