2004 Volume 55 Issue 1-2 Pages 1-18
In order to characterize the geochemical map of soil elements, major and minor elements were determined for Kuroboku soils, brown forest soils and alluvial soils collected in the southern Kanto district, Japan. The effects of biological accumulation on the soil elements are evaluated with the analyses of several plant materials. Compared to the crustal abundance, the plant materials are often enriched in P, Sb, Zn, Cd, Cu, Ca, Pb, Bi, Mn, Sr, K, Mo, As and Sn, but depleted in Al, Ti, Fe,Li, Cs, Tl, Be, Co, Cr, Ni, V, Ga, La, Ce, Th, U, Y and Zr. Most of the elements enriched in plant materials are generally dominant in the uppermost soil layers, reflecting the biological accumulation process. Whereas the elements depleted in the plant materials are clearly lower in the upper soil layers than the deeper one. This may be caused by the diagenetic transportation and the diluting effects by soil water and organic materials which accumulated during soil forming process. It is assumed that the parent material of the studied Kuroboku soils originated from the atomospheric transport materials such as altered tephra, reworked crustal materials with the fine particles of aeolian dust. The brown forest soils are composed mainly of altered basement rocks, and a small amount of the atomospheric transport materials. Both clastic materials derived from basement rocks and the atomospheric transport materials are significant sources of the alluvial soils. Compared to the noncultivated soils, cultivated soils are dominant in K and P through its suppying the manures. There is a clear difference in the chemical composition of the river sediments and the soils. In some samples collected around the highly industrialized areas, recent anthropogenic pollution for heavy metals are recognized. The geochemical mapping according to analyses of the soil itself will be useful for evaluation of recent environmental pollution and estimation of background level concentration of soil elements.
