Evaluating the Anthropogenic Impact on the Prut River Near Yaremche-town on the Pollution Level Indices of Bottom Sediments

Introduction. One of the most objective and reliable indicators of the state of pollution of the aquatic environment and the overall level of technological load on it is the content of pollutants in bottom sediments (BS). There are no large industrial enterprises in and around Yaremche-town (Ivano-Frankivsk region), so there are no significant discharges of toxic substances into the sewage system, especially directly into the river. However, every year in this picturesque cornerof Prykarpattia the number of sanatoriums, recreation centres, cottage towns and just residential buildings grows. Accord-ingly, the Prut River, which is the pearl of this region, quite often gets untreated runoff, which pollutes not only water but also settles on bottom sediments.The purpose of this study was to assess the anthropogenic load on the Prut River based on a comprehensive environmental analysis of the state of pollution of the bottom sediments of this river upstream and downstream from Yaremche.Methods. Water extracts from bottom sediments were prepared by the recommendations of the relevant regula-tions in the ratio "bottom sediments - water" as 1: 5 in terms of the dry mass of bottom sediments. Laboratory study of hydrochemical parameters of selected samples was performed by gravimetric, titrimetric, photometric and other methods of analysis.Research results. The accumulation of ammonium salts, nitrites and nitrates, which are easily soluble, in the far above the discharge site of wastewater, is obviously due to the significant sorption properties of river sludge, which prevents these ions from being washed away by the flow. At the point of discharge of wastewater from the city, the content of these ions increases and reaches a maximum at point 3 - at a distance of approx. 100 m below the discharge site. Further downstream, their number systematically decreases. A similar distribution of concentrations is observed in the case of phosphates. Their source of getting into the river also, for the most part, belongs to the housing and communal services. A significant contribution to the increased phosphate content in the sample below the discharge is made by urban wastewater, in which even after treatment the concentration of phosphate ions remains quite high. The fact of the presence of oil products in the bottom sediments at the investigated area was revealed. The constant increase in the number of road transport on the banks of this resort river inevitably leads to the ingress of products of incomplete combustion of fuel, uncontrolled spills.Conclusions. Upstream from the place of discharge into the Prut River of treated wastewater in the city of Yaremche, the concentrations of salts-pollutants of the biogenic group are formed due to uncontrolled sources of domestic sew-age. In this area, the pollution of bottom sediments is insignificant, slightly higher at the discharge site, and they are of the greatest importance below the discharge. This fact indicates the growing anthropogenic impact of coastal cities on the state of the river and in general, and pollution of bottom sediments, in particular. For the first time oil products were found in bottom sediments in the studied area. The reason for this phenomenon is the constant increase in the number of vehicles on the banks of this river