Heavy metal contamination in leaves of Mangifera indica around a coal fired thermal power plant in India

Abstract

The aim of this study is to evaluate the differences in the bioaccumulation of some elements in Mangifera indica tree leaves grown around a coal fired Thermal Power Plant (affected areas) and in other areas (control) 25 km away from Thermal Power Plant (TPP). Toxic group of metals (Pb, Cd and Cr) in an average displayed higher levels (28.0, 2.4 and 3.2 ppm for Pb, Cd and Cr respectively) in plants grown in affected sites with distinct temporal and spatial variation in comparison to samples in control areas (0.09 to 2.2 ppm for Pb, 0.01 to 1.1 ppm for Cd and 0.01 to 0.65 ppm for Cr). Such types of variations were not encountered significantly in cases of the essential metals (Cu, Zn, Ni and Fe). Strong positive correlation (P > 0.05) between the pairs of toxic metals in affected sites could be associated with their similar anthropogenic source. This resulted in higher contamination factor (CF > 6) of the toxic metals in plant leaves grown in the periphery of the TPP. The ash contamination from TPP might play an active role for this metal enrichment in plant leaves. The leaves of this plant could be classified as considerable degree of heavy metal pollution during the year and this might affect the productivity of this important commercial plant to a great extent. The winter months might represent the best sampling period for evaluation of the suitability of this plant as bio-indicator of metal pollution. Key words: Bioaccumulation, degree of contamination, heavy metals, Mangifera indica, spatial and temporal variation.