Abstract

The concentrations of lead (Pb) and zinc (Zn) were quantitatively determined in surface and sub-surface soils in Enyigba, Ebonyi State, Nigerian’s major lead mining area using atomic absorption spectrophotometer. pH status of the soils was similarly determined. The survey was conducted to establish a base line pollution index for lead and zinc in Enyigba soil as an exogenous source of these metals among food crops. Agricultural soil samples were collected from the study area from each point about 2 km apart. Both surface and sub-surface soil were collected. The mean concentrations of lead (23.37 ± 0.16 mg/l) and zinc (2.02 ± 0.77 mg/l) in surface soil were significantly higher than the mean values of 3.64 ± 3.3 mg/l and 1.39 ± 0.30 mg/l respectively found in the sub-surface. The soil recorded a pH mean value of 7.0 ± 0.02. Trace element can affect the yield of crops and their composition; thus the determination of the elemental status of all cultivated soil has to be made in order to identify yield-limiting deficiencies of essential micronutrient and polluted soils. Lead is relatively unavailable to plants when the soil pH is above 6.5, while availability of zinc decreases with increasing soil pH due to increased adsorptive capacity.

Key words: Lead, zinc pH, surface and sub-surface soil.