云南省不同产地大米重金属砷污染风险分析

摘要

Objective To analyze the potential arsenic contamination hazard in rice growing regions across Yunnan province. Methods The inorganic arsenic content of 2592 rice grains in 118 counties (cities/districts) of 16 prefectures (cities/districts) of Yunnan province were analyzed by LC-AFS6500 atomic fluorescence photometer, and correlation analysis, variance analysis and LSD multiple comparisons were conducted. Results The average value of inorganic arsenic in the samples was 0.028 mg/kg. Among them, the order of inorganic arsenic content was:industrial and mining enterprises surrounding farmland (0.036 mg/kg) >general farmland (0.026 mg/kg)>sewage irrigation farmland (0.021 mg/kg), the risk of heavy metal arsenic pollution in the surrounding farmland of industrial and mining enterprises was the greatest, and differences were significant with F value of 16.994. The content of inorganic arsenic in farmland and wastewater irrigated farmland in industrial and mining enterprises was the highest in Honghe state, which was 0.128 and 0.055 mg/kg, respectively, whereas from normal field, Lijiang city had the highest arsenic concentration, which was 0.078 mg/kg, and differences were significant from other cities. Puer city has the lowest average arsenic concentration and detection rate among 16 districts. Among 2592 samples, 13 of them were over legal limit, account for 0.50% of the sample, and they were all from Honghe district, of those 6 samples were from Gejiu city, 5 samples were from Mengzi city and 2 samples were from Kaiyuan city. Conclusion The agriculture micro-environment of the field is an important factor of arsenic contamination in the rice growing regions and fields adjacent to factory have much higher potential of arsenic contamination which should draw our special attention.%目的 分析云南省不同产地大米重金属砷的污染风险.方法 采用LC-AFS6500型原子荧光光度计,分析采集自云南省16个州(市)水稻主要产区的118个县(市/区)2592份稻谷的无机砷含量,并进行相关性分析、方差分析和LSD多重比较.结果 供试样品无机砷含量的平均值为0.028 mg/kg,其中,工矿企业周边农田(0.036 mg/kg)>一般农田(0.026 mg/kg)>污水灌溉农田(0.021 mg/kg),以工矿企业周边农田重金属砷污染风险最大,经方差分析,F值为16.994,呈极显著差异.工矿企业周边农田和污水灌溉农田无机砷含量均以红河州为最高,分别为0.128、0.055 mg/kg,一般农田则以丽江市为最高,为0.078 mg/kg,且均与其他所有州(市)均呈极显著差异;普洱市的无机砷均值在16个州(市)中为最小,检出率最低;2592个样品中,有13份样品无机砷含量超限,占供试样品的0.50%,均采自红河州,其中个旧市6份、蒙自市5份和开远市2份.结论 农业生态环境是影响大米重金属砷污染的重要因素,建议应对工矿企业周边农田重金属砷污染给予重点关注.