南宁市稻米重金属污染状况及环境因素分析

Analysis of heavy metal pollution in rice and environmental factors in Nanning

将2019年采于南宁市12个县区的稻米样本605份,检测并评价稻米中的重金属污染状况,分析其与土壤、水等环境因素危害的相关性。南宁市种植稻米重金属总超标率为23.30%,其中镉14.71%,无机砷5.62%,铅2.64%,总汞0.66%。镉的最高检出值为1.28 mg/kg。稻米中铅、镉、总汞、无机砷的综合污染指数(PN)为0.712,属于尚清洁水平。土壤和灌溉水中的重金属含量与稻米中重金属含量呈现低度线性相关,相关系数均小于0.4。南宁市种植稻米存在中度重金属污染,尤其是镉污染较为严重。在南宁区域内,环境因素造成的风险对稻米安全质量的总体影响比较小,尚在可控的风险范围内。由于稻米对环境尤其是土壤中重金属有富集作用,仍需持续关注。

605 rice samples were collected from 12 counties and districts of Nanning City in 2019.The heavy metal pollution in rice was detected and evaluated,and its correlation with environmental factors(soil and water)was analyzed.The total heavy metal exceeding rate of rice grown in Nanning was23.30%,among which cadmium was 14.71%,inorganic arsenic was 5.62%,lead was 2.64%,and total mercury was 0.66%.The highest detectable value of cadmium was 1.28 mg/kg.The comprehensive pollution index(PN)of lead,cadmium,total mercury,and inorganic arsenic in rice was 0.712,which was still clean.The content of heavy metals in the soil and irrigation water and the corresponding heavy metals in rice showed a low degree of linear correlation,and the correlation coefficients were all less than 0.4.There was moderate heavy metal pollution in rice planted in Nanning,especially cadmium pollution.The overall impact of risks caused by environmental factors on the safety and quality of rice was relatively small and within a controllable risk range in Nanning.It is still necessary to continue paying attention to the effect of rice on the environment,since rice can accumulate heavy metals,especially in soil.