Разработка региональных ПДК для водотоков: Ерик Бешеный, река Солёная бассейна Нижнего Дона

Abstract

The purpose of the work is to conduct a statistical analysis of long-term hydrochemical data on water quality in the small Solenaya River and its tributary Erik Beshenny of the Lower Don basin, to develop regional maximum permissible concentrations (MPCreg) of salt-forming ions. The relevance of the study is due to contradictions in the current environmental legislation. The objects of the study were small rivers – receivers of drainage and waste water (DWW) from reclaimed lands of the Central irrigated district of the Rostov region – the Solenaya River and its tributary Erik Beshenny. To calculate the regional MPC, we used a methodology based on estimates of nonparametric statistical indicators, which allows us to effectively take into account the volume of statistical samples under consideration and their variability. The paper presents a statistical analysis of hydro chemical data in the background for the period 2008-2020 years. It is established that the main problem of the natural water quality in the water bodies under consideration is the high content of salt-forming ions and the mineralization index. It is shown that the statistical distribution of the salt-forming ions under consideration and the mineralization index signifi cantly differs from the normal one. The biological oxygen consumption (BOCtotal) indicator is within the limits of the federal standard for fishery water bodies of category I. Regional MPCs were calculated for sulfates 552 and 647 mg/l and sodium – 309 and 210 mg/l for Er. Beshenny and R. Solenaya, respectively. The remaining salt-forming ions have concentrations below the permissible federal MPC. In order to minimize violations of the water legislation, the Management «Rostovmeliovodhoz» (land reclamation and agricultural water supply in the Rostov region), despite being classifi ed as objects of Category III, is recommended to calculate the normatively permissible discharge (NPD) for salt-forming ions, taking into account background concentrations, including for the two above-mentioned indicators in the water bodies under consideration – taking into account the developed MPCregs.