Phytoremediation of Pb, Zn, Fe, and Mg with 25 wetland plant species from a paper mill contaminated site in North East India

In order to assess the potential of wetland plants to remediate metals from a paper mill effluent contaminated wetland site in Northeast India, 25 abundant plant species belonging to 15 different families, soil, and water samples from the sites were tested for Pb, Zn, Mg, and Fe by atomic absorption spectrophotometer. The results showed that metal accumulation by wetland plants differed among species and tissues. Plants thrived in high Pb, Zn, Mg, and Fe which indicated their tolerance. According to the criteria used for selecting plants for phytoremediation such as high metal tolerance, short life cycle, wide distribution, large shoot biomass and translocation factor (TF) > 1; five species each were Mg and Fe accumulators, nine species were Pb accumulators and, eight species were Zn accumulators and the rest were excluders. Alternanthera sessilis was the only plant species that had TF> 1 for all the four metals. The study indicated great promise for phytoremediation, as these accumulators could be used in future for practical phytoremediation approaches and reduction of the risk from harmful metals to human health.