ECO-TOXICITY AND TEMPERATURE STRESS STUDIES OF HEAVY METAL CONTAINED PULP AND PAPER MILL INDUSTRIAL EFFLUENT ON CYANOBACTERIA UNDER LABORATORY CONTROLLED CONDITIONS .Tripathy, A.P., Padhi, N.1, Dixit, P.K. and Panigrahi, A.KAbstract An attempt is made to study the toxicity of the discharged Paper and Pulp industrial effluent and impact of temperature stress on two microalgae. The industrial effluent is deadly toxic and contained heavy metal like cadmium, mercury and lead at higher concentrations. The values were much more than the stipulated limit prescribed by PCBs. The year wise comparison of effluent analysis data indicated that the industry is not treating the effluents biologically to eliminate the heavy metals present in the effluent but discharges the effluent straight in to the river. The toxicity study indicated that mercuric nitrate, cadmium chloride and lead nitrate individually is toxic to microalgae at lethal concentrations. The study also indicated that these toxic heavy metals when mixed become deadly toxic and the LC values decreased significantly. The effluent containing all the three heavy metals was less toxic when compared to individual chemicals or chemicals in combination probably due to the presence of other chemicals in the effluent which might have decreased the toxicity of the effluent. Out of the two alga tested Westiellopsis prolifica is more tolerant than Anabaena cylindrica. Both the alga showed similar behaviour towards different toxicant chemicals tested in the present study. Both Westiellopsis prolifica and Anabaena cylindrica are nitrogen fixers and farmer friendly, their tolerance towards heavy metal toxicants and heavy metal contained toxicant like effluent of the Paper mill effluent bears significance. These two algae showed potency and can be used as potential detoxifiers of the heavy metal contaminated sites. |