贵州油茶主产区土壤重金属环境质量状况及风险评价

Pollution and risk assessment of heavy metals in camellia oleifera main producing area soil of Guizhou Province

为评价重金属污染对油茶籽油质量安全的影响,分析了贵州省油茶产地256份土壤样品中重金属元素Pb、Cd、Hg、As、Cu和Cr的含量,并采用地积累指数法、潜在生态危害指数法和健康风险评价模型对土壤重金属污染进行风险评价.结果表明,Pb、Cd、Hg、As和Cu含量超过贵州土壤背景值占比大于50%以上,Cr约10%的样点超过背景值.土壤中Cd和Hg含量超过管制值(GB 15618-2018)的样点分别占总样点的13.9%和0.39%,Pb、As、Cu和Cr含量无超过管制值的样点.地积累指数法评价结果表明,产区土壤主要受Cd、Hg的污染,污染程度主要为轻度和中度污染,样点占比分别为33.6%和38.68%,而Pb、As、Cu轻度和中度污染占比均低于6%.Cd和Hg在综合潜在生态指数中占比最重,对综合生态风险平均贡献率分别为30.84%和56.35%.综合生态风险中轻微、中等、重度、强烈污染程度的样点分别占总样点数的33.59%、40.63%、16.80%、8.98%.重金属对儿童的非致癌风险高于成人,成人和儿童综合非致癌风险(THI)分别为0.795、4.82,综合致癌风险(TCR)分别为1.58×10^(−5)、6.56×10^(−5),儿童的非致癌风险主要由As贡献,致癌风险主要由As和Cr贡献,致癌风险对于成人和儿童整体处在可接受水平.

To evaluate the influence of heavy metal pollution on the quality and safety of camellia oleosa seed oil,the characteristic of heavy metal pollution and health risks of heavy metals in main production areas of Camellia oleifera soil in Guizhou were studied in this paper.Pb,Cd,Hg,As,Cu and Cr were detected from 256 soil samples,and the data were assessed by geoaccumulation Index,potential ecological risk index and health risk assessment model.The result show that the content of Pb,Cd,Hg,As and Cu exceeded the background value of Guizhou soil by more than 50%,and Cr content exceeded the background value about 10%.The samples of Cd and Hg were greater than the control value of soil pollution risk for agricultrural land(GB 15618-2018)accounted for 13.9%and 0.39%of the total samples,respectively,while no samples with Pb,As,Cu and Cr content exceeding the control value.The evaluation results of geoaccumulation Index show that the soil in the producing areas was mainly polluted by Cd and Hg,and the pollution degree was mainly mild and moderate,with samples accounting for 33.6%and 38.68%,respectively,while the proportion of Pb,As and Cu was less than 6%,respectively.Cd and Hg contributed 30.84%and 56.35%to the comprehensive ecological risk on average,respectively.The samples with mild,moderate,severe and strong pollution levels accounted for 33.59%,40.63%,16.80%and 8.98%of total samples,respectively.Health risk assessment show that the non-carcinogenic risk of children was higher than of adults,the comprehensive non-carcinogenic risk index(THI)of heavy metal to adults and children was 0.795 and 4.82,respectively,and comprehensive carcinogenic risk index(TCR)was1.58×10^(−5),6.56×10^(−5),respectively.The non-carcinogenic risk higher for children was mainly contributed by As,while carcinogenic risk was mainly contributed by As and Cr,the carcinogenic risk is acceptable for adults and children as a whole.