2012—2014年台山市自产大米重金属污染情况

Heavy metals contamination of rice produced in Taishan City from 2012-2014

目的了解台山市生产的大米受重金属污染物污染的现况,为及时采取针对性预防措施和科学调整干预策略提供依据。方法 2012—2014年采集台山市18个乡镇农户家自产大米样品893份,按照GB 5009.12-2010、GB/T 5009.15-2003、GB/T 5009.11-2003及GB/T 5009.17-2003分别测定大米中铅、镉、无机砷和总汞含量。结果 2012—2014年在18个乡镇共检测台山产大米893份,在4种重金属中,铅的超标率最高,为2.24%;镉的超标率为0.67%,无机砷和汞均未超标。台山市大米的无机砷年风险值大于美国环境保护局推荐的1×10^(-4)/a的水平;镉年风险值大于瑞典环境保护局、英国皇家协会、荷兰建设和环境部推荐的1×10^(-6)/a的水平;铅年风险值小于荷兰建设和环境部推荐的可忽略风险水平1×10^(-7)/a;汞年风险值小于英国皇家协会推荐的可忽略风险水平1×10^(-8)/a。结论台山市区域内自产的大米重金属污染尚不算严重,但可以通过针对重金属污染的可能来源,采取科学、可行的干预措施,进一步降低无机砷和铅、镉的污染,将大米中重金属通过摄入途径对人体健康的潜在危害降到最低。

[Objective] To understand the current status of heavy metal contamination in rice in Taishan City,provide the scientific basis for taking preventive measures and adjusting intervention strategies.[Methods]893 rice samples were collected from 18 townships in Taishan City from 2012-2014. The contents of lead,cadmium,inorganic arsenic and total mercury in rice were measured according to GB 5009.12-2010,GB/T 5009.15-2003,GB/T 5009.11-2003 and GB/T 5009.17-2003,respectively.[Results]Totally 893 rice samples in Taishan were detected from 2012-2014. Among four heavy metals,the exceeding standard rate of lead was the highest（2.24%）,while the exceeding standard rate of cadmium was 0.67%,and the contents of inorganic arsenic and mercury did not exceed the standards. The year risk value of inorganic arsenic of rice in Taishan City was higher than level recommended by the USEPA（1 ×10^（-4）/a）. The year risk value of cadmium was higher than level recommended by the Swedish Environmental Protection Agency,the Royal Association of UK,and the Dutch Ministry of Construction and the Environment（1×10^（-6）/a）. The year risk value of lead was lower than the negligible risk level recommended by the Dutch Ministry of Construction and the Environment（1 ×10^（-7）/a）. The year risk value of mercury was lower than the negligible risk level recommended by the Royal Association of UK（1 ×10^（-8）/a）.[Conclusion]The heavy metals contamination of rice produced in Taishan City is still not serious.However,it is necessary to take scientific and feasible intervention measures according to the possible sources of heavy metal pollution,further reduce the pollution from arsenic and lead,cadmium,to minimize the potential human health hazards of heavy metals through ingestion pathway in rice.