铜仁市土壤-玉米重金属含量及其健康风险

为了解铜仁市玉米地土壤和玉米籽粒重金属的含量分布特征,并评估当地居民通过玉米籽粒摄入重金属的健康风险.于2018年7月采集了铜仁市自然土壤样品65个、玉米地土壤样品122个和玉米样品100个,并分析其Cd、Pb、Cu、Zn、Ni、As、Hg含量,通过重金属摄入量评价居民膳食暴露的健康风险.结果表明,自然土壤Cd、Pb、Cu、Zn、Ni、As和Hg的含量均值分别为0.148、23.09、29.60、103.6、37.73、16.43、0.144 mg·kg^-1;玉米地土壤Cd、Pb、Cu、Zn、Ni、As和Hg的含量均值分别为0.273、30.00、27.79、103.4、29.89、13.58、1.037 mg·kg^-1.以《土壤环境质量农用地土壤污染风险管控标准》(GB 15618—2018)中的风险筛选值作为限量标准,玉米地土壤Cd、As和Hg超标率分别为18.9%、19.7%和17.2%;以风险管制值为限量标准,玉米地土壤Hg超标率为10.7%.依据GB 2762—2017《食品中污染物限量》,玉米籽粒Cd和Pb超标率分别为7.0%和44%.人体健康风险评价表明,居民通过食用玉米籽粒的重金属健康风险THQ值均小于1,表明食用当地玉米对居民的健康不会造成明显影响.

Concentrations and health risk assessments of heavy metal contents in soil-corn system of Tongren,China

In order to understand the distribution of heavy metal in soil-corn system of Tongren City and evaluate the health risk of the exposure of typical local residents to heavy metals through consumption of corn. A total of 65 natural soil samples,122 soil samples from corn fields and 100 corn samples were collected in July 2018 and then analysis the contents of Cd, Pb, Cu, Zn, Ni, As and Hg. And furthermore, the potential health risk of the dietary exposure of residents was assessed through the intake of heavy metals. Results showed that the mean contents of Cd, Pb, Cu, Zn, Ni, As and Hg in the natural soil samples were 0.148, 23.09, 29.60, 103.6, 37.73, 16.43 and 0.144 mg·kg^-1;the mean contents of Cd, Pb, Cu, Zn, Ni, As and Hg in the soil samples from corn fields were 0.273, 30.00, 27.79, 103.4, 29.89, 13.58 and 1.037 mg·kg^-1. The over-standard rate of Cd, As and Hg in soil samples from corn fields was calculated to be 18.9%, 19.7% and 17.2% respectively, by risk screening values for soil contamination of GB 15618—2018 "Risk control standard for soil contamination of agricultural land". The over-standard rate of Hg in soil samples from corn fields was calculated to be 10.7%, by risk intervention values for soil contamination. The over-standard rate of Cd and Pb in corn samples was calculated to be 7.0% and 44%, by GB 2762—2017 "Thresholds for pollutants in food". Human health risk assessment showed that the THQ of heavy metals of corn was below 1, which indicate that ingestion of locally produced corn would not have any significant health risk.