CORRELATION ANALYSIS AND MODELLING OF HEAVY METAL CONCENTRATIONS AND PHYSICOCHEMICAL PARAMETERS FROM SOIL SAMPLES OF FIVE SELECTED REFUSE DUMPSITES IN LAFIA LOCAL GOVERNMENT AREA OF NASARAWA STATE, NIGERIA

Abstract

Thousands of tons of solid wastes are generated and disposed daily in open dumps of most Nigerian cities due to rapid population explosion and commercial activities. In this study, concentrations of heavy metals and physicochemical parameters from 20 soil samples each from selected refuse dumpsites in wet and dry seasons were determined using Atomic Absorption Spectrophotometer and Association of Official Analytical Chemists (AOAC) standard methods. The results showed that during the wet and dry seasons, the concentration of heavy metals, Hg, Cr, Mn were above that of World Health Organisation (WHO), and National Environmental Standards and Regulations Enforcement Agency (NESREA), while that of Pb, As, Fe, Zn, Cu and Ni were below the tolerable limits. The results for physicochemical parameters in wet and dry seasons for nitrates, phosphates and organic matter were above WHO standards. Statistical test at 0.05 probability level (p < 0.05) was used to determine the degree of association between pairs of the variables. The principal component analysis (PCA) was performed to measure the direct and inverse relationship between these parameters and heavy metal availability. Based on the different variables obtained at the study areas, a multiple linear regression analysis was determined from which a general linear model was formulated. The study recommends appropriate government agencies should as a matter urgency integrate the regular monitoring of waste disposal into the state developmental plan and framework in order to prevent excessive build-up of these metals in humans through the food chain.