Abstract
In a Lysimeter experiment, the impact of CI- and SOt anions on. the movement/retention of lead and chromium in a sandy loam soil was studied. The treatments were: canal water application alone, solutions of PbCI2 ,'CrCI3 , Cr2(S04)3'PbCl2+ CrCl3 and PbCl2 + Cr2(S04)3in canal water containing 10 mg of each metal. These leaching solutions were applied in four splits, each equal to one pore volume (PV), while the fifth PV was the canal water. Lysimeters were protected from evaporation and rainfall by' putting a plastic sheet at about 30 cm height above the top of lysimeters. After infiltration of each P~ leachates were collected, measured and analysed for these metals by using atomic absorption spectrophotometer. After termination of the experiment, soil samples from lysimeters were drawn and processed for determination of Pb and Cr by using the. same atomic absorption spectrophotometer. It was observed that soil retained more Cr3+from added as CrCl3 than that as Cr2(S04)3 solution. However, there was no consistent effect of anions on leaching of Pb through soil. Ammonium bicarbonate-DTPA extractable Pb in soil was more for the added Cl' salts than that for the Sot salt solutions. Since the soil originally contained high concentration of Pb and Cr, the canal water because of its high water potential affected considerable leaching of these metals. Overall, a fraction of the applied Pb (1.59 - 4.56 %) and Cr (3.82 - 13.78 %) was removed in leachates while the rest was retained by soil. Key words: lead, chromium, leachate, sandy loam, pore volume, retention, water potential, chloride, sulphate
