Water Environment Quality Analysis And Potential Risk Assessment In Chengde Region

Chengde area is an important barrier for water resources security and ecological environment security in Beijing,Tianjin and Hebei.However,the mining industry in this area has developed rapidly,and the amount of solid waste produced by mineral activities is relatively large,which may cause potential harm to the surrounding water environment.This thesis studies the water environment quality status of the main water system in Chengde area,constructs the regional water environment risk evaluation model,and evaluates the potential risk of the water environment in Chengde area.According to the spatial and temporal concentration change analysis of each water quality index in the monitored section,the permanganate index,total phosphorus and chemical oxygen demand have a great impact on the water environmental quality,the dissolved oxygen,ammonia nitrogen and five-day biochemical oxygen demand have less impact,and the impact of copper,zinc and fluoride is negligible.Single factor evaluation method,comprehensive pollution index method and principal component analysis method are used.The evaluation results show that in terms of time,the water quality in 2019 and 2020 is significantly improved compared with 2017 and 2018,and the pollution of Gong and Chenggang Bridge is relatively serious.The proportion of single-factor evaluation results from categories I to inferior V sections was 8.62%,54.31%,25.86%,7.76%,2.59% and 0.86%,respectively.The proportion of the comprehensive pollution index category I ～ section accounted for 3.44%,44.84%,44.84% and 6.88%,respectively,and the average sharing rates of chemical oxygen demand,permanganate index,five-day biochemical oxygen demand,total phosphorus and ammonia nitrogen were 28.45%,24.33%,21.25%,17.39% and 8.58%,respectively.The principal component analysis showed that the water quality was mainly affected by the total phosphorus,chemical oxygen demand and permanganate index.On the whole,the water quality of the main water system in Chengde is good from 2017 to 2020.Select 15 water environment risk assessment indexes,social economy includes GDP per capita,urbanization rate,population growth rate,per capita disposable income of rural residents and urban residents;water resources,water environment includes annual precipitation,per capita,per capita water consumption,per capita water consumption,total phosphorus rate,surface water permanganate index and chemical oxygen demand of surface water;mineral solid waste includes annual concentrate production,existing proportion of tailings and tailings reservoir capacity.The risk is divided into five levels: major risk,high risk,medium risk,low risk,and very low risk.The weight of each index was calculated by hierarchical analysis method,and the weight of social and economic risk,water environment risk and mineral solid waste risk were 10.47%,63.7% and 25.83%,respectively.The water environment risk in Chengde area was evaluated,and the water environment risk index in Shuangluan District was2.14,respectively,which was a medium risk area.Other areas are all low-risk areas.On the whole,The water environment risk in Chengde area is relatively small..