Evaluation of Heavy Metals Ions in Calopogonium mucunoides, Manihot esculenta, Psidium guajava and Mangifera indica Plant Species Within Quarry Site, Akamkpa, Nigeria and Phyto-remediation Potential

Abstract

The exploration of mineral resources like quarrying is having a serious negative impact on the ecosystem. Phytoremediation has become one of the eco-friendly mitigation measures used to revegetate heavy metal polluted soil. This study evaluates the levels of heavy metals in selected plant species (Calopogonium mucunoides, Manihot esculenta and Psiduim guajava L and Mangifera indica L with potential for phyto-remediation within SEEPCO Quarry site, Obung, Akamkpa, Nigeria. The plants leaves were harvested with secateurs within the vicinity (0km) of the quarry while the control sample was harvested (2.5km) away from any quarry. Two (2) soil samples, each weighing 1 kg, were scooped using an auger from a depth of 0–15 cm at a distance of 0km and 2.5km (control) away from the quarry crushing area. Heavy metals content in the soil and plant samples were determined using Atomic Absorption Spectrophotometric (AAS) method.  Results: The results showed that Nickel concentration in Calopogonium mucunoides, Manihot esculenta C., guava Psiduim guajava L. and Mangifera indica L  harvested in the quarry site (0km) had concentration of (4.58± 0.02, 9.75± 0.01, 12.75± 0.00, 24.76± 0.00) mg/kg respectively and was higher in concentration than the samples harvested from the control site (2.5km) with (1.82± 0.02, 4.18± 0.01, 2.15± 0.04, 7.23± 0.01) mg/kg respectively.  The results also showed that all heavy metals in the soil samples investigated (Nickel, cadmium, Zinc, Lead and copper) at the sampling point of (0km) recorded higher levels of heavy metal (3.15± 0.01, 7.95± 0.02, 20.13± 0.02, 31.66± 0.03, 89.89± 0.03) mg/kg respectively than those at the control site (2.5km) with (2.11± 0.00, 1.23± 0.01, 11.95± 0.02, 4.76± 0.00, 80.45± 0.01) mg/kg respectively. This suggests that the concentration heavy metals in the plants and soil decline as the distance from the quarry increases. The high concentration of heavy metals in the parts of the plants may be due to the absorption/ phytoremediation ability of the plants.