2014—2018年南宁市大米重金属含量监测及膳食风险评估

Heavy metal content monitoring and dietary risk assessment of rice in Nanning City from 2014-2018

目的了解南宁市大米中主要的重金属含量,评估其对人体的健康危害。方法2014—2018年在南宁市15个所辖县(区)采集1528份市售及农户自产大米,检测铅、镉、无机砷、锌和硒元素的含量。结果铅、镉、无机砷检出率分别为51.35%、94.38%、84.69%,总超标率为23.8%。各县(区)均有超标现象,来源于县产的大米铅、镉、无机砷超标率均高于城区。产自本地的大米镉超标率明显高于外地(P<0.01)。来源于农户自产的大米镉超标率高于农贸市场和超市;Cd/Zn=0.0065,低于健康临界值;硒的平均含量为(0.042±0.395)mg/kg,中位数为0.033 mg/kg;铅、镉、无机砷每日摄入量(EDI)分别为0.169×10^-3、0.525×10^-3、0.513×10^-3mg/kg,低于美国环保署水资源处(USEPA)规定的限量标准;高危商值(HQ)分别为0.030、0.370和0.018,高危指数(HI)为0.418,HI<1。对武鸣县、上林县和江南区3个镉超标率居前3位的县(区)进行评估,武鸣县大米HI>1。结论南宁市大米普遍存在重金属污染,尤其产自本地的大米镉污染较为严重,食用武鸣县产的大米对人体健康存在慢性毒性。需引起足够重视和采取治理措施,确保食品安全。

Objective To understand the main heavy metal element contents of rice in Nanning City,evaluate the harm to human body.Methods Totally 1528 samples of rice sold in the market or produced by farmers were collected from 15 counties(districts)in Nanning City from 2014-2018,to detect the contents of lead,cadmium,inorganic arsenic,zinc and selenium.Results The detection rate of lead,cadmium,inorganic arsenic was 51.35%,94.38%and 84.69%respectively,and the total over standard rate was 23.8%.The over standard was found in every counties(districts).The over standard rates of lead,cadmium,inorganic arsenic in the rice produced in counties were higher than those in rice produced in urban area.The over standard rate of cadmium in local rice was higher than that in rice produced in other place(P<0.01).The Cadmium from farmer produced rice which was higher than the market and supermarket sold.The over standard rate of cadmium in rice from farmers was higher than that in rice from farmers’markets and supermarkets.Cd/Zn=0.0065,it was lower than the critical value health.The average content of selenium was(0.042±0.395)mg/kg,with the median of 0.033 mg/kg.The daily intake(EDI)of lead,cadmium,inorganic arsenic was 0.169×10^-3,0.525×10^-3 and 0.513×10^-3 mg/kg,respectively,which were lower than the limit stipulated by the Water Resources Branch of USEPA.The HQ(non-cancer risk quotient)was 0.030,0.370 and 0.018,respectively.The HI(High Risk Index)was 0.418,HI<1.Wuming County,Shanglin county and Jiangnan District,where were the top three areas with the over standard rate of cadmium,were evaluated,and HI in Wuming County was higher than 1.Conclusion Heavy metal pollution is common in rice in Nanning City,especially cadmium pollution in local rice.Eating the rice produced by Wuming County has chronic toxicity to human body health.It is necessary to pay an enough attention and take control measures to ensure food safety.