The present study deals with the characterization of effluent released from Brahmaputra valley Fertilizer complex, Namrup, Assam, India and distribution of heavy metals in water near to effluent discharge channel. The extent of damage caused by the effluents on physiological and biochemical properties of plants was investigated. Chlorophyll pigment, foliar protein and sugar concentration were measured in Amaranthus spinosusL., Cassia obtusifolia L. Croton bonplandianum Baill. Leonurus sibiricus L. during the growing season and compared with control. Results indicated that effluents contained toxic elements and the observed weeds were found to be susceptible while C.bonplandianum shows tolerance to some extent. Present study suggests that although weeds are often tolerant to extreme hostile environment but some time contaminated soil threatens their normal metabolisms. This leads to some new dimensions towards further research.

Key words:  Chlorophyll, effluent, heavy metal, protein, sugar, weed.