The Concentrations,Distribution And Pollution Assessment Of Cr,Cd,Pb And Ar In Latosols On The Hainan Island

The laterite that is typically developed extensively in Hainan Island was chosen as the object of study,the concentrations,distribution and pollution evaluation of Pb, Cr, Ar and Cd for soil samples were conducted, the results showed that:(1) The average concentration of four heavy metals is remarkable difference in latosols from different parent material growth on Hainan Island,in addition to Cadmium elements, the other elements are lower than natural background contents of soil background values of study areas in the coastal sand and Beach rock;They are generally higher natural background contents of soil background values of study areas in Sandshale laterite.(2) In the horizontal space,the mean value of four heavy metals content is difference,the distributed situation is in the order of low hill region > the table-coastal plain region > middle mountain region,in addition to Pb element;In the vertical space, the mean value of the soluble content of As element and Cr element increase gradually from the bottom to the top in Sandshale laterite and granite latosolic red soil's profiles,the average contents of Pb element and As element decrease gradually from the bottom to the top in Sandshale laterite and granite yellow-laterite's profiles.(3) The average concentration of the soluble four heavy metals is no significant difference in latosols from different parent material growth on Hainan Island,it is generally low in Shallow laterite,and is generally higher in Granite yellow-laterite and Granite latosolic red soil ; The average percentage of thesoluble elements and the corresponding average concentration has a positive correlation between the relationships in Shallow laterite and Sandshale laterite's profiles.(4) In the horizontal space,the mean value of the soluble content of four heavy metals is in the order of middle mountain region >low hill region > the table-coastal plain region,in addition to Pb;In the vertical space, the mean value of the soluble content of Cr increase gradually from the bottom to the top in Sandshale laterite,Arenaceous-pelite laterite and Shallow laterite's profiles,the average contents of As decrease gradually from the bottom to the top in Sandshale laterite,Arenaceous-pelite laterite and Granite latosolic red soil's profiles, the variation of other elements is not very regular.(5) According to the secondary standard of the Standard of Soil Environment Quality—(GB 15168—1995), Pb element has not pollution,while other three kind of elements (Cr, Ar and Cd) have slight pollution of different levels in the individual plot points,such as Wenchang and Danzhou;From the results of composite pollution index show the majority study area are cleaning , other areas has pollution,such as Danzhou (7.22, heavy pollution),Haikou (1.23, light pollution),Ledong (1.10, light pollution).(6) According to the soil environment quality standard of the study area, the single factor pollution index of Cr, As and Cd is lower;From the results of composite pollution index show that the cleaning areas occupies 36﹪, the light pollution areas occupies 42﹪, the pollution and the heavy pollution areas occupies 11﹪,Danzhou and Wenchang belong to heavy pollution areas.