Performance of Phaseolus vulgaris L. in a soil contaminated with spent-engine oil

Phytoremediation is an alternative low cost approach for in situ treatment of polluted soils. This study evaluated growth and biochemical composition of Phaseolus vulgaris as influenced by spent engine oil contaminated soil. The experiment was conducted in a pot during the 2005 cropping season. The soil received (0% (control), 1, 5 and 10%) v/w of oil and was completely randomized with three replications per treatment. Significant treatment effects were observed in plant height, number of leaves and dry weight. However, plant height 42 days after planting (DAP) and dry weight 28 DAP were not significantly different (p<0.05). The control dry weight accounted for greater percentage of the total dry weight recorded in each of the sampling regimes relative to other treatment. There was about 1.3, 1.4 and 1.6fold yield reduction as concentration of spent oil increased (1-10%) respectively. This study established that P. vulgaris was growing under stress as indicated by the dose-dependent significant increase in protein content relative to control and low chlorophyll content of the plant with treatment. There is evident that P. vulgaris can sustain growth in an oil polluted soil and a good candidate for phytoremediation.