East Calcutta Wetland (ECW) is an example of wise use of cities solid and liquid waste through integrated resource recovery, mainly for pisciculture, vegetable as well as paddy cultivation and manure production. Amaranthus caudatus, Amaranthus blithum and Spinacia oleracea grown at ECW were analyzed for their accumulation of elements using Energy Dispersive X Ray Fluorescence (EDXRF) and compared to those grown in south eastern parts of West Bengal (Midnapur). The objective was to analyze the health hazard, if any, underlying the use of wastewater and solid waste for cultivation of green leafy vegetables at ECW. The following results were obtained upon comparing the data collected from the two different sites: (a) higher accumulation in ECW grown plants of elements like Ca, Cu and Pb in Amaranthus caudatus; of Ca in Amaranthus blithum; of Cl and Cu in Spinacia oleracea, (b) for the same species grown in non-ECW site, higher concentration of elements like Mn and Fe in Amaranthus caudatus; of Cl, Mn and Br in Amaranthus blithum; of Ca, Mn, Fe and Br in Spinacia oleracea. The net consumption of the aforementioned elements per person per day was calculated and found to be much below the Recommended Dietary Allowance (RDA) levels in all cases. Thus the vegetables grown out of integrated resource recovery mechanism at East Calcutta Wetland appear to be safe for human consumption. This further corroborated by the healthy appearance of these vegetables. This result has profound implications of far reaching significance for environmental management and health economics.

The current study is on East Calcutta Wetland (ECW) which is a model for multi-use resource recovery system with activities like pisciculture and agriculture. The entire city's soluble waste is disposed into the raw sewage canals which finally drains into the shallow, flat bottom fish ponds called Bheri. These sewage fed fisheries act simultaneously for the purification process like removal of heavy metals, coliform reduction as well as fish production at a commercial scale. The fishes from these Bheri are analyzed for the extent of metal accumulation in them as compared with those collected from the fresh water ponds around Calcutta. This comparative study was done to access the risk involved, if any, in fish cultivation and its subsequent consumption from these wastewater fed fisheries. Two types of commonly consumed fishes were chosen for the study namely Labeo rohita and Cirrhinus mrigala. Analysis of elements like P, S, Cl, K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb, Sr and Pb was done by Energy Dispersive X Ray Fluorescence (EDXRF) in order to quantify the level of accumulation. The analysis inferred that elements like Cr, Cu, Rb, Pb shows accumulation in substantial amount in both type of fishes collected from the sewage fed as well as freshwater sources. The uptake of these fishes by human population thereby causes the consumption of these elements in relatively higher level as compared to the Recommended Dietary Allowance (RDA). Thus consumption of waste water cultivated fishes pose no additional health hazard. The accumulation of these metals in fishes from both Bheri as well as fresh water pond put forth a plausible action of diverse microscopic population and certain geochemical factors acting beneath the phenomenon of sedimentation as well as biomagnification of metal in the fish pond and their subsequent uptake in the aquatic food chain

This research note is an attempt to understand the role of water hyacinth vis-à-vis metal removal mechanism operating in ''Bheris'' -the shallow flat bottom waste water fed fisheries, which are unique ecosystems found in West Bengal, India. This study approaches the question by analysing the extent of heavy metal accumulation in water bodies of varied origin and geographic location in and around east Calcutta wetland as well as in different parts of water hyacinth obtained from these locations. Wastewater fed fish ponds are found to have lesser metal accumulation compared to rainwater ponds. This may be partly due to strong bioremediation operating in the wastewater ponds as a result of the existing microbes as well as plankton community. The phenomenon of heavy metal accumulation at a site thus depends on the soil condition, ground water level and the biotic population inhabiting that site.