Evaluation of some heavy metals and physicochemical properties of public refuse dumpsites in Nsukka metropolis, Nigeria

摘要

This study assessed some physicochemical properties and heavy metal contamination of four major dumpsites in Nsukka metropolis. Soil samples were collected randomly at depth of 15 cm. Physicochemical properties were determined. Levels of lead, chromium, iron, manganese, zinc, cadmium, and copper were analyzed using atomic absorption spectrophometer (AAS). Soil pH ranged 5.68-6.82, temperature 25.30(-)29.67 degrees C, and moisture 2.23-7.66%. Soil particle size distribution had higher percentages of sand 40-55% followed by silt 15-35% and clay 10-30%. Average levels of Pb, Cr, Fe, Mn, Zn, Cd, and Cu from the dumpsites ranged from 0.08 +/- 0.04 mg/kg to 1.40 +/- 0.15 mg/kg, 0.17 +/- 0.09 mg/kg to 1.66 +/- 0.87 mg/kg, 14.05 +/- 5.13 mg/kg to 21.08 +/- 0.01 mg/kg, 4.47 +/- 0.54 mg/kg to 16.83 +/- 0.80 mg/kg, 9.10 +/- 3.05 mg/kg to19.33 +/- 0.12 mg/kg, 0.02 +/- 0.01 mg/kg to 1.15 +/- 0.30 mg/kg, and 0.77 +/- 0.26 mg/kg to 7.29 +/- 2.65 mg/kg, respectively. Heavy metal profile in the dumpsite soils was Fe Zn Mn Cu Cr Pb Cd. Heavy metal load by dumpsites was Obimo Ikenga Hotel UNN Obukpa. All the heavy metals evaluated except Fe increased as pH, temperature, and sand contents of dumpsite soil increased. Retention of Fe by soil was positively related to its clay contents. The values of heavy metals in soils from the dumpsites were far below the permissible limits set by European Regulatory Standard (EURS STD), US Environmental Protection Agency (USEPA), and Federal Environmental Protection Agency (FEPA) for standard soil. The dumpsites require no remediation as at the time of this study.