Arsenic speciation in municipal landfill leachate

Arsenic species in municipal landfill leachates (MLL) were investigated by HPLC–DRC–ICPMS and LC–ESI-MS/MS. Various arsenic species including arsenate (iAsV), arsenite (iAsIII), monomethylarsonic acid (MMAV), dimethylarsinic acid (DMAV), as well as sulfur-containing organoarsenic species were detected. Two sulfur-containing arsenic species in a MLL were positively identified as dimethyldithioarsinic acid (DMDTAV) and dimethylmonothioarsinic acid (DMMTAV) by comparing their molecular ions, fragment patterns and sulfur/arsenic ratios with in-house synthesised thiol-organoarsenic compounds. The findings demonstrated the potential for transformation of DMAV to DMDTAV and DMMTAV in a DMAV-spiked MLL in a landfill leachate environment.