Soil characteristics and nutritional parameters of Telfairia occidentalis Hook around auto-mechanic workshop in Ibesikpo-Asutan, Akwa Ibom State, Nigeria

Soil characteristics and mineral nutrients parameters of Telfairia occidentalis Hook around auto-mechanic workshop in Ibesikpo- Asutan, Akwa Ibom State, were investigated with the aim of ascertaining the level of petroleum oil contamination on the site. Soil samples were collected (0-20cm depth) from four (4) sampling locations (M0, M1, M2, and M3) in triplicates, giving a total of twelve (12) representative samples. M1, M2, and M3 were sampling units at the auto-mechanic workshop, while M0 sampling unit was the control treatment (an area outside the auto-mechanic workshop). Soil samples obtained from M1was 15m away from the auto-mechanic workshop and with a corresponding distance from M1 to M2 as well as M2 to M3. Leaf samples of T. occidentalis were obtained around the auto-mechanic workshop using the corresponding distance with the soil samples. Complete randomized block design was used as research design. The pH of soils around the auto-mechanic workshop (M1, M2 and M3) was slightly acidic (4.30±0.36, 4.50±1.32 and 4.70±0.52, respectively), with values approaching neutral status as the distance from contamination site increased. The values of pH at the contamination site (M1-M3) were significantly lower (P < 0.05) than that of the control (M0- 5.20±2.10).The soil nitrogen and phosphorus levels decreased considerably with increase in carbon contents in soils around the auto-mechanic workshop (M1-M3).The contents of calcium, magnesium and potassium at the contaminated site were significantly lower (P < 0.05) than those of the control site (M0). Conversely, the heavy metal (zinc, copper, iron and lead) contents in soils of the contaminated site were significantly (P < 0.05) higher than those of the control site (M0).There were marked variations in contents of Ca, P, N, Mg, K, Fe, Pb and Cu in the tissue of test crop between the sampling locations (M0, M1 M2 and M3), with values of P, Fe, Pb and Cu being significantly (P< 0.05) higher than those of the control site (M0), while the Ca, N, Mg and K contents in the test crop tissue weresignificantly (P< 0.05) lower than those of the control site (M0). This study clearly revealed that petroleum oil wastes affected both soilchemical propertiesand contents of mineral element in the tissues of T. occidentalis.