Characteristics Levels of Predictions of Extractable Metals (Cd, Pb and Fe) in Sewage

Sewage is the part of wastewater that is contaminated with feces or urine but is often used to mean any wastewater. When this is done sewage refers to wastewater from sources including homes, industries, medical facilities, street runoff and business. It consists of nutrients and organic matters that can provide soil benefits and are widely used as soil amendments. In an attempt to investigate the partitioning of three metals: Cd, Pb and Fe in sewage, standard operationally defined procedures; sequential extraction was employed in the study. The effect of extractant concentrations was also studied and found to affect extractability across the various fractions (reducible. oxidizable and residual). The highest acid extractable fraction (1.78 ±0.01mg/kg)was recorded in Fe while the least (0.16±0.01mg/kg)was found in cadmium. The reducible fractions across the various concentration ranged from 0.03-0.23 mg/kg for Cd,0.01-0.43 mg/kg for Pb and 1.04-2.54 mg/kg for Fe. For the oxidizable fraction, the range was 0.15-0.24 mg/kg in Cd,0.006-0.23mg/kg in Pb and 0.556-2.08 mg/kg in Fe. The residual fraction across the three experimental design of variable pH and 0.79-1.07-0.21mg/kg for Cd,0.01-0.8 mg/ kg for Pb and 0.79-1.07mg/kg for Fe. The findings showed that the metal ions binding to the biotic surface such as sewage is pH dependent and that is an optimum pH for bioavailability of metals, also the pH changes during extraction was dependent on the composition of the sample. The sewage pH and organic matters influence was observed only on cadmium (r= -0.970 at p