The solid waste extract prepared from the solid waste of a chlor-alkali was taken and toxicity study was conducted with blue-green algae, Westiellopsis prolifica, Janet., Anabaena cylindrica, Lemm, Nostoc sp. and Oscillatoria sp. Experiments were conducted in concentrations selected from toxicity testing. Mercury content analysis indicated that the Waste Extract (WE) contained 3.24, 11.52, 25.34 ?g of mercury in the culture medium with 0.45% of WE; 1.6% of WE; 3.8% of WE respectively before the initiation of the experiment. It was observed that Westiellopsis could accumulate 1.26, 2.62, 3.94 ?g of mercury, Anabaena could accumulate 1.19, 2.46, 3.86 ?g of mercury, Nostoc could accumulate 0.85, 1.14, 2.28 ?g of mercury and Oscillatoria could accumulate 1.41, 2.71, 3.85 ?g of mercury from the WE inoculated culture medium with in 15th days of exposure. Maximum accumulation of mercury was noted in case Oscillatoria and minimum of residual mercury accumulation was observed in case Nostoc. In case of Westiellopsis 1.95, 8.57, 20.9 ?g of mercury was removed from the medium by way of accumulation and volatilization from the medium and in case of Anabaena 2.0, 8.7, 21.03 ?g of mercury was removed from the medium by way of accumulation and volatilization from the medium. In case of Oscillatoria 0.03, 0.08, 0.38 ?g of mercury was removed from the medium by way of accumulation and volatilization from the medium and in case of Nostoc 0.06, 0.38, 0.13 ?g of mercury was removed from the medium by way of accumulation and volatilization from the medium. The most important aspect was the non availability of mercury in the air of culture vessels in Oscillatoria and Nostoc exposure. However, significant amount of mercury was recorded in the air available inside the culture vessels of Westiellopsis and Anabaena exposed culture vessels. Interestingly, significant amount of mercury was detected in air collected and pumped from the experimental culture vessel. Both Westiellopsis and Anabaena could remove significant amount of mercury from the medium, whereas Nostoc and Oscillatoria could not remove significant amount of mercury except by way of residual mercury accumulation. The only interesting finding was that all the four algae could resist and tolerate mercury to a significant amount within a period of 15th days of exposure. No residual or floating mercury was recorded in control cultures for all the four algae tested through out the experimental periods.