Development of an analytical method for arsenic speciation in soils and contamination characteristics

Abstract

Arsenic contamination in soil has drawn attention because some arsenicals are very toxic, posing health risks through anthropogenic activities. This study described development of an advanced method for arsenic speciation (arsenite (AsIII), arsenate (AsV), arsenocholine (AsC), arsenobetaine (AsB), dimethylarsinic acid (DMA), and monomethyl arsonic acid (MMA)) in soil samples using high performance liquid chromatography/inductively coupled plasma-mass spectrometry (HPLC/ICP-MS). Two selected extraction strategies were compared: 1) A (4 mM NH4NO3 in 2% MeOH) and B (20 mM NH4H2PO4 and NH4NO3 in 2% MeOH, pH 8.5), 2) A (10 mM NH4H2PO4) and B (50 mM NH4H2PO4). The developed method was applied to determine arsenicals in real soil samples from As contaminated sites. Finally, high concentration of arsenicals indicated an anthropogenic pollution source from refinery and industrial sites.