Four western New York soils differing in soil type and land use were subjected to (i) extraction of As by 14 solutions for soil‐solvent mixtures shaken for 1, 3, 7, and 18 hours; (ii) a sequential extraction with solvents designed to identify water soluble‐As (Ws‐As) and As associated with Al (Al‐As), Fe (Fe‐As), and Ca (Ca‐As); and (iii) a hot HNO 3 ‐H 2 SO 4 digestion to determine “total” As. Arsenic was determined by atomic absorption spectrophotometry employing arsine generation. In each soil sample the sequential extraction demonstrated that Fe‐As >> Ca‐As > Al‐As > Ws‐As; the total amount removed by the sequential extraction was only 34 to 41% of the total As in three low As (15.0 to 16.4 µg/g As) soil samples and 98% in a lead arsenate‐sprayed orchard sample containing 52.1 µg/g As. Deionized distilled water, 1 N NH 4 Cl, and 0.5 M solutions of CH 3 COONH 4 (“NH 4 Ac”), NH 4 NO 3 , and (NH 4 ) 2 CO 3 generally removed < 0.1 µg/g As from the soils. For the more effective solvents, the amount of As extracted increased with shaking time but an 18‐hour shake never exceeded 80% of that extracted sequentially for any sample. The relative effectiveness of the basic solutions in removing As was in the order of 0.5 M NH 4 F ≈ 0.5 M NaHCO 3 < 0.5 M (NH 4 ) 2 CO 3 < 0.5 M Na 2 CO 3 < 0.1 M NaOH; for acid solutions the order was 0.05 N HCl + 0.025 N H 2 SO 4 ≈ 0.5 M HCl < 0.5 M KH 2 PO 4 < 0.5 N H 2 SO 4 . Arsenic extraction data obtained in this study are consistent with the view that P and As react similarly in solutions containing acetate, sulfate, fluoride, bicarbonate, hydroxide, and hydrogen ions.
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Johnston et al. (1979) studied this question.