Modeling Management and Climate Change Impacts on Water Pollution by Heavy Metals in the Nizhnekamskoe Reservoir Watershed

Yury Motovilov,Tatiana Fashchevskaya

doi:10.3390/w13223214

Abstract

The semi-distributed physically based ECOMAG-HM model was applied to simulate the cycling of the heavy metals (HM) Cu, Zn, and Mn, and to identify spatial and temporal patterns of heavy metal pollution in water bodies of a large river catchment of the Nizhnekamskoe reservoir (NKR) in Russia. The main river of the catchment is the Belaya River, one of the most polluted rivers in the Southern Urals. The model was tested against long-term data on hydrological and hydrochemical monitoring of water bodies. It is shown that the pollution of rivers is formed mainly due to diffuse wash-off of metals into rivers from the soil-ground layer. Numerical experiments to assess the impact of water economic activities on river pollution were carried out by modeling scenarios of changes in the amount of metal discharged with wastewater, a disaster with a salvo discharge of pollutants, and the exclusion of anthropogenic impact on the catchment to assess self-purification of the basin. Modeling of chemical runoff in accordance with the delta-change climatic scenario showed that significant changes in water quality characteristics should not be expected in the near future up to 2050.

Highlights

Heavy metals (HMs) are one of the most dangerous pollutants of the environment
The specific objectives of the study were (a) to evaluate the capabilities of the model for assessing HM pollution of river waters in various sections of the river network to solve the problem of designing a hydrochemical monitoring network; (b) to assess the contributions of diffuse and point anthropogenic sources to HM pollution in the Nizhnekamskoe reservoir (NKR) watershed; (c) to assess changes in water quality of water bodies under various scenarios of anthropogenic load on the river basin; and (d) to assess changes in the hydrological and hydrochemical regime of rivers under a scenario of possible climatic changes
The semi-distributed, physically based ECOMAG-HM model developed for modeling the hydrochemical cycle of heavy metals at the catchment scale was calibrated and verified for the large watershed of the Nizhnekamskoe reservoir according to hydrometeorological, hydrochemical, and water management monitoring data

Summary

Introduction

Heavy metals (HMs) are one of the most dangerous pollutants of the environment. The main anthropogenic sources of HM are various enterprises of ferrous and non-ferrous metallurgy, mining enterprises, chemical enterprises, fuel installations, cement plants, electroplating industries, and transport. HMs accumulate relatively in soils, but their removal is slow. HMs are necessary for the processes of vital activity of organisms. Excessive amounts of HM are accumulated by the organs and tissues of hydrobionts and humans, adversely affecting their health and increasing the environmental risks of morbidity [2,3]. One of the main factors of the temporary detoxification of natural waters from HM ions is their adsorption by suspended particles, deposition in the form of poorly soluble inorganic compounds, and burial in bottom sediments

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Conclusion