【摘要】 以福建省某矿区为例,研究矿区周边土壤-农作物中重金属的空间变异特征及其健康风险,以期为土壤重金属污染治理和农作物质量安全提供参考依据。在分析土壤和农作物中7种重金属(Pb、Cd、Cr、Cu、Zn、Ni、As)的全量和有效态含量统计特征的基础上,应用地统计学中半方差函数和反距离权重插值法探讨7种重金属全量和有效态含量的空间变异规律和分布情况,并结合健康风险评价模型评价由于农产品摄入导致的人体健康风险。结果表明:土壤全量Pb、Cd、Cr、Cu、Zn、Ni、As超标率分别为88.89%、91.11%、0、73.33%、82.22%、2.22%、0(国家标准GB 15618—2018);有效Pb、Cd、Cr、Cu、Zn、Ni、As的超标率分别为100%、68.89%、48.89%、6.67%、24.44%、22.22%、40.00%(福建省地方标准DB 35/T 859—2016);除Cr和Ni,其他元素的全量和有效态含量均显著正相关;CEC与Cd、Zn、Ni有效态含量显著正相关,pH与Ni和Cd有效态含量显著负相关,有机质与Cu和Ni有效态含量显著正相关,游离Fe2O3与Zn有效态含量显著正相关。由块金系数可知,全Pb、全Cd、有效Cd、全Cr、有效Cr、全Cu、有效Zn、全Ni、全As、有效As均小于25%,具有强空间关系,其余元素在25%～75%之间,具有中等相关性;从单一目标危害目标危险系数(THQ)来看,儿童叶菜类Cd的THQ>1,且总体高于成人,说明儿童对各种重金属更为敏感;成人和儿童的薯类和叶菜类的总THQ>1,说明研究区存在明显的复合健康风险。该矿区土壤重金属存在较强的空间关系,且其农产品具有一定的健康风险。更多还原

【Abstract】 To reveal the cumulative characteristics of heavy metal elements and the crop safety around mining areas, geostatistical analysis methods, such as semi-variogram and inverse distance weight interpolation, and a health risk assessment model were employed in this study. The former computed the spatial variability and distribution of heavy metal elements, and the latter estimated the health risk induced by crop intake. Seven heavy metal elements in a mining area of the Fujian Province were sampled and detected, specifically Pb, Cd, Cr, Cu,Zn, Ni, and As, and the over-standard rates of their total content were 88.89%, 91.11%, 0, 73.33%, 82.22%, 2.22%, and 0, respectively,according to national standards GB 15618—2018, while the over-standard rates of their available content were 100%, 68.89%, 48.89%,6.67%, 24.44%, 22.22%, and 40.00%, respectively, according to Fujian provincial local standards(DB 35/T 859—2016). In this study,the total content and available content of each heavy metal element had a significantly positive correlation, except for Cr and Ni. The potential hydrogen(pH)negatively influenced available Ni and Cd, while cation exchange capacity(CEC)had a positive influence on available Cd, Zn, and Ni. The effects of soil organic matter content on available Cu and Ni were positive, as well as the effect of free ferric oxide on available Zn. The results of geostatistical analysis determined that the total and available content of heavy metal elements were spatially autocorrelated due to nugget coefficients of less than 75%, where total Pb, total Cd, available Cd, total Cr, available Cr, total Cu, available Zn,total Ni, total As, and available As held stronger spatial autocorrelations according to nugget coefficients of less than 25%. The results of the health risk assessment demonstrated that the total target hazard quotient(TTHQ)of tuberous vegetables and leafy vegetables was greater than 1, which meaned that the study area was significantly threatened by compounding health risks. Moreover, children were more sensitive to various heavy metals than adults due to the target hazard quotient(THQ)of Cd in leafy vegetables, which was greater than 1. The heavy metal elements in this mining area were spatially autocorrelated, and crop safety hardly met the requirements for human health.更多还原