Electrokinetic soil remediation: an efficiency study in cadmium removal

296 The growth of industrial activity, along with the improper and uncontrolled disposal of waste generated by our society, is linked to the incidence of heavy metal (mainly Cr, Cu, Pb, and Ni) and/or organic pollutants (pesticides and other chlorine compounds) soil and groundwater contamination. Pollution of groundwater by non-biodegradable heavy metals is a matter of the greatest concern to public health. The governments of the industrialized countries spend substantial amounts of money trying to solve, or at least diminish, these pollution problems, the main difficulty laying both in its characterization (due to the complexity of the chemical composition of the soil), and the assessment of decontamination risks. The problem of decontamination of soils polluted with heavy metals is of great actuality in our country, particularly due to inactive or abandoned mining areas, like the ones found in Iberian Pyrite Belt in Alentejo (Portugal). They remain a risk mainly due to the unstable nature of the minerals exploited (essentially sulfides), that can cause very acidic waters and release potentially toxic metals such as lead, arsenic, mercury, cadmium, antimony, selenium, etc. In the past two decades, research has shown that the electrokinetic soil remediation is a viable, simple, and inexpensive technique that can be applied successfully to the removal of various heavy metals, in certain types of soils. Moreover, being a technology that encompasses natural physicochemical processes, it respects aspects such as sustainability and environmental ethics.