典型铅锌矿区周边土壤-稻米重金属污染特征及健康风险评价

Heavy Metals Contamination and Health Risks of Soil-Rice System in Typical Lead-Zinc Mining Area

为了掌握黔西北典型铅锌矿区周边稻田土壤重金属污染状况,分别采集98个土壤样品和稻米样品,运用单因子污染指数法、内梅罗综合污染指数法和潜在生态危害指数法对研究区稻田土壤中八种重金属(Cr、Ni、Cu、Zn、Cd、Pb、Hg、As)进行污染特征分析和风险评价,并采用健康风险评估模型对研究区稻米进行健康风险评价。结果表明:研究区稻田土壤受到重金属不同程度污染,整体处于中度污染水平(P_(N)=2.61),但Cu为重度污染(P_(Cu)=3.13);土壤生态风险总体处于中等水平(RI=279),最主要生态风险因子为Hg,其生态风险危害程度为很强(E_(Hg)=179);研究区稻米中重金属平均含量未超标,但有部分点位样品重金属含量超标;食用研究区种植的稻米不会对成人和儿童引起单一重金属健康风险,但长期食用,多种重金属复合污染会对成人和儿童健康产生负面影响(THQ_(成人)=2.41,THQ_(儿童)=2.48)。

In order to reveal the heavy metal pollution status of rice soil around typical lead-zinc mining area in northwest Guizhou,98 paired soil-rice samples were collected.The pollution risk of eight heavy metals(Cr,Ni,Cu,Zn,Cd,Pb,Hg and As)in rice soil from the study area was evaluated by single factor pollution index,nemero comprehensive pollution index and potential ecological hazard index,and the health risk assessment model was used to evaluate the health risk of rice in the study area.The results showed that rice soil was polluted by heavy metals in different degrees,the overall soil pollution was moderate(P_(N)=2.61),Cu was heavily polluted(P_(Cu)=3.13).The overall ecological risk of soil was at medium level(RI=279),the main ecological risk factor was Hg,which has a strong degree of ecological risk harm(E_(Hg)=179).The average content of heavy metals in rice did not exceed the evaluation standard,but the content of heavy metals in some sampling point exceeded the evaluation standard.The results of health risk assessment showed that the consumption of rice does not cause a single heavy metal health risk to adults and children,but long-term consumption of rice growing in the study area had a high possibility of causing multiple heavy metal composite pollution to adults and children(THQ_(adult)=2.41,THQ_(children)=2.48).