Comparative Analysis of Heavy Metals Concentration in Soil and Vegetable (Vernonia amygdalina) Collected from Two Sampling Sites (Farmland and Dumpsite) and the Effect on Plant DNA

Abstract

Different studies have shown that Vernonia amygdalina is enriched with proteins, fats, fibres, amino acids, minerals vitamins, and carbohydrates but no record yet on the level of heavy metals in Vernonia amygdalina collected from Ojota (dumpsite) and Badagry (control) in Lagos state. Samples of V. amygdalina were collected and analyzed for metals using standard method, while differences in concentrations were analyzed using t-test analysis at level of significance set at p=0.05. The results recorded in mg/100g for the metals content (Cd, Cr, Cu, Pb and Zn) in the plant across the two stations were not significantly different (p>0.05). The Zn in leaf and stem (100.157 ±1.351, 45.743± 3.664) respectively from dumpsite were significantly higher than that of farmland (91.468 ± 2.386, 35.505 ±1.662). Also, Zn content in the root from farmland (73.671 ±2.205) was higher than that of dumpsite (69.515 ± 2.312). All the values of N, P and K recorded in the leaf, stem and roots of bitter leaf from both sites were different significantly (p<0.05). The most frequent nutrient in the leaf, stem and root of the bitter leaf was K, followed by N while the least was P. In contrast, the root contained the highest K, followed by the leaf and then the stem. The DNA band of V. amygdalina from both sites showed no alteration. In conclusion, bitter leaves from both sites were rich in minerals (N, P, and K) though their values were higher at the dumpsites. However, heavy metals content in V. amygdalina at both sites being within standard permissible limits imply it is safe for human consumption.