工业区土壤和农产品镉污染状况及暴露评估

以某铅锌冶炼厂周边为研究区域,网格法采集30个表层(0～10 cm)土壤样品,对应采集46个粮食样品和69个蔬菜样品,用ICP-MS测定镉质量比。运用普通克里格法(Ordinary Krigging)预测研究区域内土壤镉质量比的空间分布,结合单因子污染指数评价土壤的镉污染级别。通过分析粮食和蔬菜的镉质量比,评估其食用安全性以及受调查居民镉的膳食暴露风险。结果表明:1)距离铅锌冶炼厂1 000m范围,或东南侧(下风向)3 000 m内土壤中镉质量比大于0.65mg.kg-1;2)研究区域土壤中镉单因子污染指数超过了警戒线(P≥1.0),个别区域受到严重污染(P=4.7);3)土壤与小麦籽粒镉质量比存在极显著正相关关系(r=0.889,p<0.01),粮食样品镉质量比超过限量标准(GB 2762—2005)的占52.2%,蔬菜样品为8.7%;4)仅以粮食和蔬菜摄入估计的THQ=0.79,对于普通人群来说,小麦、蔬菜和大豆摄入对每日镉摄入量的贡献率分别为85.1%、12.9%和2.0%。研究区域土壤2/3以上面积受到镉污染,土壤可能是小麦籽粒镉的来源之一。当地受调查人群若长期食用该地区种植的农产品,镉的膳食暴露风险在可接受的范围内,其中,小麦对镉摄入贡献最大。

Cadmium contamination and exposure assessment in the soil, food and dietary in an industrial area

The present paper deals with the cadmium contamination and the exposure assessment in the soil, food and dietary in an industrial area so as to explore the extent and level of Cd contamination in the above said food products and in the soil of an industrial area, the health risk of local residents via dietary Cd exposure. The total of 30 surface soil samples (0-10 cm) and the corresponding 46 grain samples and 69 vegetable samples have been collected in the vicinity of a lead-zinc smelting plant. In proceeding with our research, we have measured the Cd pollutant concentrations in the samples by using the inductive plasma mass spectrometry (ICP-MS) and checked the spatial distribution of Cd concentrations in the soil by ordinary Krigging assessment method trying to provide an assessment of the contamination level of the soil with the indices of each single factor in the research area. Through the analysis on Cd concentrations of grains and vegetables, we have assessed the edible safety and the investigation of local residents on the dietary exposure hazards. The results of our investigation can be stated as follows: (1) The contamination concentrations of Cd prove to be significantly higher(0.65 mg·kg-1) in the soils within 1 000 m or 3 000 m in the southeast of the smelter; (2) Indices of single factor of Cd exceeded the alarming line (P≥1.0) and some samples were found even more seriously polluted (P=4.7); (3) The Cd concentration of the soil turns to be significant positive related with the wheat kernel. The concentrations of Cd in 52.2% of the grain samples collected and in 8.7% vegetable samples collected prove to be over the maximum tolerable levels (GB 2762—2005); (4) The THQ of Cd estimated merely by grain and vegetables remains 0.79. Therefore, for the ordinary people, from the point of view of the Cd condemnation, or the daily intake of Cd, the contribution of grains, vegetables and soybeans was respectively about 85.1%, 12.9% and 2.0%. Over 2/3 of the soil under study (the soil maybe one of the Cd pollution sources of wheat kernel) can be considered slightly contaminated by Cd. However, from the long term of view, if the local people consume the agro-food products, the dietary exposure hazard is still to be tolerable, though the largest contribution to wheat was the intake of Cd.