Pollution (Poly Aromatic Hydrocarbons and Heavy Metals) Evaluation in Soil of Selected Area of Kaduna Towns in Kaduna State

Abstract

The Polycyclic aromatic hydrocarbons (PAHs) and some heavy metals were analysis in the soil samples from urban areas of Kaduna state for their concentration and distribution. Naphthalene, acenaphthylene, acenaphthene, fluorine, phenanthrene, anthracene, fluoranthene, pyrene, chrysene, benzo(a)anthracene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a) pyrene, indeno(1,2,3-cd)perylene, benzo(ghi) perylene and dibenzo(a,h) anthracene were analyzed in three urban soils of Kaduna North, Alegbi and Kaduna South, at 0-15 cm and 16-30 cm depth in wet and dry seasons. After extraction using ultrasonication with hexane and dichloromethane and clean-up, PAHs concentration was measured using gas chromatography. The concentration of all the PAHs obtained ranged between 178.00 mg/g and 787.0 0 mg/g for wet season and 105.10 mg/g and 437.70 mg/g for dry season. The concentrations of PAHs were higher in the subsoil (15-30 cm depth) in the wet season than in the dry season while higher concentrations of all the PAHs were observed in topsoil than subsoil during the dry season. The concentration of PAHs followed the order Kaduna North > Kaduna South > Algabi during the wet season and Kaduna South > Algabi > Kaduna Nort during the dry season. The concentration values of all determined PAHs were below the target value of 1000 mg/g stipulated by Department of Petroleum Resources. The Cd, Cr, Cu and Pb levels in the soil from the study sites were higher than the corresponding control values. The degree of pollution of various metals using the graded standard of Nemero pollution index varied. The concentrations of the metals were found to be above the recommended limits given by USEPA/WHO. This could pose risks and hazards to human and the ecosystem through direct ingestion of contaminated soil