A GEOLOGICAL INTERPRETATION OF HEAVY-METAL CONCENTRATIONS IN SOILS AND SEDIMENTS IN THE SOUTHERN NETHERLANDS

The natural variation in heavy metal contents of subsurface sediments in the southern Netherlands is described, based on a series of 820 bul k geochemical analyses. The detrital heavy metal contents of these sed iments show linear correlations with Al as a result of their joint occ urrence in phyllosilicates. Anomalous enrichments occur as a result of the presence of glauconite (As, Cr, Ni, Pb, Zn), pyrite (As) or Fe-ox ides (As, Ba, Ni, Zn), due to the interaction of organic-rich subsurfa ce material with groundwater (Go, Ni, Zn) or as a result of anthropoge nic pollution in topsoils (Cu, Pb, Zn). The contents of Al, Fe, K and S are well suited to determine background values, and to identify the cause for anomalous accumulations of heavy metals. (C) 1997 Elsevier S cience B.V.