Selective extraction and determination of metals in organic stream sediments

Abstract

The effects of pre-treatment (drying, homogenizing and ashing temperature) on metal leachability and the effectiveness of extractants for metals and arsenic are described. Nine organic stream sediment samples were collected from non-polluted and two from polluted catchment areas. Buffered 1 mol dm–3 ammonium acetate at pH 4.5, buffered 1 mol dm–3 ammonium acetate with a chelating 0.02 mol dm–3 ethylenediaminetetraacetic acid agent at pH 5.5 and 3.5, and 0.2 mol dm–3 ammonium oxalate with 0.2 mol dm–3 oxalic acid at pH 3.0, were used separately to extract mobile and hydromorphic Al, As, Cd, Co, Cu, Cr, Fe, Pb, Mn, Ni and Zn for determination. Hot 6 mol dm–3 hydrochloric acid, hot 7.25 mol dm–3 nitric acid and hot aqua regia[HCl—HNO3(3 + 1)] leaches were used in the determination of the total element content.