沼灌条件下水稻植株中汞及甲基汞的含量及食用风险研究

Concentration and Edible Risk of Total Mercury and Methylmercury in Rice Paddy Irrigated with Biogas Slurry

为了解沼灌条件下水稻植株中汞及甲基汞的含量及分布特征,并评估沼灌带来的人群暴露汞及甲基汞风险,运用野外现场样品采集与实验室分析相结合的方法,对沼灌条件下水稻植株各部位汞及甲基汞的含量进行了分析和测定。结果表明,沼灌区水稻籽粒中甲基汞的含量范围为0.38~3.51μg/kg,平均值为1.63μg/kg,中值为1.12μg/kg。沼灌区稻田土壤中甲基汞的含量与对应的水稻籽粒中的甲基汞的含量之间呈显著正相关关系(r=0.580*,P=0.048,n=12)。水稻籽粒中甲基汞的含量与总汞的含量呈极显著的正相关关系(r=0.824**,P=0.001,n=12)。水稻植株各部位汞的含量表现为根>叶>茎>籽粒。水稻植株各部位甲基汞的含量表现为籽粒>根>茎>叶,沼灌区稻米中总汞和甲基汞对当地居民健康风险贡献分别为5.06%~10.90%和1.93%~17.83%,说明沼灌区居民存在通过食用稻米而摄入汞及甲基汞的风险,但风险较低。

To measure the content of mercury(Hg)and methylmercury(MeHg)in rice from paddy with biogas slurry irrigation(BSI)and evaluate the risk of Hg and MeHg exposure through rice consumption for local residents,the soil and plant samples from the BSI paddy were collected and analyzed.The results showed that the content of MeHg in the rice grain ranged from 0.38 to 3.51μg/kg with an average of 1.63μg/kg and median value of 1.12μg/kg.There was a significant positive correlation between the contents of MeHg in paddy soil and in rice grains(r=0.580*,P=0.048,n=12).The content of MeHg in rice grain was significantly positively correlated with total Hg content(r=0.824**,P=0.001,n=12).The order of Hg content in different parts of the BSI rice plant was:root>leaf>stem>grain,MeHg content was:grain>root>stem>leaf.The contribution with total Hg mercury and MeHg in the BSI rice health risks of local residents were 5.06%~10.90%and 1.93%~17.83%,indi?cating Hg and MeHg exposure risk by consuming rice from the BSI paddy,but the risk was lower.