VERTICAL DIFFERENCE AND GEOCHEMICAL LAYER CHARACTERISTICS OF HEAVY METALS DISTRIBUTION IN THE SOIL OF GEOGRAPHICAL LANDSCAPES OF SOUTH GUANGDONG
广东南部地理景观中土壤重金属垂直分异及其地球化学分层性

The vertical difference of the distribution of heavy metals and their geo-chemical layer characteristics including Fe, Mn, Co, Ni, Zn and Pb in the soils of the Tropics and the Subtropics have been studied in this pape.The difference is reflected by the distribution in five forms including water-dis-soved, exchangeable, organic-bound, Fe-Mn oxide-bound and residual.There is a layered Characteristic of the form distribution of heavy metals in the soil.The concentrations of water-dissolved, exchangeable and organic-bound heavy metals descend from the upper layer to the lower layer in the soil profiles.The distribution of water-dissolved and organic-bound metals is consistent with the organic matter, and is contrary to the pH valve.The distribution of Fe-Mn oxide-bound metals is consistent with the clay particle. The distribution difference of the residual metal in every profile is very little.The order of potential mobility of heavy metals in the soila of geographical landscapes of the Tropics and the Subtropics is as follows.Fe>Mn>Pb>Cu>Zn>Co.