STUDIES OF SOIL POLLUTION IN NSUKKA URBAN, SOUTHEASTERN, NIGERIA

Abstract

Several studies have shown that soils within urban areas can be severely contaminated by heavy metals. In present study, 11 surface soil samples were collected from dumpsites, mechanic village, agricultural farmland, sewage lodge, major market, motor park and major abattoirs throughout the Nsukka urban for analysis. The concentration levels of Fe, Mn, As, Pb, Zn, Cd, Cr, Ni, Cu, and Hg in these samples were measured and statistically analysed using standard procedures. The spatial distribution of heavy metals was analysed by the inverse distance weighted (IDW) interpolation method. Pearson correlation matrix was used to ascertain contamination sources of ten heavy metals and to determine the contribution of each source. Results of the analysis show that the concentrations of heavy metals in many samples exceeded the values defined by the World Health Organization/Food Agricultural Organization (WHO/FAO). However, the concentration of all heavy metals were also higher than their control sample values. The sequence of heavy metals in the soils of Nsukka urban was in following order Fe > Zn > Cr > Cu > Cr > Pb > As > Ni > Mn > Cd > Hg. The results show that contribution from land use in Nsukka urban are in the order of dumpsite > abattoirs > sewage lodge > mechanic village > agricultural farmland > motor park > market. This clearly demonstrates that anthropogenic activities have markedly higher contribution rates to heavy metal pollution in soils of Nsukka urban than geogenic sources.