Предпосылки техногенной метаморфизации ионного состава воды р. Надым в условиях глобальных климатических изменений

The hydrochemical regime changes of Nadym River near city of Nadym from the start of regular observations in 1955 till 2016 in conditions of anthropogenic impact and global climate change was reviewed. Shown, that the relations between the major ion concentrations (ions of sodium and potassium, calcium, magnesium, chlorides, sulfates and bicarbonates) and water discharge from 1980 are getting weaker down to insignificant. Likewise, disturbances the natural ratio between the major ions, which most pronounced in a strong positive trend of the sulfate ions content in river water, are arise. The data on the long-term dynamics of the main ions  in the main phases of the hydrological regime (spring high water, summer-autumn and winter low water) are presented. The probable causes of the observed preconditions to technogenic metamorphization of Nadym River ionic composition are considered: impact of untreated sewage discharge, atmospheric transport of anthropogenic and natural sulfur compounds, and pollution by mineralized formation waters. It has been suggested that the sulfates increased during all phases of the hydrological regime, including the winter low water, is associated with contamination of ground waters as a result of filtration and leakage of drilling waste from slurry barns. Probably, it occurs due to the degradation of their natural waterproofing layer of permafrost rocks under the influence of global climate change.