Оцінка екологічного ризику внаслідок впливу комунальних об’єктів на поверхневі води

Abstract

For the first time, a comparative analysis of two methods for determining the environmental risk of natural surface water body based on real averaged data from long-term observations of the Seversky Donets River, located near Izyum in the area of wastewater discharge from municipal water supply and sewerage company. The combinatorial index of water pollution is calculated and an integrated assessment of the ecological status of surface waters is obtained, which is based on the multiplicity of exceedances of the maximum allowable concentration of individual components. It is established that the wastewater of the enterprise worsens the condition of the studied water because the values of the index 500 m to the discharge site (fluctuations in the range from 6.30 to 8.08) are greater than the value of KIZV 500 m below the discharge site (fluctuations in the range from 6.93 to 8.15), especially the warm period of the year. For the first time it was established that the use of "Method 1" of environmental risk assessment by hydro-chemical parameters of the water body does not give an objective description of the risk of hazardous objects on water resources and makes it impossible to reliably assess the degree of environmental risk from sewage. the calculated risk indicators 500 m below the discharge site range from 0.91 to 1.15. It has been proven that the risk assessment according to "Method 2" depends entirely on the values of the water pollution index, and is obtained by arithmetic operations with the index and certain constants, which indicates the subjectivity of the approach and low reliability of environmental risk assessment. The results of the calculation obtained by "Method 2" show that the impact of wastewater increases the value of environmental risk, in particular for July - September - from acceptable to unacceptable (values from 8.81‧10-7 to 1.57‧10-6). However, this technique does not give a correct numerical value for risk values exceeding 4.99∙10-6.