The filtered solution was made up to 100 ml with distilled±deionized water. Samples were analyzed for Cu, Pb, Zn and Cr by a flame atomic absorption spectrophotometer (Perkin-Elmer Model 3030) using air± acetylene flame with deuterium lamp background correction.
Cd and Al were analyzed by an atomic absorption spectrophotometer Perkin-Elmer Model 3030 equipped with a graphite furnace (Perkin-Elmer Model HGA-600 Graphite Furnace and AS-60 autosampler)