Speciation of arsenic in coarse and fine urban aerosols using sequential extraction combined with liquid chromatography and atomic fluorescence detection

An analytical procedure for speciation of As in urban aerosol samples was d eveloped. The aerosols were collected by sequential filtration through memb rane filters. Part of each filter was investigated by INAA for the total am ount of As. Another part of the filters was treated by a sequential extract ion procedure to differentiate between water-extractable, phosphate-extract able and refractory chemical forms. Water-extractable forms were further di fferentiated into anionic As species by HPLC-HGAFS. Extractability of As in to water exhibited a clear dependency on the aerosol size fraction (12% in coarse fraction and 50% in fine fraction). Dependency of the phosphate extr actable As on the aerosol size fraction seems not to be significant (10-15% in both size fractions). The remaining amount, i.e., about 78% of the coar se As and about 40% of the Fine As was considered to be refractory or envir onmentally immobile As. Water-extractable As forms could only be attributed to arsenate.