Paper mill effluent induced toxicity in Eichhornia crassipes and Spirodelapolyrrhiza.

Paper mill effluents were collected and analysed for physicochemical charac teristics. The tocicity of effluents on chlorophyll-a content and biomass o f Eichhornia crassipes Mart Solms and Spirodela polyrrhiza (L.) Schleiden w ere determined by exposing these to different concentrations of paper mill effluents at different intervals. Chlorophyll-a content and biomass of both the macrophytes decreased when exposed to the paper mill effluent. Extent of reduction was in proportion to the concentration of effluent and duratio n of exposure. The metal (Cu, Fe, Zn and Mn) content of effluent decreased with exposure to these macrophytes for 168h. Reduction in metal contents of the effluent is probably due to uptake of these metals by the aquatic macr ophytes.