ABSTRACT

The effect of spent engine oil on germination and heavy metals of some tropical legumes was investigated three legumes, mung bean, winged bean and lima bean were planted in soil stimulated with spent engine oil pollution at rates of 50ml/3kg, 100ml/3kg, 100ml/3kg, and 250ml/3kg, and allowed to grow for 2 months after which growth performance and heavy metals content of the plants were determined. Results obtained showed that the oil pollution affected the legume plants adversely. Germination was r&duced from 100% in the controls of the three legumes to varied percentage of germination in the ranges of 11.1 % - 88.9%. Toe vegetative indices showed reduction in the plant sizes in the oil pollution soils. Plant length in the unpolluted soil ranges· from 61.7° ± 0.58 - 16.13° ± 0.58 in mung bean, winged bean and lima bean. The plant length in the polluted soil ranges from 2.43° ± 0.58- 24.33° ± 0.58. Toe leaf area result ranges from 338.0 ± 3.00 - 1690.3° ± 11.15 and was significantly different at (P<0.05) in the polluted soil reduction were recorded in the number of leaves ranges from 2.00° ± 0.0 - 23.33° ± 0.58 in oil polluted soil. Toe oil pollution did not affect the physical properties of soil as all soils were with the textual class as all soil's were with the textual class of sandy, clay and loam. But the chemical and nutrient status change due to pollution with pH reduction from 5.93° ±0.12 - 5.00° ± 0.17, organic carbon increase from 1.50° ± 0.03 - 1.29 1 ± 0.02 and organic matter increase from 2.22° ± 0.04 - 2.58 1 ± 0.06. Toe exchangeable cation also reduced from 0.88± 0.03-0.47± 0.01, 0.37° ± 0.12- 0.19 ± 0.02 (mg), 0.15° ± 0.01 ± 0.11°± 0.01 (K) and 0.43° ± 0.04- 0.30° ±0.01 (Na). The total nitrogen reduced from 0.25a ± 0.01- 0.21°± 0.02. In winged bean, N; increased from 4.29P± 0.04.- 5.95± 0.01 in all plant grown in oil polluted soil and 2.95° ± 0.01 in the control soil, while the increase in control of mung bean was 3.20° ± 0.03 in control against 6.05'± 0.01- 4.30 ± 0.08 in oil polluted soils. While the increase in control of mung bean was 3.20° ± 0.02- 4.38 ± 0.03 in oil polluted soil and 3.44 ± 0.03 in the control soil. Similarly increases were recorded in cu, cd, fe, Mn, and Zn and the trend was the same but the levels different in the different legume plants. It was observed that oil pollution had adverse effect on the plant which may accumulate the heavy metal and pass same into the food chain with potential to cause harm to consumers.