Toxicological evaluation of bacterial decolourised anaerobically treated distillery effluent with common duckweed (Lemna minor)
Chandra, R.; Srivastava, A.
Journal of Environmental Biology 25(1): 93-98
2004
ISSN/ISBN: 0254-8704 PMID: 15303710 Document Number: 569534
Duckweed (L. minor), a small vascular plant that grows rapidly, is sensitive to a wide variety of toxicants and is easy to culture. A method for the measurement of duckweed frond growth, and chlorophyll, protein and biomass contents as indicators of growth inhibition is described. The physicochemical analysis of anaerobically treated distillery effluent revealed high BOD (52 400 mg/litre) and dark brown colour (180 000 Co. Pt.). This effluent showed high toxicity to L. minor after 96 h of exposure under laboratory conditions. The EC50 value of the fronds for chlorophyll, protein and biomass was 2.5%; however, the bacterial decolourized effluent showed reduction of BOD (87.50%), COD (84.50%) and colour (76%). Toxicity evaluation with L. minor showed toxicity reduction of up to 63% for all the evaluated parameters. The EC50 noted for chlorophyll, protein and biomass was 100% concentration of decolourized effluent.