Anotace:
Assessment of the uptake and bioaccumulation of diverse hydrocarbon compounds within internal tissues by selected food plants artificially exposed to bioremediated crude oil-contaminated soils was carried out. Three bioremediated crude-oil contaminated soils of different fallow ages (6-, 12-, and 18- months after certified remediation protocols) and an uncontaminated soil were collected and designated as 6m-AB, 12m-AB, 18m-AB and control respectively. Total petroleum hydrocarbons (TPH) and intermediate metabolites of degradation in soil samples were determined in the dry and wet seasons using Gas Chromatography – Mass Spectrophotometer. Telfairia occidentalis, Zea mays, Cucumis sativus, and Abelmoschus esculentus were used to assess safety of crops grown on test soils by monitoring the bioaccumulation of chemical residues in their tissues. Baseline TPH contents in various soil samples were 161.25 mg Kg-1 (6m-AB), 51.72 mg Kg-1 (12m-AB), 91.50 mg Kg-1 (18m-AB) and below detectable level in the control soil. A myriad of organic compounds emanating from degradation of petroleum compounds and including toxic and carcinogenic metabolic intermediates like trifluoromethyltrimethylsilane, phthalate esters and halogenated aliphatics were detected in bioremediated soil and also in tissues of the plants grown on the bioremediated soils. Higher bioconcentration factors for accumulated organic compounds were obtained during the wet season for all plants with Telfairia occidentalis having the highest bioconcentration factor in both wet and dry seasons. Results obtained provide evidence of contaminant transfer from these bioremediated soils to plant tissues and suggest the need for adequate evaluation of chemical residues in remediated soils before utilizing such sites for farming to ensure safe crop production.