Urban impact on water quality in the rivers of Central Russia

Abstract

Comparative analysis of the urban impact on water quality in the main rivers of Central Russia has been performed based on hydrochemical observations dataset for the period 2005-2019. It was obtained from monitoring results at the gauging stations located upstream and downstream of 11 cities in the studied region. The pollution level was estimated by comparison of the annually-averaged concentration values for 43 water quality indicators with their defined maximum permissible concentrations. The most substantial growth in concentrations downstream of the cities compared to their upstream values was revealed for heavy metals, nitrogen compounds, phosphates and oil products. A much less significant negative impact was imposed by cities on transparency, oxygen and major ions content. The cities were ranked by the total number of hydrochemical indicators which concentrations 1) increase downstream of cities, 2) exceed the maximum permissible concentrations before and after entering cities, 3) exceed the maximum permissible concentration before and after entering cities while sufficiently increasing (> 10%) at the downstream station. Additionally, the indicators were identified that experienced the most considerable impact from the urban areas. Among the studied cities, three groups were identified differing from each other in the degree of impact on the river water quality.