In recent years, there has been increasing interest in employing electro-bioremediation, a hybrid technology of bioremediation and electrokinetics for the treatment of soil contaminated with hydrophobic organic compounds (HOC). Present electro-bioremediation approaches however mainly aim at pollutant extraction through transport over large distances and tend to neglect both the impact of direct current (DC) on organism-soil interactions and microscale HOC release rates. Accordingly, no data are available on bioavailability changes acting via DC-driven effects on organism-compound and organism-soil interactions. This is a serious gap of our current knowledge hampering the improvement of the electro-bioremediation methodology. This review establishes a conceptual framework of the various influences of DC on processes governing HOC-bioavailability in soil. in particular the DC influence on microbial physiology and the physico-chemistry of organism-soil and organism-compound interactions. (c) 2006 Elsevier Ltd. All rights reserved.