Study on the Spatiotemporal Distribution and Health Risk Assessment of Heavy Metals in the Surface Water of Ya'an City
In order to analyze the spatiotemporal distribution and health risks of heavy metals in the main surface rivers of Ya'an City,Dadu River and Qingyi River,the health risk assessment model recommended by the USEPA was used to evaluate the health risks caused by exposure to drinking water and skin contact routes.From January to December 2022,water samples from 12 monitoring points in the main and tributaries of the Dadu River and Qingyi River were analyzed and tested monthly.The average content of heavy metals Cu,Zn,Cd,Pb,and Cr in the surface water rivers of Ya'an City was 0.83,2.21,0.96,0.09,and not detected(μg/L),respectively.The surface water throughout the year had reached the Class II standard limit;From the perspective of spatial structure,the spatial distribution characteristics of heavy metal concentrations at each point were as follows Zn>Cu>Cd>Pb>Cr.From the perspective of coefficient of variation,the coefficient of variation of Cu,Zn,and Cd elements at some sampling points exceeded 1%.From the perspective of seasonal changes,the overall concentration of heavy metal elements Zn and Cu in surface water shows a higher trend in dry season than in wet season.The health risk assessment results indicate that the average annual health risks of adults and children caused by heavy metal elements in surface water through drinking water and skin contact pathways are lower than the internationally recommended negligible risk level(1.0×10-8/a),adults are higher than children,and the total health risk values of carcinogenic heavy metal Cd generated through drinking water for both adults and children are higher than the maximum acceptable risk level of 1.0×10-6/a.Cd is the element that contributes the most to overall health risks,and special attention needs to be paid to Cd pollution,as well as strengthening the supervision and control of heavy metal concentrations.
万方数据
维普
