Chemical reclamation of crude-oil-inundated soils from Niger Delta, Nigeria

• Published in: Chemistry and ecology 2005-02, Vol.21 (1), p.1-10
• Main Authors: Osuji, L. C., Egbuson, E. J., Ojinnaka, C. M.
• Format: Article
• Language: English
• Subjects: Applied sciences; Crude-oil-inundated soils; Exact sciences and technology; Global environmental pollution; Niger Delta; NPK fertilizer; Oil spillage; Pollution
• ISSN: 0275-7540; 1029-0370
• DOI: 10.1080/02757540412331335988

Crude-oil-inundated soils were collected from the Agbada oil field in the Niger Delta region of Nigeria 2 months after the recorded incidence of oil spillage. The soils were taken on the second day of reconnaissance from three replicate quadrats, at surface (0-15 cm) and subsurface (15-30 cm) depths, using the grid sampling technique. The total extractable hydrocarbon content (THC) of the polluted soils ranged from 1.24 × 10 2 to 3.86 × 10 4  mg/kg at surface and subsurface depths (no overlap in standard errors at a 95% confidence level). Greenhouse trials for possible reclamation were later carried out using 10-100 g of (NH 4 ) 2 SO 4 , KH 2 PO 4 and KCl (NPK) fertilizer as nutrient supplements. Nitrogen as NO 3 -N and potassium were optimally enhanced at 2% (w/w) and 3% (w/w) of the NPK supplementation, respectively. Phosphorus, which was inherently more enhanced in the soils than the other nutrients, maintained the same level of impact after treatment with 20 g of NPK fertilizer. Total organic carbon (%TOC), total organic matter (%TOM), pH, and percentage moisture content all provided evidence of enhanced mineralization in the fertilizer-treated soils. If reclamation of the crude-oil-inundated soils is construed as the return to normal levels of metabolic activities of the soils, then the application of the inorganic fertilizers at such prescribed levels would duly accelerate the remediation process. However, this would be limited to levels of pollution empirically defined by such THC values obtained in this study.