Sequential extraction of phosphorus and heavy metals from sediments: Methodological onsiderations

Two different sequential extraction procedures using hydroxylamine hydro-chloride or ammonium oxalate were tested for the analysis of P, Fe and heavy metals (Mn, Zn, Cuand Pb) in fine suspended and bottom sediments and in two sediment reference samples (NBS 1646: MESS-1). Both the procedures gave satisfactory results in terras of analytical reproducibility. However, element partitioning between some phases (reducible and oxidable) is dependent on the extractant used. The hydroxylamine hydrochloride sequence gave rsults that better fit with previous experimental data. The ammoniurn oxalate procedure should be preferred for P. A comparison with other "selective" techniques was performed.