CONTENT, STATE AND CORRELATION OF SOME OF THE HEAVY METALS IN SOILS OF EAST SUBURB OF BEIJING AND ITS SIGNIFICANCE IN ENVIRONMENTAL QUALITY ASSESSMENT
北京东郊土壤中某些重金属的含量、形态、相互关系及其在环境质量评价中的意义

An investigation on content, state of some of the heavy metals, its relationship between them in soil, and its significance in environmental quality assessment was conducted.In field conditions, the major residual form is that of cadmium under treatment. The order of percent of six metals extracted with NH4OAC is Cd(12.97)>Cu(1.32)>Ni(1.06)>Zn(0.61)>Pb(0.24)>Cr(0.09), while that of six metals extracted with DTPA is Cd(33.10)>Cu(20.52)>Zn(4.25) >Ni (1.19)>Pb(0.92)>Cr(0.16).The existing form of cadmium in soil depends on the cadmium compound applied to soil. A considerable amount of cadmium was found in more soluble form in soil in east suburb of Beijing.An important correlation exists among contents of heavy metals, those with NH4OAC and DTPA extracted and total content in soil.A comprehensive assessment on concentration of six heavy metals was made by calculating with the correlation equation. The calculated assessment values agree well with the practical assessment values.