南方典型镉污染地区土壤-农产品镉含量与人群健康风险评估

Concentrations of Cd in Soil and Corresponding Crop and Vegetable and Population Health Risk Assessment from a Typical Cd-contaminated Area in South China

选取南方某典型镉污染地区,在县级行政区域尺度上采集了200对土壤-水稻和142对土壤-蔬菜样品,分析了土壤理化性质以及镉在农产品和土壤中的全量。结果表明,土壤镉含量在0.04~8.20 mg/kg,均值0.83 mg/kg,中位值0.54 mg/kg,其中55%的样品超过我国农用地土壤污染风险筛选值;稻米镉(干重)含量在0.02~2.61 mg/kg,均值0.37 mg/kg,中位值0.44 mg/kg,超标率为54%;蔬菜镉(鲜重)含量在0.01~1.28 mg/kg,超标率为29%。结合膳食数据评估了当地居民膳食镉摄入情况,计算表明,当地居民通过食用自产稻米与蔬菜,日均膳食摄入镉的量为2.98~5.19μg/kg BW,是联合国粮农组织/世界卫生组织食品添加剂联合专家委员会(JECFA)推荐值(每月耐受摄入量为25μg/kg BW,每月以30 d计,日均耐受摄入量为0.83μg/kg BW)的3.58~6.23倍。儿童(4~11岁)因单位体重摄入的食物量较高,产生的暴露风险高,日均镉摄入量高达5.19μg/kg BW,是JECFA限量值的6.23倍。因此,亟需采取行动降低当地人群的镉暴露风险。

Concentrations of Cd in farmland soil and corresponding crop and vegetable from a typical Cd-contaminated area in southern of China were investigated.A total of 200 pairs of soil-rice samples and 142 pairs of soil-vegetable samples were collected at the county administrative district scale to analyze physiochemical properties of soil and total concentration of Cd in farm products and soils.Among the 342 soil samples,Cd concentration in soil ranges from 0.04 to 8.20 mg/kg,with mean value of 0.83 mg/kg and median of 0.54 mg/kg.In comparison to the risk screening values for soil contamination of agricultural land,standard exceeding ratios of 55%for Cd in soil is identified.Cd concentrations in rice samples varies from 0.02 to 2.61 mg/kg,with mean value of 0.37 mg/kg and median of 0.44 mg/kg,leading to approximately 54%of the rice samples exceeds the Chinese maximum permissible limit,while those in vegetables are in range of 0.01 to 1.28 mg/kg fresh weight(FW),with mean value of 0.17 mg/kg FW and median of 0.08 mg/kg FW,result in a standard exceeding ratio of 29%.Based on Cd concentrations in dietary items and amounts of consumption,it is estimated that mean dietary intake of Cd varies from 2.98 to 5.19μg/kg BW per day,representing 3.58—6.23 times of the tolerable dietary intake of 25μg/kg BW per month recommended by JECFA.Among the subgroups,children exhibit the highest dietary Cd intake dose of 5.19μg/kg BW per day,which is 5.19 times the recommended tolerable intake by JECFA.Therefore,actions are urgently needed to reduce the risk of high Cd exposure for the local residents.