A study on the phytoaccumulation of waste elements in wetland plants of a Ramsar site in India

Some wetland plant species are adapted to growing in the areas of higher metal concentrations. Use of such vegetation in remediation of soil and water contaminated with heavy metals is a promising cost-effective alternative to the more established treatment methods. Throughout the year, composite industrial effluents bringing various kinds of heavy metals contaminate our study site, the East Calcutta Wetlands, a Ramsar site at the eastern fringe of Kolkata city (formerly Calcutta), India. In the present study, possible measures for remediation of contaminated soil and water (with elements namely, Ca, Cr, Cu, Pb, Zn, Mn, and Fe) of the ecosystem had been investigated. Ten common regional wetland plant species were selected to study their efficiency and diversity in metal uptake and accumulation. Results showed that Bermuda grass (Cynodon dactylon) had the highest total Cr concentration (6,601 +/- 33 mg kg (-aEuro parts per thousand 1) dw). The extent of accumulation of various elements in ten common wetland plants of the study sites was: Pb (4.4-57 mg kg (-aEuro parts per thousand 1) dw), Cu (6.2-39 mg kg (-aEuro parts per thousand 1) dw), Zn (59-364 mg kg (-aEuro parts per thousand 1) dw), Mn (87-376 mg kg (-aEuro parts per thousand 1) dw), Fe (188-8,625 mg kg (-aEuro parts per thousand 1) dw), Ca (969-3,756 mg kg (-aEuro parts per thousand 1) dw), and Cr (27-660 mg kg (-aEuro parts per thousand 1) dw) indicating an uptake gradient of elements by plants as Ca > Fe > Mn > Cr > Zn > Cu > Pb. The present study indicates the importance of identification and efficiency of metal uptake and accumulation capabilities by plants in relation to their applications in remediation of a contaminated East Calcutta Wetland ecosystem.