FORECASTING THE RISKS OF NITRATE AND MICROBIOLOGICAL POLLUTION OF SOURCES OF DISTRICT WATER SUPPLY

Abstract

The study is aimed at providing a scientific substantiation ofmethodological approaches to the predictive assessment of risks of nitrateand microbiological contamination of decentralized water supply sources,taking into account the conditions of water quality formation. For thispurpose, a comprehensive investigation of the problem of nitrate andmicrobiological contamination of individual and public water intakefacilities was conducted. This issue has remained one of the most pressingchallenges for rural areas in countries with highly developed agriculturalsectors for many years. The persistent and multifactorial nature of thesetypes of contamination is determined by the combined influence of naturalhydrogeological conditions, the intensity of land use, the technical conditionof engineering infrastructure, and the effectiveness of environmentalcontrol. In this context, the development of a reliable tool enablingindividualized assessment and prediction of nitrate and microbiologicalcontamination risks for each specific water supply source within ruralsettlements becomes particularly relevant. To address this objective, amodified Leopold matrix is proposed as a tool for risk prediction, taking intoaccount the conditions of groundwater quality formation. Decentralized water supply systems are typically associated with risks arising from non-compliance with sanitary and hygienic requirements when selecting locations and arranging both public and private wells. Common violationsinclude the placement of water intakes in close proximity to potentialsources of contamination—such as cesspits, outdoor latrines, sewernetworks, livestock facilities, abandoned shaft wells—as well as theabsence of properly established sanitary protection zones around water 141 ВісникНУВГПintake structures. The results of the predictive assessment make itpossible to identify the key factors determining the formation and spreadof nitrate and microbiological contamination for each studied source. Basedon the adapted Leopold matrix, a unified template has been developed todetermine the category of a facility depending on the established level ofrisk. The assigned category defines the monitoring regime and theimplementation of a set of measures aimed at minimizing the risks ofnitrate and microbial contamination of groundwater aquifers.