The physico-chemical analysis of the effluent at three points of the effluent canal showed significant variation in different parameters. The leachate chemicals leaching from the storage tank into Rushikulya river showed very high values. This might be due to aerial drying and surface evaporation of water from the storage tank enriching the chemicals in the storage tanks. The effluent analysis at different time periods indicate a great variation in parameters. The 2013 reported data, indicated increase in mercury concentration in the effluent to 3.16+0.45 mg l-1 when compared to the report of 1996, however, the mercury concentration decreased to 0.96 0.18 mg l-1 in February, 2016. The decrease in mercury concentration was due to change in technology as no mercury was discharged. Whatever mercury was available was due to past deposition and present leaching from deposition, as huge amount of mercury was discharged in to the environment (mostly in to Rushikulya river and Rushikulya estuary) by the industry in the past 50-52 years. Residual accumulation of mercury leading to bioconcentration was marked in all the 11 fishes tested. The control fish did not show any residual mercury. However, all these fishes showed higher level of residual mercury. It was also noted that the collected dead fish showed higher residual mercury level in their body. It can be inferred that prolonged exposure to mercury leads to accumulation and bioconcentration of mercury in fish body. When the residual mercury increases significantly that might lead to fish mortality.