FRACTIONAL DISTRIBUSTION OF SOIL CONTAMINATED WITH LEAD NITRATE AND CADMIUM NITRATE USING SEQUENTIAL EXTRACTION METHOD

A separate pot experiment was conducted to compare the metal uptake of soil spiked with amount of lead nitrate (Pb0- 0 mg/kg, Pb1- 1000 mg/kg, Pb2- 500 mg/kg, Pb3- 250 mg/kg, Pb4- 125 mg/kg, Pb5- 62.5 mg/kg), cadmium nitrate (Cd0- 0 mg/kg, Cd1- 1000 mg/kg, Cd2- 500 mg/kg, Cd3- 250 mg/kg, Cd4- 12 5mg/kg, Cd5-62.5 mg/kg) and the combination of the two salts using maize plant. The experiment was carried out under a greenhouse condition for ten weeks; the maize cob was harvested and analysed with Atomic Absorption Spectroscopic (AAS). Sequential extraction was used to fractionate the spiked soils into five operationally defined groups: Exchangeable, Carbonate, Fe-Mn oxide, Organic and residual. The Organic fraction was the most abundant pool for the soil spiked with lead nitrate while Carbonate is the most abundant for that spiked with cadmium nitrate and the results obtained from the combination of the two salts indicated that Organic fraction was the most abundant. Metal distribution in the different chemical fractions in these soils depends on the respective total metal concentration used to spiked the soil.