ИСТИНА

Northern rivers transport huge quantities of water and constituents from the continents to the Arctic Ocean. Snow and ice melt in Polar regions are associated with dramatic changes in the hydrological regime and significantly enhance erosional processes. Such changes are the most important driver of the hydrological cycle of Polar rivers and dominate the fluxes of dissolved and particulate substances from land to the Arctic Ocean. This study aims at understanding interbasinal and seasonal variations of metals and metalloids (B, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Mo, Cd, Sb, Sn, W, Pb, U) at the lower Ob, Yenisey, Lena and Kolyma rivers, as well as Selenga River catchment which represents the upper part of Yenisey river basin – the region most subjected to anthropogenic impact (most agriculture and mining). The dataset on elements in river water and suspended solids collected during different hydrological seasons in 2011-2022 includes about 2500 water and suspended matter samples. Baikal Lake catchment dataset contains also unique results of threefold sampling campaign conducted in 2022, that embraced 12 smaller tributaries of the lake and 3 hydrological seasons including winter low-water. The approach enables to differentiate background, baseline, and anthropogenic levels of dissolved and suspended forms of metal(loid)s. The study emphases average regional concentration levels of metal(loid)s for each river and reveals elevated relative pollution of the Ob compared to the Yenisey, Lena and Kolyma Rivers, as well as seasonal and cross-sectional variations. Both for large and small rivers, main features of partitioning of chemical elements were found quite similar. Firstly the features were revealed by D,P-analysis for the Selenga River basin. The results were used to calculation particulate flux of studied metals and metalloids which constitute over 13% of total annual sediment load for the Ob RIver, 31% for the Yenisey River, 19% for the Lena River, and 20% for Kolyma River.