First Results on the Effects of Direct Thermal Treatment on Soil Organic Matter and Availability of Heavy Metals

Abstract

To restore the soil quality a part of the most polluted soils in the Netherlands is cleaned, mainly by thermal treatment. This technique may result in a sufficiently decontaminated soil, but as a consequence of the technique important soil properties will also be drastically altered, thus soil structure and soil life will become e.g. completely absent. Moreover, thermally cleaned soils often contain residues of heavy metals. An integrated research program was set up to investigate the spontaneous ecological recovery of cleaned soils on existing field sites with predominantly thermally cleaned soils. An overview of results and references of this research program can be found in Tamiset al(1992b). The first results of this field research indicate an decreased availability of the heavy metals Cu, Zn and Cd (and not for Pb), such in contrast with expectations (see Tamiset al1992a). Since soil organic matter plays a major role in the availability of heavy metals, a preliminary research, reported in this article, have been carried out into the changes in soil organic matter and the changes in availability of Cu and Pb after thermal treatment.