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In developing countries, large amounts of waste are dumped daily in open dumping sites without proper management. This practice usually causes enhanced concentration of trace elements in environmental media within and beyond the vicinity of such dumps with attendant adverse environmental and health risks. The aim of this study is to assess and elucidate the major and trace element concentrations in soils around active and abandoned dumpsites in Lagos and also to do a comparative study with reference to possible environmental and health impacts. A total of 30 topsoil samples equally distributed around the two dumpsites (Ojota and Isolo) were collected. The soils were dried, disaggregated and sieved through a 2.00mm polyethylene sieve to appropriate fraction for analysis of trace elements using aqua-regia digestion technique and Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The following trace elements were found to have hazardous concentrations in soil and their levels of contamination based on contamination factor which was assessed by comparing the observed concentration of trace elements in soil with pre-industrial levels (crustal average) were 3.86 and 5.71 (As), 1.60 and 1.93 (Mo), 3.41 and 4.24 (Zn), 0.93 and 2.23 (Cu), 7.71 and 12.64 (Pb), 8.71 and 9.21(Cd) for both abandoned and active sites, respectively. Silver, Bi, Sb, Ga, Sc, Mn, Ga, La and Bi, Be, Sb, Co, Cu, La, Cr in soils showed higher values for samples close to the dumpsites (about 250m). The overall contamination degrees (the sum of contamination factors for all elements examined) for both abandoned and active dumpsites were 40and 30 for soil which indicate very high and considerabe degrees of contamination.
The samples around the abandoned dumpsite showed higher level of contamination than those of active dumpsite. These findings confirmed the fact that dumping waste indiscriminately is hazadous to human health and open dumps should be replaced with landfills that are environmentally friendly especially in Africa.
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