The East Calcutta Wetlands, a Ramsar site at the eastern fringe of the city of Calcutta, India, is contaminated by composite industrial wastewater throughout the year. The present study investigated the sequestration of different elements, namely, Ca, Cr, Mn, Fe, Cu, Zn and Pb, in the different parts of two common wetland plants: water hyacinth (Eichhornia crassipes) and common arum (Colocasia antiquorum) grown in the contaminated wetland area. The 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, as their ability to grow in such areas is unique. Plants were collected from the major wastewater-carrying canal and the wastewater-fed fishpond area. Atomic absorption spectrophotometry (AAS) was employed to study the elemental concentrations in the plants. It has been observed that concentrations of elements in the ambient environment play a vital role in the accumulation of the elements within the plant biosystems. Roots were found to be the major accumulating part for both plant species collected from each of the sites, with variations in metal accumulation within the plant body. Energy-dispersive X-ray microanalysis study of the roots of both species from the contaminated sites showed a diverse distribution pattern of elements along the root. Variation of elemental concentrations within the root zones for water hyacinth and common arum might be an indicator of their ability to concentrate metals in the aerial part of the plant.

Land Contamination & Reclamation, 15 (4), 437-452 (2007)