珠江三角洲平原广东省佛山市顺德区土壤-蔬菜系统中Pb的健康安全预测预警

Prediction and early-warning for health safety of lead in soil and vegetable system,the Pearl River Delta Plain,southern China

分析珠江三角洲顺德区208个蔬菜地表层土样、114个蔬菜样Pb的全量和38个表层土样Pb的形态含量,结果表明,土壤Pb平均值为44.3mg/kg,77.5%的土壤Pb含量超过广东省土壤背景值,蔬菜Pb超标率为74.6%。用2007年蔬菜土壤Pb的累积速率(1.02mg/kg),预测未来10年土壤Pb含量变化趋势,并分别以150、270、300和8580(mg/kg)为阈值对土壤中Pb进行预警,2007—2017年超过150mg/kg的土壤面积比例有所增加,而超过270mg/kg、300mg/kg的土壤面积比例不变。蔬菜Pb与土壤Pb的全量或有效量之间均存在"高原模式"。蔬菜Pb的空间分布表明,3种蔬菜Pb的高浓度主要位于工业比较发达的城镇,这与土壤Pb的空间分布大体一致。经蔬菜途径吸收Pb的THQ靶标危害系数不超过0.4。不同区域、家庭经济收入水平的THQ排序:THQ高>THQ城市>THQ中>THQ农村>THQ低,表明经济收入水平高的家庭经蔬菜途径摄入Pb的健康风险最高。

In Shunde District of Foshan City,Pearl River Delta Economic Zone,208 topsoil samples and 114 vegetable samples were collected from vegetable fields to measure the contents of lead （Pb） ,which species of 38 topsoil samples were extracted.The results showed that the average concentration of heavy metal Pb was 44.3mg/kg.The contents of soil lead that exceeded Guangdong Province soil background values accounted for 77.5%,,the content of lead in vegetable that exceeded safety requirements for non-en-vironmental pollution vegetable accounted for 74.6%.The accumulation tendency of soil Pb of study area in the future 10 years was predicted based on the accumulation rate of soil Pb in 2007 which equaled to 1.02mg/kg.Early-warning for the accumulation tendency of soil Pb were done based on the threshold values 150、270、300 and 8580mg/kg,respectively.The scale which soil Pb in excess of 150mg/kg was increased during 2007-2017 years,however,the scales were increased,which soil Pb in excess of 270、300mg/ kg,respectively.There was a significant relation between the transfer factor values and the corresponding soil Pb concentrations （full dosage or bioavailable amount）,which can be described by a plateau model.The target hazard quotients （THQs） can be used to evaluate the health risks with heavy metals by consuming vegetable.The THQs of Pb in vegetables were below 0.4 that values from large to small were THQhighTHQurban THQmedian THQruralTHQlow,which indicated that the health risk via vegetable consumption in the high levels of family economic income was the highest.Moreover,further researches about influence of Pb on the human health through other exposure paths should be done.