Environmental Risk Assessment and Regulatory Rating of Water Sources along the Yangtze River’s Nanjing Section under the Influence of Multiple Risk Sources

Qi Zhou,Jianjian Wang,Jing Zhang,Yong Niu

doi:10.3390/su13031484

Abstract

To complement the current studies of risk assessment on water sources which seldom consider the distribution effects of multiple risk sources concentration, and improve the efficiency of water source supervision, this study establishes a method system for risk assessment of water sources and regulatory rating evaluation under the distribution effects of multiple risk sources concentration. The method system includes: (1) utilizing the single-risk source impact index to characterize the risk impact degree of the single-risk source on the water source, the index calculation method of single-risk source impact considers the risk degree and the distribution location of risk source; (2) using the multiple risk sources impact index to characterize the risk impact degree of the multiple risk sources on the water source, the index calculation method of multiple risk sources considers the impact index of single-risk source, the number of risk sources, and the distribution concentration of multiple risk sources; (3) the environmental risk assessment and regulatory rating evaluation method consider multiple risk sources impact index, anti-risk ability of water source, and the importance of water source. This method system has been applied to the environmental risk assessment and regulatory rating of eight water sources along the Nanjing Yangtze River, with excellent achievements. As the results reveal, eight water sources suffer 437 risk impacts from 175 risk sources, 69.04% of which are low-risk impacts and 13 are high-risk impacts. Longtan water source suffers the most risk impacts of 86, among which eight are high-risk impacts. The impacts of multiply-risk sources on the eight water sources are high-risk impacts. The impact index of multiple risk sources increases from the upstream water sources to the downstream water sources, reaching the maximum value of 5.267 at the most downstream Longtan water source. Though the environmental risk and supervision rating of Longtan water source is high, those of other water sources are rated as medium.

Highlights

This paper proposes a methodology for determining the environmental risk and regulatory rating of water sources which considers the risk impact of the concentrated distribution of surrounding multiple risk sources on water source
The system comprises: (1) Considering the risk degree of risk sources and the position of risk sources relative to water sources, this paper proposes the risk impact degree of a single risk source on the water source, namely the calculation method of SrsRI. (2) Comprehensively considering factors such as SrsRI, means the risk sources quantity index (MrsQI), and RDIMrs, the paper puts forward the risk impact of the aggregation distribution of multiple risk sources on water sources, namely the calculation method of MrsRI. (3) By investigating the natural conditions, regulatory ability and emergency capacity of water sources, this study utilizes the index evaluation method to determine the anti-risk ability of water sources, and determines the importance of water sources through considering the factors like water supply and service population of water sources
(4) the environmental risk level and regulatory rating of water sources can be determined by comprehensively considering the multiple risk sources impact, anti-risk ability, and the importance of water sources

Summary

Introduction

The water pollution accidents of water sources in China happen frequently [1,2], and the security situation of water supply is more and more serious, which are mainly triggered by the continuous increase of fixed risk sources (hereinafter referred to risk sources) of the surrounding industrial enterprises, sewage treatment plants, and docks with the economic development. Sustainability 2021, 13, 1484 to prevent water pollution accidents in water sources, the research on risk assessment of water sources has attracted increasing attention of Chinese scholars and policy makers. Taking the drug concentration in water as the object, Houtman et al [4] assessed the health risks of drinking water from three water plants in 2014 based on the two-year monitoring data of raw water from Rhine River, Meuse River, and Polder River in Netherlands. Ahmad et al [5] assessed the radon activity concentration and toxic elements in the drinking water source in Sungai Petani City, Kedah, Malaysia

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