Distribution and Mobility of Arsenic Species in Solidsand Leachate Composts

Because arsenic can exist in toxic and non-toxic forms, it is important to identify them in compost.This organic material prepared from urban and agricultural wastes, is often used for recovering orremedying soils. As a matter offact, it’s important to control the mobility of arsenic and itsdifferent forms present in leachate composts. In this work total arsenic was determined incompost samples,previously submittedto acid digestion using Inductively Coupled Plasma MassSpectroscopy (ICP–MS). Total inorganic arsenic and As(III) results were compared with thosedirectly determined in solids samples by Square Wave Voltammetry (SWV). It was found that twothirds of arsenic present in solids are in inorganic forms. As(III) is a minor component in the solid,detectable only in agricultural composts. In leachates, the inorganic arsenic wasmobilized in hismajority as As(III).