Electrochemically induced reactions in soils-a new approach to the in-situ remediation of contaminated soils?: Part 2:: remediation experiments with a natural soil containing highly chlorinated hydrocarbons

An observed decay of immobile organic substances is not explained by the theory of electrokinetic soil remediation, when they are not transported by means of the electric field (electro-osmosis or -phoresis), as it is the case for chlorinated hydrocarbons like hexachlorobutadiene. It is assumed that the decrease of those substances is based on the presence of 'microconductors', particles with electronic conducting properties (e.g. metal oxides or others), inside the soil matrix. They are supposed to be able to induce electrochemical reactions in the vicinity of the contamination. Another possibility for the observed decay in their concentration are elimination reactions. Experiments and results with a natural soil containing chlorinated hydrocarbons with high boiling points coming from an industrial contamination site are presented. A decay of 80% and more for some of the substances could be observed. Degradation products (DP) with less chlorine in the molecule structure have been detected. Thus, redox- and elimination-reactions are possible. High pH-values seem to enhance the remediation. (C) 2002 Elsevier Science Ltd. All rights reserved.