Assessment of Heavy Metals Contamination in Soil and Plant (Talinum triangulare) Leaf around Selected Industrial Areas in Ogun State, Nigeria

Abstract

Heavy metal accumulations in plant and soil from anthropogenic sources with subsequent consequences constitute major environmental problem. This present study investigated the pollution load of heavy metals in the soil and plant from selected industrial estates, Ogun State, Nigeria. Twenty soil and plant samples were collected from four selected industrial areas in Agbara, Sango-ota, Ewekoro, and Sagamu Ogun State, Nigeria. Also, five soil and plant samples were collected from Epe town, located in the outskirts of Ogun where there are no industrial activities to serve as control. The concentration of selected heavy metals in the soil and plant samples were determined by atomic absorption spectrometry. The mean concentration of heavy metal in the soil shows Fe ranged from 50.00 to 1964.00 mg/kg, Zn ranged from 136.00 to 1862.80 mg/kg; Cu ranged from 4.12 to 122.40 mg/kg, Cd ranged from ND to 12.48 mg/kg, and Mn ranged from 16.76 to 60.60 mg/kg. Also, mean concentration of Fe in the vegetable samples ranged from 118.00 to 579.20 mg/kg, Zn ranged from ND to 1687.00 mg/kg, Cu ranged between 5.72 to 32.16 mg/kg, Cd ranged from 1.12 to 12.16 mg/kg while Mn ranged from 13.00 to 32.60. Analysis of variance revealed significant (p<0.05) variation in the concentrations of the heavy metals in soil and plant samples among the sites which is an indication of extent of metal contamination. Positive correlation was found in some of the metals in soils and plants samples indicating common contamination source. Zn, Cu and Cd concentrations in the soils from some of the locations exceeded WHO permissible limit. The impact of industries on surrounding environmental media was observed, it is therefore necessary for the authorities to enforce stricter measures on the release of contaminants into the environment by industries to forestall health crisis.