Extraction of Cobalt and Cadmium in Municipal Dump Sites around Zaria, Kaduna State Using EDTA and Citrate as Complexing Agents

Abstract

Heavy metals contamination of the soil is detrimental to the environment with implications for human health. This result from several anthropological activities, urbanization and industrialization. Cobalt and cadmium are among the heavy metals of interest in Nigeria.The labile fractions of cobalt and cadmium in the soil from two dumpsites using EDTA and Citrate as complexing agents was evaluated. The Physiochemical parameters and the total metal concentrations of the soil was determined, extraction with EDTA and Citrate were used to study the potential metal extraction capacity at different time intervals and the extraction rates of metal was released as a function of time . The relatively low levels of silt, clay, organic matter and CEC indicates high permeability, hence leachability of heavy metals in the soil and suggest that it might be amenable to remediation by soil washing. Thus result shows that EDTA yielded much more than citrate for both metals under consideration. Therefore extraction time plays a very important role in soil washing process and determines the optimum contact time for contaminants removal. Hence the removal of metals from the soil is a function of time and concentration. Cadmium was extracted more than cobalt, which suggests cadmium has been more labile in solution than cobalt and EDTA as a stronger complexing agent than citrate.