The deltaic lobe of Sundarbans is one of the most biologically productive, taxonomically diverse and aesthetically celebrated ecotone of the Indian subcontinent, sustaining the famous mangrove gene pool Due to the existence of highly urbanized cities of Kolkata, Howrah and newly emerging port-cum-industnal complex around the vicinity of this deltaic lobe, the ecosystem is presently under stress A survey on heavy metal (vIz Zn, Cu and Pb) status was conducted in and around this mangrove ecosystem during 2005 with the aim to establish a baseline data The order of heavy metal level in the ambient media (both water and sediment) of the selected stations was Zn>Cu>Pb Highest concentration of these heavy metals was found in the surface water in the months of monsoon, the period characterized by lowest salinity and pH of the ambient aquatic phase In the premonsoon season, the dissolved metal level was lowest The biologically available heavy metals from surface sediment of the selected stations showed a complete opposite picture with highest values during premonsoon and lowest during monsoon. The regulatory roles of aquatic salinity and pH in the process of precipitation-dissolution of the selected heavy metals have been statistically confirmed Significant negative correlations observed between the dissolved metals and sediment metals indicate sharp exchange of heavy metals between the aquatic and sediment compartments under the influence of salinity and pH in the present geographical locale.