Study On Geochemistry Behavior Of Pb Et Al Heavy Metals In The Dongting Lake Region Of Hunan Province

The heavy metal pollution of soil can threaten the safety of farm produce and the health of human. So it is the emphasis that study on geochemistry behavior of heavy metals in soil-plant system.In this paper, Pb regional eco-geochemical evaluation in the farmland ecosystem of the Dongting lake region in Hunan province is studied. We basically understand that ecological impacts and change trend of Pb in investigated area. Moreover, complex pollution and environmental capacity of soil are discussed.It is discussed that physics and chemistry character of soil effects on geochemical behavior of Pb. The results show that soil pH has significant impact on the bioactivity of Pb in soil of the Dongting region in Hunnan province. Furthermore, soil organic matter and clay act on adsorption, desorption and stabilization in solid of heavy metal. It is considered that magnetic susceptibility is an effective indicator for variation in heavy metal Pb concentrations.The results of ecological evaluation show that there are two reasons of the high concentration of Pb in the seed of rice.One is the high concentration of Pb in soil, the other is soil acidification and content of organic matter. Pb concentrations decreased rapidly from roots to grains along rice plants. People in investigated area eat rice with staple food, who absorb Pb concentrations less than ADI.In investigated area, Pb concentrations of vegetable are special higher than food health standards.Thereinto, capsicum> aubergine> beanstalk> corn> towel gourd> balsam pear> cucumber. By clustering analysis CF(Pb) of the crops, there were two groups among these seven crops. The first one included balsam pear and towel gourd; the second one included capsicum, bean, cucumber, corn and aubergine. The first group accumulated less Pb than the second one.The result of interaction showed that major element of nitrogen, phosphor, kalium and microelement of manganese, silicon , boron all have the influence on bioactivity of the element Pb.The result of compound pollution of Cd and Pb showed that the presence of Pb was helpful to the absorption of Cd, whereas the presence of Cd inhibits the absorption of Pb by rice.This paper adopted the NemerowSynthetical Pollution IndexMethod to assess the heavy metal pollution of soils. The results show that soils in Changsha, Xiangyin and Niluo are heavy metal pollution badly.Environmental capacity in investigated area is calculated. The conclusion shows that environmental waste of Pb, As and Hg are little, whereas environmental waste of Cd is great.