Role of water hyacinth-mediated phytoremediation in waste water purification at east Calcutta wetland

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.