区域小麦籽粒重金属分布及暴露评估

Spatial Distribution of Heavy Metal in Wheat Kernal and Dietary Exposure Assessment of Local Residents in an Industrial Area

以某冶金和电厂工业园为研究区域,采集90份小麦籽粒样品,用ICP-MS测定铅、镉元素含量,应用普通克里金法预测小麦籽粒铅、镉含量空间分布;用目标危害系数(THQ)法评估其食用安全性,以及当地居民铅、镉暴露风险。以明确区域小麦籽粒重金属铅、镉污染水平及分布,评估当地居民铅、镉暴露风险。结果表明,该区域小麦籽粒铅、镉超过国家限量标准(GB 2762—2012)的比例为68.6%和34.3%;随着距铅锌冶炼厂距离的增加,铅、镉含量逐渐下降,距铅锌冶炼厂东南侧约l km范围内的小麦籽粒铅、镉含量最高;成人和儿童经小麦全粉摄入铅暴露风险均大于1(THQ_(成人)=1.05,THQ_(儿童)=1.35),成人和儿童经小麦全粉摄入镉暴露风险均小于1(THQ_(成人)=0.72,THQ_(儿童)=0.92)。该区域小麦籽粒已受到一定程度铅、镉污染。铅、镉含量空间分布图表明铅锌冶炼厂是小麦铅、镉污染的重要来源。成人和儿童经小麦摄入铅暴露风险均达到不可接受的水平,且儿童铅暴露风险大于成人;成人和儿童镉暴露风险均在可接受的水平。

This study is based on one of the metallurgical and Power Plant Industrial Park as the study area. A total of 90 wheat kernel samples were collected. Pb and Cd concentrations were measured by inductively plasma mass spectrom- etry （ICP - MS）. The spatial distribution of heavy metal concentration in wheat kernel was predicted by Ordinary Krigging methods. The edible safety of wheat and dietary exposure risk of local residents were assessed by Target Hazard Quentient （THQ）. In order to explore the level of Pb and Cd contamination in wheat kernel in the studied area, the health risk of lo- cal residents via dietary lab and Cd exposure were assessed. The results showed that the concentration of Pb （68.6%） and Cd （34.3%） in the wheat samples exceeded maximum permissible levels （GB 2762--2012）. The concentration of Pb and Cd proved to be significantly higher within 1 000 m in the southeast of the smelter. The concentration of Pb and Cd in wheat decreased gradually with distance from the smelter. The THQ of Pb estimated merely for wheat was 1.05 and 1.35 for adults and children, while the THQ of Cd was 0.72 and 0. 92 for adults and children, respectively. The wheat kernel in the studied area was polluted to some extent. The results of spatial distribution of Pb and Cd concentrations in wheat kernel in the studied area indicated that the smelter was the main source of heavy metal contamination of wheat. The risk exposure to Pb of local inhabitants via consumption of wheat could not be accepted. The risk for children was greater than adults. The risk exposure to Cd of local inhabitants via consumption of wheat could be accepted.