The chlor-alkali industry M/s. Jayashree Chemicals Pvt. Ltd., is situated at Ganjam, was under study, to assess the impact of mercury discharged from a chlor-alkali industry on environment and biodiversity at the contaminated site at Ganjam, Odisha. The analysis of the effluent collected from two contaminated sites showed significantly high level in all parameters tested and the most important being the mercury level. It was expected that no mercury will be found after the change in technology by the industry but unfortunately mercury presence was detected. It was opined that the available mercury was due to mobilization of mercury from sediments to the effluent as sediments were found contain the previously discharged mercury. The solid waste also showed very high level of mercury. The plants collected during 2011 showed significantly high level of residual mercury. However, the mercury level dropped significantly in2016. High level of residual mercury in few perennial plants not consumed by grazers is not a concern but the very availability of mercury in plant warrants attention. The residual mercury affected the pigment content of the plant leaves collected from the contaminated environments and the values were significant when compared to respective control values. The plant pigments significantly depleted with the increase in mercury concentration and it was also opined that mercury is responsible for such a drastic depletion in pigment content. The comparison of2016 values with 2011 values indicated that the mercury contamination was at its peak in 2011 and the contamination decreased in2016, which is a positive sign. The total removal of solid waste from the area and transported to a distant place for use in construction of roads is a good sign for Ganjam area but a bad sign for those places where these solid wastes will be dumped. These wastes contain high level of mercury and will contaminate the air, water bodies by leaching and land mass by leaching and rain run off water.