汞矿周边稻田汞和甲基汞污染特征及生态风险

doi:10.19741/j.issn.1673-4831.2021.0512

摘要/Abstract

摘要： 为评估万山汞矿周边稻田汞污染特征及环境风险，协同采集了土壤和稻米样品并对其总汞(Hg)和甲基汞(MeHg)含量进行测定，分析其潜在生态风险和人体健康风险，并对比研究不同浸提剂对土壤有效Hg的提取效率。结果表明，调查区稻田土壤总Hg和MeHg含量范围分别为0.95~16.27 mg·kg^-1和2.06~3.99 μg·kg^-1，其中，总Hg含量超过农用地土壤污染风险筛选值，为中重度污染水平。土壤Hg以残渣态为主，占比为92.9%~94.6%，MeHg含量仅占总Hg的0.016%~0.285%。稻米总Hg含量达27.38~74.29 μg·kg^-1，超过国家规定的食品中污染物限量标准(20 μg·kg^-1)，但日人均摄入量指数(PDI)和目标危害系数(THQ)显示稻米Hg潜在健康风险较低；稻米MeHg含量为9.90~31.52 μg·kg^-1，部分采样点PDI超过美国环境保护局推荐的限量标准(0.1 μg·kg^-1·d^-1)，存在潜在暴露风险。Pearson相关分析表明，0.01 mol·L^-1 Na₂S₂O₃和0.1 mol·L^-1 HCl浸提态Hg与土壤和稻米总Hg、MeHg呈显著正相关(P < 0.01)，可较好表征稻田土壤Hg的有效性。

关键词: 汞, 甲基汞, 稻田, 风险评价, 有效性

Abstract: Collaborative samples of soil and rice were collected to assess the characteristics of mercury pollution and its environmental risk in paddy fields around Wanshan Mercury Mine. The potential ecological risks and human health risks of Hg were evaluated, and the extraction efficiency of available Hg in soils were compared among different extracting agents. Results show that the concentrations of total Hg and MeHg in paddy soils was 0.95-16.27 mg·kg^-1 and 2.06-3.99 μg·kg^-1, respectively. The Hg content in soils exceeded the risk screening values for soil contamination of agricultural land, being moderate and serious level of pollution. Most proportion of soil Hg were in the residue fraction (92.9%-94.6%), and the contents of MeHg only accounted for 0.016%-0.285% of total Hg. The amount of total Hg in rice grain was 27.38-74.29 μg·kg^-1, and exceeded the Chinese national standard limit of 20 μg·kg^-1, but the potential health risk of Hg was low according to the values of probable daily intake (PDI) and target hazard quotients (THQ). The contents of MeHg in rice grain were 27.38-74.29 μg·kg^-1, and the PDI of some sampling sites exceeded the USEPA recommended limit of 0.1 μg·kg^-1·d^-1, suggesting the potential exposure risk of MeHg. Pearson correlation results indicate that the available Hg extracted by 0.01 mol·L^-1 Na₂S₂O₃ and 0.1 mol·L^-1 HCl had significant positive correlations with total Hg and MeHg in soil and rice grain (P < 0.01), suggesting the two agents could be used to estimate Hg availability in paddy soils.

Key words: mercury, methylmercury, paddy field, risk assessment, availability

中图分类号:

裴鹏刚, 穆德苗, 马文艳, 孙涛, 孙约兵. 汞矿周边稻田汞和甲基汞污染特征及生态风险[J]. 生态与农村环境学报, 2022, 38(1): 112-119.

PEI Peng-gang, MU De-miao, MA Wen-yan, SUN Tao, SUN Yue-bing. Characteristic of Mercury and Methylmercury Pollution in Paddy Soils around Mercury Mine Area and Its Ecological Risk[J]. Journal of Ecology and Rural Environment, 2022, 38(1): 112-119.

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