keywords: Heavy metals, dumpsite, principal components, bi-plot sketch, score plot
Multivariate methods of data analysis were used to describe patterns of soil contamination with heavy metals in Lokoja city dumpsites. Groups of metals and dumpsites were identified using cluster analysis. Score plot was used to grouped dumpsites into four; Group I consists of Pata and Cinima dumpsites, while groups II, III and IV consist of Caturgo, High Court and New Market dumpsite respectively. The loading plot shows that Cu, Co, Cr and Cd have less significant contribution than the other five elements with positive value on the principal components. The bi-plot sketch shows the correlation between site samples and metals, in which Group I sample sites, consisting of sample 1 and 3, does not really correlates with particular metal, making it exceptional in terms of contamination. It is probably, the least contaminated among the sample site groups. Group II, consisting of sample site 4, is characterized by Zn and Cu. Group III, the group of sample site 5, has Co, Fe and Mn as main metal contaminant. Ni and Pb are dominant contaminants of Group IV. Strong and positive correlation co-efficient of element pairs are indicates common source. This can be observed in the cases of Fe and Mn, Zn and Mn, Zn and Fe, Co and Mn as well as Cd and Cr, whereas, Ni and Pb, originate from different pollution source. The cluster analysis gives pattern recognition based on the similarity and closeness of dump sites and the nature of the contaminants. The result reveals the closeness of sites 1, and 2 in terms of pollution level.