The Effect of Crude Oil Spill on the Ascorbic Acid Content of Some Selected Vegetable Species: Spinacea oleraceae, Solanum melongena and Talinum triangulare in an Oil Polluted Soil

Abstract

The research work focused on the effect of oil spill on some certain soil physicochemical parameters and the concentrations of vitamin C (Ascorbic acid) of three leafy vegetable species at pre and post pollution periods. The vegetable species involved in the study included: Spinacea oleraceae (Spinach), Solanum melongena (Eggplant) and Talinum triangulare (Water leaf) in an oil polluted soil. The ascorbic acid contents of the species pre and post pollution periods expressed in mg/100 g of samples were as follows: Spinacea oleraceae, 1057.1±0.1 and 635.8±0.2; Solanum melongena, 880.0±0.0 and 712.8±0.1 while the values for Talinum triangulare were 550.0±0.0 and 350.0±0.0 respectively. The physicochemical parameters of the polluted and unpolluted soils were also determined and result indicated that pH (4.4-5.3), moisture content (4.23±0.2-7.99±0.1%), bulk density (1.28±0.1-1.36±0.2 g/cm³), particle density (2.05±0.1-2.35±0.1 g/cm³) and porosity (37.56±0.0-42.49±0.1) were higher in unpolluted than in polluted soil, while sodium (Na, 94.1403±0.01-31.5517±0.01 mg/L), potassium (K, 188.0226±0.0-74.1663±0.01 mg/L), organic carbon content (1.93515-1.21695%) and percent organic matter (3.34587±0.0-2.10410±0.01), growth rate of the different vegetable species: Spinach olereceae (0.24±0.02-0.12±0.0), Solanum melongena (0.30±0.1-0.15±0.0), Talinum triangulare (0.29±0.11-0.12±0.2) and plant biomass were highly decreased. Students t-test at 95% confidence level or at 5% level of significance (p<0.05), showed significant difference between the ascorbic acid concentrations of the test samples before and after pollution periods. Results from the study indicated that oil pollution affected the growth rate, the vitamin C content of the vegetables, the nutrient content, the chemical composition of plants and the physicochemical parameters of the soil.