Impact of Leachate on Physcicochemical Properties of Soil, Within the Vicinity of Oghara Medical Dumpsite, Delta State Nigeria

Assessing the level of toxic metals in pollution prone areas is imperative in order to ascertain their present levels. Top soil TS (0-15 cm) and sub soil SS (15-30 cm) samples and leachate were obtained in Oghara Teaching Hospital dumpsite. Three locations in the dumpsite were sampled. The soil and leachate was characterized using standard methods. The results shows that the pH was acidic with a range value of 4.26-5.48, electrical conductivity EC (29-197 /cm, cation exchange capacity CEC (11.58-25.10) meq/100g, nitrogen N (0.21-0.49) %, organic matter O.M (3.77-9.18) %, organic carbon O.C (2.18-5.31) %, SO42- (5.66-29.53) meg/100 g, PO43- (5.07-54.29) meg/100 g, Clay (13.60-17.62) %, Silt (2.21-2.99) % and Sand (79.86-84.13) %. The soil samples contain elevated levels of heavy metals with iron having the highest concentration. The metal concentrations are; 3328.50-6569.40, 117.70-267.70, 49.38-205.76, 11.63-87.21, 1.50-5.45 and 10.29-18.57 mg/kg for Fe, Zn, Mn, Cu, Cd and Pb respectively. The fractionation results follows the order B1 > R > B2 > B3. The mobility factor was high which is an indication of mobile nature of these metals, with lead (Pb) being the least mobile metal. The result of the leachate characterization are; pH (5.9), total dissolve solids TDS (32 mg/l), total suspended solids TSS (3700 mg/l), dissolve oxygen DO (1.40 mg/l), biological oxygen demand BOD (84 mg/l), chemical oxygen demand COD (214 mg/l), Ca2+ (62.20 mg/l) and Mg2+ (28.00 mg/l). This research is an eye opener to the indiscriminate dumping of hospital waste, as these can be a major source of heavy metals pollution if not properly checked.