ANALYZING SOIL COMPOSITION AND METAL CONTAMINANTS IN WASTE DISPOSAL SITES IN NSUKKA

Disposal of waste on the soil surface affects both the physico-chemical properties and the concentrations of heavy metals in the soil. Following a field reconnaissance at the University of Nigeria, Nsukka Southeastern Nigeria, two representative dumpsites and adjacent control sites at Odim-gate and Faculty of Engineering (FOE) were selected to assess some soil physico-chemical properties, including heavy metals concentrations, at 0-20 and 20-40 cm depths. The soil data obtained from the sites were arranged in a 2 x 2 x 2 factorial and analyzed. Results showed that the soils were generally sandy loam, slightly acidic to slightly alkaline, with a high available P content, while the concentrations of organic carbon (OC), total N, Ca2+, Na+ and K+, including effective cation exchange capacity, were low. Saturated hydraulic conductivity and OC content were significantly higher at the Odim-gate, while soil pH, available P, Al3+ and H+ concentrations were significantly lower than at the FOE location. Soil bulk density, and concentrations of Al3+ and H+ were significantly lower, while total porosity, pH, OC, Ca2+ and Na+ concentrations increased in the dumpsite compared to the control. The OC, Ca2+, Na+ and K+ were significantly higher in the topsoil (0-20 cm), while Al3+ was significantly lower. Heavy metals Fe and Pb concentrations in the soils were low, although the Fe concentration at the Odim-gate location and the control site was significantly higher than their corresponding counterparts. The high Zn concentration at both locations, particularly at 0-20 cm depth at the FOE dumpsite, poses a potential risk to the environment and human health as Zn accumulates to toxic levels