Influence of redox potential on arsenic release from soil in the presence of iron oxyhydroxide

This paper presents the effects redox potential on the mobility of arsenic (As) from soil in the presence of iron oxyhydroxide with soil column experiment. The mineralogical characteristics of the soil were identified by acid digestion, X-ray diffraction and sequential extraction methods. Approximately 60% of the total arsenic was associated with iron oxyhydroxides and iron oxides. Redox potential played a significant role on the onset of arsenic and iron release from the soil. The arsenic and iron concentration of the effluent from the soil column suggested that the release of arsenic was related to reductive dissolution of Fe-oxyhydroxides. Results of soil column experiment also imply that arsenic remains being adsorbed to iron oxyhydroxide until its surface area becomes small because of transformation into more stabilized form.