Migration And Transformation Of Mercury In Soil-Crop System And Risk Assessment

Migration and transformation of mercury and risk assessment were studied through field investigation and pot experiment in this paper.The main contents can be summed up as follows:1.The content distribution characteristics of mercury and methyl mercury in soil and crops,migration and transformation of mercury.2.Migration and transformation of mercury in soil-potato systerm and soil-wheat system.3.Risk assessment of mercury in crop.The main results can be summed up as follows:1.There were mercury and methyl mercury pollution in the soil and corn on both side of the Baiyin outfall.The range of THg contents were 0.0608?4.8705 mg/kg in soil,the average content of THg was 0.7268 mg/kg,and 35%of the samples were polluted,mercury posed slight pollution in the soil.The range of MHg contents were not detected?0.7323 ?g/kg,the average content of MHg was 0.1230 mg/kg,MHg in the soil could pose slight pollution.the average of mercury methylation rate was 0.03%,the methylation process of mercury was slow.The range of THg contents were 0.0111?0.0602 mg/kg in corn,and 55%of the samples were polluted,the average content of THg in corn was 0.0258 mg/kg,enrichment coefficient was 5.8%,Hg could pose slight pollution in corn.The range of MHg contents in corn were not detected?0.924 ?g/kg,the average content of MHg in corn was 0.138 mg/kg,the mecury methylation rate in corn was 0.8%,the enrichment ability of methyl mercury was very strong.There was no risk of THg and MHg on human body health.2.The range of THg contents were 0.217-0.285 mg/kg in the soil of potato potting,MHg was not detected in both soil and potato,Sludge composting made the content of methyl mercury decreased by 91%.Sludge could improve soil situation.there was no obvious effect on THg,MHg when sludge was added into soil.With the adding amount of sludge increased,the potato's enrichment ability of mercury was enhanced,Sludge had no risk of THg?MHg on human body health.3.Mercury influenced EC and organic matter when it was added into soil.With the adding of mercury increase,seed germination rate of wheat increase at first and then decrease,the length of wheat decreased,wheat biomass decreased,mercury enrichment and migration ability of wheat decreased.The enrichment ability of mercury in jointing stage of wheat in ranking were root>leaf>stem.The migration ability of mercury in Jointing stage of wheat in ranking were leaf>stem.After the wheat mature,enrichment ability of mercury in ranking were root>chaff>stem leaf>grain,The migration ability of mercury in ranking were leaf>chaff>grain.MHg was not detected in both soil and wheat.Mercury adding more than 5 mg/kg to soil was harmful to human health.