Study On Environmental Risk Assessment Method For River-type Drinking Water Sources

Drinking water source is an important public infrastructure to ensure the safety of urban water supply and the normal operation of society.The safety of drinking water plays a vital role in people’s health and economic development.River-type water sources often suffer from large environmental risks because of the various industries on the riverside and also the river transportation function.Carrying out environmental risk assessment of drinking water sources and proposing risk prevention measures based on the evaluation results are of great significance for water source protection.Based on the vulnerability and potential risk of water sources,this paper analyzes the main factors leading to the occurrence of pollution accidents in river-type drinking water sources and eventually selects 27 risk assessment factors.This paper constructs the calculation model of environmental risk assessment of river-type drinking water sources.In this study,we take 97 river-type drinking water sources in the mainstream of the Yangtze River as an example,considering the various risks to calculate the environmental risk degree of each water source.The risk assessment results are classified into five categories,and risk prevention suggestions are proposed for each risk level.The main research results of this paper are as follows:(1)Constructing an environmental risk assessment model for river-type drinking water sources.The model includes water source vulnerability assessment and potential risk assessment.The vulnerability assessment model includes natural attributes,social attributes,and emergency response capabilities of cities.The potential risk assessment model includes chemical enterprises and the transportation situation of the river.(2)Vulnerability evaluation results of the case:Among the 97 river-type drinking water sources in the mainstream of the Yangtze River,12 are extremely low-vulnerability water sources,accounting for 12.4%;30 are low-vulnerability water sources,accounting for 30.9%;25 are medium-risk vulnerability water sources,accounting for 25.8%;17 are high-vulnerability water sources,accounting for 17.5%;13 are extremely high-vulnerable water sources,accounting for 13.4%.Due to the advantages of natural factors,the upstream water sources of the mainstream of the Yangtze River are significantly less fragile.(3)Potential risk assessment results of the case:33 are extremely low-risk water sources,accounting for 34.0%;35 are low-risk water sources,accounting for 36.1%;20 are medium-risk water sources,accounting for 20.6%;8 are high-risk water sources,accounting for 8.3%.There is one extremely high-risk water source,accounting for 1.0%.The water sources with higher risk are concentrated in the Chongqing city,Hubei province and Jiangsu province.(4)Environmental risk assessment results of the case:among the 97 drinking water sources in the mainstream of the Yangtze River,13 are extremely low-risk water sources,accounting for 13.4%;54 are low-risk water sources,accounting for 55.7%;25 are medium-risk water sources,accounting for 25.8%;and 5 are high-risk water sources,accounting for 5.1%;no extremely high-risk water source.On the whole,Jiangsu Province has a higher proportion of high-risk water sources than other provinces.(5)Proposing water source environmental risk prevention measures based on the results of risk assessment.According to the results of environmental risk classification,finding out the key points of risk prevention and control measures at each level.Through the analysis of vulnerability and potential risk,the corresponding risk prevention and control opinions are proposed.