Mangifera indica AS BIOINDICATOR OF METAL POLLUTION ALONG MAJOR ROADSIDES WITHIN AKWA IBOM STATE, NIGER DELTA REGION OF NIGERIA

Leaves of Mangifera indica with significant aerial exposure at major roadsides were collected from seven (7) local government areas namely: Ikot Ekpene; Ibiono Ibom, Uyo, Ukanafun, Nsit Ibom, Eket and Ibeno within Akwa Ibom State. At each location, similar samples were also obtained at a distance of more than 25 km from the roadside and used as Control. These samples and their Controls were digested and analyzed spectrophotometrically for the levels of Iron (Fe); copper (Cu); zinc (Zn); lead (Pb); cadmium (Cd); nickel (Ni) and chromium (Cr). Results obtained indicated that levels of these metals in roadside samples were below their acceptable limits for plants except that of Pb and Cd. This study also showed that, mean concentrations of all the metals evaluated in samples from roadside were much higher than their corresponding levels in their Controls indicating considerable inputs from vehicular emissions. Consequently, enrichment factor analysis disclosed that all the elements analyzed for were more of artificial source than natural except Zn. In both samples from roadside and Controls, iron recorded the highest metal level amongst all metals assessed except Zn recorded at Ibeno. Principally, this study has shown that vehicular emissions can contribute significant amounts of toxic metals into our environments.