Оцінка якості води річки Іршавка

Abstract

The Irshavka River water is constantly exposed to anthropogenic impact. So it's ecological state was monitored. There are wastewater treatment facilities on the river Irshavka banks for thetreatment of sewage of centralized water supply and sewerage municipal of the Irshava city. The water of the river is also used by the local population for recreational (fishing, swimming etc.) and agricultural (irrigation of land, livestock watering) purposes. The Irshavka River water quality assessment was carried out during the spring and autumn periods of 2018-2020. Seasonal assessment of river water quality was performed some hydrophysical (transparency, odor, color) and hydrochemical (pH, anions: nitrates, nitrites, ammonium, phosphates, sulfates, chlorides, total iron content, total hardness and permanganate oxidizability) indicators. The results of hydrophysical parameters monitoring of fishery water quality show positive dynamics during the three-year period. None of the determined water indicators (transparency, odor, color) does not exceed the normalized indicators, and their values did not change seasonally during 2018-2020. This fact indicates the minimal anthropogenic impact and natural self-restoration of the water of these rivers. The transparency indicator varies between 32-39 cm, the smell – less than 2, the color equals 10-17 degrees. Monitoring data of the Irshavka River natural water state show that its quality does not change significantly in different phases of the water regime and periods of the year. Normalized indicators that characterize the quality of surface waters do not exceed the maximum allowable concentrations for fishery waters. This indicates the first class and 1-2 category of water quality. Due to the peculiarity of the geological area, exceeding the normalized values several times is observed only for total iron and manganese. Comparison of the concentration of some anions: phosphate ions, nitrate ions, nitrite and ammonium ions in water samples of the studied river showed a negative trend from 2018 to 2020. Their content does not exceed the normalized values, but is much closer to the MPCfw. In 2020, the concentrations of these anions in the sample taken at the point of discharge of treated municipal water (sample №3) were respectively: ammonium ions: 0.48 ± 0.03 mg/dm³; nitrite ions: 0.07 ± 0.02 mg/dm³; nitrate ions: 39.8 ± 0.2 mg/dm³; phosphate ions 2.45 ± 0.2 mg/dm³, which is slightly higher than in 2018: ammonium ions: 0.43 ± 0.01 mg/dm³; nitrite ions: 0.07 ± 0.01 mg/dm³; nitrate ions: 34.8 ± 0.2 mg/dm³; phosphate ions 1.28 ± 0.2 mg/dm³. These hydrochemical parameters have less values in river water samples taken above municipal wastewater treatment plants. The water quality in the Irshavka River matches the regulatory requirements for fishery waters, despite the emergency condition of wastewater treatment facilities. Renovation of the Loza village treatment plants by modernization of the facilities will provide an opportunity to improve the water quality of the Irshavka River and stabilize the ecological state of the region.