ISSUES OF DRINKING WATER QUALITY IN THE WESTERN PART OF CRIMEA

Abstract

Introduction. Until 2014, water supply in Sevastopol city and its municipal districts was combined due to its own surface and underground waters as well as a water conduit running from the Mezhgornoye reservoir located in the Saksky district and filled with the Dnieper waters of the North Crimean Canal. After 2014, this source was shut off. Therefore, it became important to conduct a comparative analysis of the quality of drinking water supplied to the settlements of this territorial entity. Purpose of the study: The study is aimed to assess the quality of drinking water and perform its analysis in Sevastopol city and nearby settlements, taking into account the increase in water intake from rivers and underground sources in recent years. Methods. Objects of the study are surface and underground water supply points, and drinking water for consumers. We used standard methods for the analysis of drinking water with an assessment of its physical, chemical and sanitary-bacteriological indicators using analysis of variance (AoV) methods. Water quality was assessed by the specific combinatorial index of water pollution. Using GIS technologies, maps were built to visualize a number of indicators: chemical oxygen consumption and data on the water pollution complexity coefficient at the stage when consumers receive water from the central water supply system (for all municipal districts). Results. It was established that sanitary and microbiological indicators of tap water quality — by the total microbial count, total coliform bacteria and thermo-tolerant coliform bacteria — immediately before being fed to the central water supply system in the Southern and Northern districts of Sevastopol, did not exceed sanitary standards. Due to the considerable length of the distribution networks and their high deterioration, secondary pollution of drinking water is currently taking place. In a number of municipal districts, it was revealed that the key indicators being assessed exceeded the norms of the State Sanitary Rules and Regulations. For the first time, with the help of GIS technologies in the ArcGis 10.4 software shell, specific ranks of drinking water pollution levels were distinguished for individual municipal districts, which made it possible to visualize the dynamic characteristics of polluting ingredients taking into account their territorial affiliation.