都柳江上游沿岸喀斯特地区土壤重金属污染及健康风险分析

Soil heavy metal pollution analysis and health risk assessment in Karst areas along the upper reaches of the Du Liujiang River

以贵州省都柳江上游沿岸喀斯特地区为研究对象,根据空间系统法布设样点,共采集62个表层土壤样品.运用单因子污染指数法、内梅罗综合污染指数法、人体健康风险评价模型、克里金插值方法和地理探测器模型,研究土壤重金属Sb、As、Cd、Pb和Cu的污染及人体健康风险空间分布特征.结果表明,研究区土壤Sb和Cd含量分别是贵州省土壤重金属背景值的6.58和1.95倍.土壤重金属总体属于轻度污染,土壤Sb和As的轻度及以上污染面积分别占总面积的24.62%和20.97%,Cd轻度污染面积分布最广,占总面积的44.55%.研究区土壤重金属人体健康风险为低风险等级,儿童健康风险大于成人,Cd和Sb是人体健康风险的主要影响元素.由地理探测器分析可知,所有因子中地层对土壤中Sb和Cd人体健康风险空间分异的解释力最大,其余因子对土壤Cd的人体健康风险空间分异解释力大小依次为:土壤类型>海拔>距河流远近>土地利用类型>坡度;而其余单一因子对土壤中Sb人体健康风险空间分异的解释力均较低,其空间分异可能受到多重因子的复合影响.地层与Cd对成人和儿童的致癌健康风险呈显著正相关(p<0.05),相关系数为0.63,地层与Sb对成人和儿童的非致癌健康风险呈显著正相关(p<0.05),相关系数为0.43.Cd的最高人体健康风险概率主要分布在独山组和龙洞水组及邦寨组,Sb的最高人体健康风险概率主要分布在石牛栏组和邦寨组.因此,研究区内石牛栏组、邦寨组和独山组地层是该区域土壤重金属健康风险的重点防控对象.

In the present study,the karst area along the upper reaches of the Du Liujiang River in Guizhou Province was taken as the study object,62 surface soil samples were collected according to the spatial system method.The single factor index method,the Nemero comprehensive index method,the human health risk assessment model,the Kriging interpolation method and the geographic probe model were used to estimate the pollution characteristics and human health risks of soil heavy metals(Sb、As、Cd、Pb and Cu).The results showed that Contents of Sb and Cd in soil were separately 6.58 and 1.95 times than the background values.The soil total contamination levels were mid pollution,and 24.62%and 20.97%of the the study area suffered from mild or above pollution separately with Sb and As.44.55%of the study area suffered from mild pollution with Cd.The human health risk of soil heavy metals in the study area was low,which for children is greater than that for adults.Cd and Sb are the main elements affecting health risk.The geographical detector analysis showed that strata was the dominant factors affecting the spatial differentiation of human health risk for Sb and Cd.The explanatory power of other factors on the spatial differentiation of human health risk for soil Cd was as follows:soil type>altitude>distance from river>land use type>slope;the single factor had a low explanatory power for the spatial variation of human health risk for Sb in soil,and the spatial variation may be influenced by multiple factors.The strata was positively associated with health risk of Cd and Sb,with a significant positive association with carcinogenic health risk of Cd adults and children(p<0.05),the correlation coefficient was 0.63 and a positive association with non-carcinogenic health risk in adults and children of Sb,the correlation coefficient of 0.43.The maximum risk probability of human health risk for Cd were mainly in the Dushan Group,Longdongshui Group and Bangzhai Group,and the highest probability of health risk for Sb were mainly in the Shiniulan Group and Bangzhai Group.Therefore,the Shiniulan,Bangzhai and Dushan Formation in the study area are proposed as the key protection targets of soil heavy metal pollution and health risks.