矿区周围稻米重金属积累及健康风险分析

Accumulation of Heavy Metals in Rice Growing Around Mining Area and Its Human Health Risk Analysis

选用杂交稻、常规稻和糯稻3个水稻品系共21个水稻品种在广东大宝山矿区周围重金属污染土壤中进行大田试验,研究Cu、Zn、Pb、As和Cd 5种重金属元素在不同水稻品种(品系)稻米中的积累状况,并进行健康风险评价分析。结果表明,供试水稻稻米中Cd和Pb超标率很高,分别为100%和71.43%;Cu和As超标现象不严重,超标率分别为4.76%和14.29%;Zn含量均不超标。供试水稻品系中常规稻和糯稻稻米对Cu、Zn、Pb、Cd的积累能力较高,杂交稻则较低;但杂交稻稻米对As的积累能力高于其他2个品系。稻米中Cu、Zn、Pb、As和Cd含量与稻谷生物量均呈负相关关系,其中Pb含量与稻谷生物量呈显著负相关。供试水稻稻米对5种重金属的富集能力由高到低排序为Cd>Zn>Cu>As>Pb。本研究表明供试土壤中Cd和Pb对人体健康存在比较严重的潜在威胁,Cu、Zn和As对人体健康的潜在危害较小,应重点关注大宝山矿区稻米Cd和Pb的重金属污染问题及其对人体健康的潜在危害。

Accumulation of Cu, Zn, Pb, As and Cd in rice of 21 cultivars, including hybrid, conventional and glutinous rice, was studied through a field experiment laid out in the paddy fields around the Dabaoshan Mining Area in Guangdong Province and its human health risks are analyzed. Results show that in accordance with the criteria in the China National Hygienic Standard for Food, the over-limit rate of Cd and Pb in rice was very high, being 100% and 71.43% , respectively, whereas that of Cu and As was only 4. 76% and 14. 29% higher, respectively, and that of Zn negative. Among the cultivars, conventional and glutinous rices were more capable of accumulating Cu, Zn, Pb and Cd, while hybrid rice more of accumulating As. Negative relationships were observed between the concentrations of Cu, Zn, Pb, As and Cd in rice grains and the biomass of the whole plant. In terms of plant accumulation of the five metals by the rice cultivars in the experiment, they followed the the sequence of Cd〉Zn〉Cu〉As〉Pb. The findings of the research indicate that Cd and Pb in the soil of the experiment posed serious potential health risks, where Cu, Zn and As minor ones. It is, therefore, essential to pay high attention to the issue of Cd and Pb pollution of rice produced in the Dabaoshan Mining Area and its associated potential risk to human health of the rice consumers.