Abstract

All forms of mercury are toxic to plant and animal life. Its use in Chlor-alkali industry as an electrolyte, its discharge into the environment along with effluent and solid waste collected from the effluent canal and dumped near water bodies is alarming. The effluent and solid waste contained significant amount of mercury. Plants around the effluent canal, effluent soaking pond and solid waste dumping site absorbed and accumulated mercury significantly. The experimental alga absorbed and accumulated significant amount of mercury by biosorption and removed significant quantity of mercury by absorption and adsorption. Mercury in the effluent significantly affected the growth (optical density and dry weight), photosynthetic efficiency (pigments) and productivity (PR, RR, GPP) of exposed alga, Westiellopsis prolifica during exposure. This toxicant, mercury contained effluent showed stimulatory effect at maximum allowable concentration and inhibitory impact at higher concentrations of the mercury contained effluent indicating dual behavior of mercury with the alga. At MAC value, the alga grows well and the toxicant could not affect any of the metabolic processes and removes significant amount of mercury from the mercury contaminated effluent. This alga removed mercury by adsorption of Hg on the outer wall and over gelatinous sheath; by absorption from the surrounding environment and accumulating in the cells. The secondary metabolite extract of 4 economically important medicinal plants did not show any reclamation value. However, this alga can be recommended for phycoremediation of mercury contained wastes.

Keywords: Chlor-alkali industry, Effluent, Mercury, Westiellopsis, Growth, Pigments, Photosynthetic efficiency, Plant extract, Productivity, Phytoremediation