Hydrochemical characteristics and water quality assessment of surface and ground waters in the transboundary (Russia/Ukraine) Seversky Donets basin

Hydrochemical investigations were carried out at 39 locations, including surface water, springs and wells from August to October 2013 to assess water quality in the transboundary Russia/Ukraine water basin of the Seversky Donets River (98,900 km2). The studied area comprised three large industrial regions of Northeastern Ukraine—Kharkiv, Donets and Lugansk, what plays an important socioeconomic role as a major source of industrial and drinking water supply to about 5 M inhabitants. The aim of the study was to evaluate the distribution of trace elements in the watershed and to assess water quality according to the national environmental and health limits. River water sampling was done on the Udy, Lopan, Oskol and Seversky Donets Rivers. Groundwater was sampled on left and right river banks nearby selected river sampling sites. Results showed that the interaction of water with geological formations, mainly Cretaceous carbonate rocks, loams and evaporation, was the predominant natural factor that influenced surface and groundwater chemistry. Evaporation, together with the additional anthropogenic inputs, was the reason for high mineralization of groundwater in the Kharkiv city region. Nutrient pollution (nitrates) was detected in groundwater in the territory of smaller settlements, where the population use groundwater for household needs and drinking supply. Among trace elements (Cr, As, Ni, Cu, Zn and Pb), only Pb and Zn were found at over 1.2–1.5 times of drinking water limits in the Udy River in the region of Kharkiv city.