ABSTRACT
This chapter discusses and evaluates in situ gentle remediation measures, discusses the complementary relationship between stabilization and decontamination, and evaluates the possibilities of decontamination with techniques other than the use of plants. The decision to remediate a site or not is made on the basis of the degree of the risk posed by a further spread of heavy metals. For polluted sites which pose a severe risk of further spread of the contaminants, only harsh methods are suitable, but for larger areas and soils with diffuse sources of pollution below a certain degree of contamination, gentle remediation techniques are ecologically and economically reasonable alternatives. Gentle remediation methods may be used in soils with heavy metal concentrations between the trigger value and the cleanup value. Most experiments investigating the effect of liming on the availability of heavy metals were made in soils that had received high doses of sewage sludge.
