EXTRACTABILITY OF ADDED LEAD IN SOILS USING LEAD-210

Four soils of different physical and chemical characteristics were treated with 10 ppm lead in the form of PbCl2 labelled with lead-210 (2.5 mCi/g 207Pb) and subjected to a 7-wk incubation period. The extractability of the added lead was assessed using 12 extractants. Almost complete recovery (93–98%) of the applied lead was obtained with 6 N HNO3. Large amounts of the applied lead [Formula: see text] could be extracted by chelating agents (DTPA and EDTA). Relatively small amounts were exchangeable with 0.5 M BaCl2 (0.1–4%) and N NH4OAc (1–11%). Proportionally slightly higher amounts were extracted with 2.5% AcOH and 0.5 M NaHCO3. Only traces could be found in the 0.05 M CaCl2 extract.