Status evaluation of heavy metals in waste disposal sites of champion breweries and plasto crown company, Uyo, Akwa Ibom State, Nigeria

Abstract

Sludge and soil samples were collected through purposive sampling method within Champion Breweries and Plasto Crown Company waste disposal sites during wet and dry seasons for status evaluation of their heavy metals (Fe, Pb, Zn, Ni, Cr, Cd, Co and Hg) for comparison with the control site and the world threshold standards for tropical soils. The results showed that the sludge pH value of 7.89 during wet season signified alkaline medium (outside the natural range of acidic medium for soils in the Niger Delta region of Nigeria) which was attributed to the high calcium content of the brewery effluent. The 7.42 pH value during wet season for soil in the Plasto Crown Company waste disposal site indicated alkaline medium which was due to the remnants of the wastes which formed lime to neutralize the acidic medium of the soil while the electrical conductivity values (below 4 dSm-1) indicated the nonsalinity of the soils. More so, a two way analysis of variance (ANOVA) statistical method used to run the analysis revealed that the soil in terms of heavy metal concentrations did not exceed the world threshold standards.

Keywords: Soil, sludge, heavy metal concentrations, permissible standards.