ADSORPTION OF TRACE-METALS BY TENSION LYSIMETERS - NYLON MEMBRANE VS.POROUS CERAMIC CUP

Lysimeters constructed of polyacrylic and fitted with either a porous nylon membrane or a porous ceramic cup were tested for their adsorptio n characteristics with respect to Ph, Cr, Cu, As, Cd, Co, Mn, Ni, and Zn. Laboratory tests were conducted at pH 4, 5, and 6 using metal conc entrations that are representative of natural soil solutions. The cera mic lysimeters significantly lowered the concentrations of Cd, Co, Mn, Ni, and Zn, and almost completely removed Ph, Cr, Cu, and As from sol ution. The nylon lysimeters had virtually no effect on metal concentra tions at pH 4 to 5, and only slightly decreased the concentrations of As, Cr, Cu, and Ph at pH 6. Based on field experience, an optimized de sign of the nylon lysimeter is presented using double nylon membranes to improve the mechanical resistance.