Assessment of environmental risk of groundwater quality deterioration within Siversky Donets river basin

An adaptation of the national water resources management system in accordance with the requirements of European legislation creates the legislative basis for reforms im- plementation in the field of monitoring and water use. The basin management principle started to be applied, according to which surface and groundwater arrays are the water resources management units. The preliminary groundwater array status assessment (both quantitative and qualitative) is a necessary procedure that enforces the development of appropriate monitoring program and measures elaboration in order to improve groundwater ecological status. This study tested a methodology of groundwater deterioration risk assessment as a tool for previous groundwater array cological status estimation. The research provides an approbation of the methodology in relation to groundwater arrays identified and delineated within Siversky Donets river basin (that covers Kharkiv, Donetsk and Lugansk regions). Surface water and groundwater are affected by significant anthropogenic pressures in form of pollution from point sources of heavy industry facilities. A risk model comprises groundwater vulnerability map and simulated model of anthropogenic pressure magnitude distribution reflecting the impact extent of the main sources of groundwater pollution. Vulnerability map was developed using the tool of input factors weight index estimation. Authors considered the following factors as determining – soils characteristic, aeration zone characteristics, geological environment of groundwater arrays of Cenozoic-Mesozoic group. The pollution load index was calculated. Input data for calculation are concentrations of hazardous substances (metals, semimetals, halogens and nitrates and phenol compounds) measured in groundwater samples during the 2017 monitoring year period. The results of the value interpolation of calculated pollution load index reproduce the focal (point) nature of groundwater pollution and indicates the significant groundwater pollution of Quaternary and Upper Cretaceous, both Carboniferous aquifers and corresponding groundwater arrays. A logical matrix is created on the basis of a combination of pres- sure magnitudes and vulnerability classes. The area of each class of risk is calculated within groundwater arrays with zonal statistic technique. Consequently, each groundwater array is assigned with preliminary estimated risk category. Created model enables to per- form previous groundwater array status assessment. The proposed model expected to be more useful after the data on pollution from diffuse sources obtaining and its validation after the first stage of surveillance monitoring realization.