LAUSR

An in situ method for spreading iron amendments to arsenic (As)-contaminated soil has been investigated in the laboratory and field. This study tested the distribution of Fe from corroding electrodes through soil using a low-voltage direct current in a laboratory setting and validated the method in the field for As immobilisation in contaminated soil. Laboratory tests revealed that the corrosion of Fe electrodes in soil occurred in a way similar to that during the Fe electrocoagulation in water, which decreased the As concentrations in flow-through water from 150 μg L-1 to undetectable levels. Method validation over one year in the field using electric current pulses with reversing polarity revealed a decrease in As concentration in groundwater by 72-97% in five of the six groundwater wells within the experimental area. This method of introducing Fe amendments to soil can reduce the need for soil excavation upon chemical immobilisation of contaminants in soil.