Ecological status of surface water of the river Stokhid basin

Abstract

Purpose. The analysis of the surface water quality of the Stokhid river, the definition of the class and the category of water quality. Methods.   Comparative geographic, analytical, generalization and systematization.  Results. Inner annual dynamics of the components of the hydro chemical conditions of surface water composition is closely linked with river runoff, the formation of which occurs due to loss of precipitation and nutrition of groundwater. Based on the analysis of monitoring observations, carried out by the State Environmental Inspectorate in the Volyn region for the period from 2007 to 2017, it has been determined the multi-year time and spatial dynamics of the average annual values of integrated environmental indices by the average values. They are following: in the village Malinovka I_{E aver.} = 2,2 and in Lyubeshiv village I_{E aver.} = 2,4. The water of river Stokhid belongs to the second class of quality ("good", "pure"), to the second category ("very good", "very pure") and subcategories 2 (3) ("very good", " clean" water with a tendency to approach the category of "good", "fairly clean") respectively. Dynamics of average annual values of integral ecological indexes for the worst values in village Malinovka I_{E worst} = 2,6 and in the village Lyubeshiv I_Eworst = 2,8 was characterized by water of the second class ("good", "pure"), third category ("good", "fairly clean"), subcategory 2-3 (water transitions in quality from "very good", "pure" to "good", "fairly clean") and subcategory 3 (2) ("good", "fairly clean" water with a bias to "very good", "clean"). Conclusions. In general, it should be noticed, that when calculating the values of integral ecological indexes, the value of the indexes of trophic and sapro-biological indicators are the worst. Compounds of   Nitrogen was among the substances that determined the water quality as "very poor" and "very dirty". Increased levels of Nitrogen compounds in the Stokhid river is mainly due to the intake of insufficiently treated wastewater, surface runoff from agricultural land and the decomposition of non-living organic matter in the spring.