Accumulation of metals in naturally grown weeds (aquatic macrophytes) grown on an industrial effluent channel

The ability of seven hyperaccumulator macrophytes which grow naturally in the heavy metal contaminated channels of three different industries (Hindustan Aeronautical Ltd., Eveready Ltd., and Scooter India Ltd.) to accumulate heavy metals was recorded. All these industries use electroplating processes in their manufacturing and are located in the inner area of Lucknow City, U.P., India. Of the three industries monitored, effluent released from Eveready Ltd. contained the highest concentration of heavy metals. In general, accumulations of heavy metals depend upon the plant species and the metal concentration in the media. All plant samples showed heterogeneous metal accumulations, except for Fe or Cd. It was observed that some plant species accumulated high level of metals, e.g., Eichhornnia crassipes for Fe (4052.44 mu g/g), Mn (788.42 mu g/g), and Cu (315.50 mu g/g), and Spirodela polyrhiza for Cd (12.75 mu g/g), Pb (20.25 mu g/g), and Cr (128.27 mu g/g), even when the metal concentrations were not high in the effluent. In summary, these two plants were found to be the best accumulators at each contaminated site. The results will be helpful in the selection of plant species which can be used as bioaccumulators or bioindicators.