The present piece of work was designed to study the effect of the Basil and Calotropis extract on the SWE of a chlor-alkali industry on the blue-green alga, Westiellopsis prolifica, Janet and to find out a possible use of plant extracts (secondary metabolites) for reclamation of SWE of the chlor-alkali industry. A graded series of concentrations of the SWE was prepared and a pure culture of the alga, Westiellopsis prolifica, Janet was inoculated to find out the lethal concentration value or percent survival value. From this, the lethal concentration values were determined. The below three concentrations were selected- SWE LC00=0.1 ml/50 ml culture; SWE LC10=0.2 ml/50 ml culture; SWE
LC50=0.3 ml/50 ml culture for future experiments. No significant morphometric change was noticed in the exposed BGA. At higher concentrations of the SWE, bleaching of the filaments was marked. In other sets no bleaching was marked. Stimulation of growth was marked at lower concentration of the toxicant, as all growth parameters showed higher values, when compared to the control value. The data indicated that during 15th days of exposure, growth was restricted and all the pigments disappeared in the SWE when compared to standard control. The dry weight of the exposed alga showed significant increase in plant leaf extract applied cultures when compared to control and SWE exposed cultures. Significant increase in chlorophyll content was recorded in exposed cultures where plant leaf extract was applied when compared to the control value. Significant increase in phaeophytin and carotenoid content was recorded in plant leaf extract treatment, when compared to the control value. The changes noted indicated that the plant leaf extract detoxifies the mercury contaminated wastes (the wastes might be the solid waste or SWE or effluent). From the present experiment, it can be concluded that the cyanobacterium, Basil and Calotropis plant leaf extract can be applied in combination to the mercury contaminated wastes for total reclamation of the mercury contained wastes.