Leaves of Higher Plants as Indicators of Heavy Metal Pollution along the Urban Roadways

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Author(s) A. P. Deepalakshmi | H. Ramakrishnaiah | Y. L. Ramachandra | N. Naveen Kumar
Pages 340-346
Volume 3
Issue 6
Date June, 2014
Keywords heavy metals, Ageratum conyzoides, ICP – OES, bioindicator, vehicular traffic, higher plants.

Plants are hitherto regarded as sinks for pollutants and can accumulate higher concentration of heavy metals in urban environment. The concentrations of Pb, Cu, Cd and Zn were determined to assess the impact of automobiles on heavy metal concentrations in plants growing along the roadways. Inductively Coupled Plasma – Optical Emission Spectrometer (ICP – OES) was used to estimate heavy metals concentrations in plants. Concentrations of Pb, Cu, Cd and Zn were significantly higher in plants growing at polluted sites when compared to their control counterparts. The Pb levels of plants at polluted site varied from 46.2 - 84.9 µgg−1, highest being noted in Ageratum conyzoides. The species Ageratum conyzoides showed higher levels of Cu and Zn at polluted site. The mean concentration of cadmium remained relatively low when compared to other metals, with highest of 10.5 µgg−1 in Cynodon dactylon. The increase in heavy metal content in plants across polluted sites showed positive correlation with traffic density. With higher levels of Pb, Cu, Cd and Zn Ageratum conyzoides can be considered as multi metal indicator.

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