Eco-phytochemical Studies in Selected Food Crops Cultivated in a Small-scale Oil-refining Area of Ikot Oborenyin, Akwa Ibom State, Nigeria

Aims: The study aimed at assessing the uptake of essential nutrients by tuber crops from soils at Ikot Oborenyin where small scale oil refining occurs.

Study Design: Experimental study was employed to achieve the aim of the study.

Place and Duration of Study: The study was conducted at the Department of Chemistry and the Department of Soil Science, University of Uyo, Nigeria between October, 2012 and May, 2013.

Methodology: Soils and tuber crops were collected from crude oil refining and non-oil refining areas using composite sampling. Soil pH, electrical conductivity, organic matter (OM), cation exchange capacity, particle size distribution and exchange acidity were analysed using standard protocols. Levels of nitrates, nitrites, sulphates and phosphates were measured using UV-Visible spectrophotoscopy. Transfer factors and soil contamination indices were computed. Data analyses were done using Pearson’s correlation coefficient method.

Results: Results from the study revealed that the soils from the oil refining sites had some of their properties altered; they were loamy sand in texture, slightly acidic with high organic matter contents. The OM content was higher (P< 0.05) in oil refining sites. Trends for the concentration of anions in plants parts were: leaves ˃ stems ˃ tubers. The levels of anions from every parts of the plant analyzed showed that plants from the negative control site were higher in anions content (P<.05) compared to plants from the test site. In contrast, anions content were higher in the test site compared to the negative control site of the soil samples. Correlation analyses indicate different sources of input of anion to soils.

Conclusion: The study showed the inhibition of uptake of some important nutrients in the soil by plants as a result of crude oil presence. Transfer factor values show that the plant species are poor accumulators of sulphates, nitrites and nitrates but are efficient at bio-accumulating phosphate ions. The information generated in different crops cultivated under control and oil spill mining areas can be used for improvement of soil status and crop production. The data generated thus is useful for future action plan to grow suitable crops and soil correction factor Remediation programs are advocated for the communities.