Sequential extraction of nine trace elements from sludge-amended soils

Three separate samples taken from particular location of El-Gabal El-Asfar soils treated with composted sludge and irrigated with liquid sludge effluent were compared with untreated soil. These soils were sampled at 5 depths, i.e. 0–15, 15–30, 30–45, 45–60 and 60–75 cm to estimate the forms of nine trace metals in the solid phase. The soils had been amended with sewage sludge and irrigated with sludge liquids for different periods, i.e. 20, 40 and 60 years. The soil samples were fractionated by sequential extraction to estimate the quantities of these metals in “exchangeable”, “sorbed” “organic”, “carbonate”, and “sulfide” forms.