Pages 128–133
Abstract
Research summary supplied by the authors
Wetlands are cardinal ecosystems yet utterly neglected in most parts of the globe. They are one of the important sources of environmental oxygen and replenish subsoil water and nutrients through retention & reuse. Kolkata, India, has a vast wetland area, the East Calcutta Wetlands (ECW 22°25’ N – 22°40’ N and 88°20’ E – 88°35’ E) located at the eastern fringe of the city, that cleans the city’s wastewater and uses waste nutrients productively in producing fish and vegetables, besides other ecological benefits. The comprehensive years-long examinations on ECW were carried out by using instruments like AAS, PIXE, XRD, EDAX, CHN, SEM, TEM, IEM, AFM, flow cytometry, fluorescence microscopy, etc. to study i) the sequestration of different elements (viz., Ca, Cr, Mn, Fe, Cu, Zn, and Pb) in water and soil of wastewatercarrying canals, pisciculture ponds, & agricultural lands; ii) metal uptake by plants grown for floriculture and agriculture, naturally occurring wetland plants, and fish species; iii) the process of metal amelioration at the tissue level (including toxic responses of fish tissue, if any). The study indicated the cumulative accumulation of metals in sediments from water and thus comparatively lower uptake by the organisms, where wetland plants in ECW play a crucial role in bioremediation of metals, and fish tissues resorted to metal accumulation by methylation of the metals using metalloproteins (metallothionein). The study reveals that ECW, a Ramsar Site (no. 1208), though decimated by >37% due to anthropogenic interventions, naturally converts composite wastewater, generates wealth, and provides many ecological benefits that our city of Kolkata has been enjoying for over the last hundred years.