江心洲水陆交错带土壤重金属污染特征及风险评价

Contamination characteristics and risk assessment of heavy metals in soil of aquatic-terrestrial ecotone of central bar in the Yangtze river

选取长江安徽段8个江心洲为研究对象,采用人体健康风险评价等多种方法对江心洲水陆交错带土壤重金属Cd、Pb、Cu、Zn的污染特征及风险进行了评价。结果表明:研究区土壤整体呈弱碱性;以GB15618—2018为标准,重金属Cd有53%的样品超过农用地土壤污染风险筛选值,污染最为严重,其他元素均未超过筛选值;单因子、内梅罗和地积累指数法评价显示除Cd外,其他3种重金属呈现无污染的清洁状态;潜在生态风险指数介于4.32~442.09之间,呈现轻微潜在生态风险水平;Cd的人体健康致癌风险呈有风险但处于可接受水平,对儿童的健康风险水平均高于成人,同时4种重金属针对于成人与儿童的总非致癌风险值HI均远小于1,表明其对人体的健康风险较小或可忽略。

This study selected eight central bar of the Yangtze River in Anhui section as the research object,the pollution characteristics and risks of heavy metals Cd,Pb,Cu and Zn in the soil of aquatic-terrestrial ecotone of central bar were evaluated by various methods such as human health risk assessment.The results showed that:the soil in the study area presented weakly alkaline;according to the standard of GB15618-2018,53% of the heavy metal Cd samples exceeded the soil pollution risk screening value of agricultural land,which was the most serious contamination,while all the other elements did not exceed the screening values;single factor,Nemero and ground accumulation index methods showed that except for Cd,the other three heavy metals were clean;the potential ecological risk index was between 4.32 and 442.09,showing a slight potential ecological risk level;the carcinogenic risk of Cd was risky but at an acceptable level,and the health risk of children was higher than that of adults,while the total non-carcinogenic risk value of four heavy metals for both adults and children was much less than 1,indicating that the health risk was small or negligible.