RESUMO
The waste water showed high values of total solid (TS), hardness and chloride with slightly alkaline pH along with high concentrations of Cr (2.03 mg l-1), Ni (1.59 mg l-1) and Zn (0.46 mg l-1). The concentration of Cu (0.21 mg l-1) and Zn in industrial waste water was low than Ni and Cr. The diluted (25 and 50%), undiluted (100%) waste water was used to irrigate the lettuce plants grown in alluvial soils. Plants accumulated heavy metals in their shoot (Ni, 13.65; Cr, 19.73; Zn, 21.6 and Cu 14.76 1g g-1 dry weight) and root (Ni, 41.4; Cr, 31.6; Zn, 30.2 and Cu 15.85 1g g-1 dry weight) in high concentrations after irrigation with undiluted industrial waste water. Maximum accumulation of heavy metals was found in the root than the shoot (13.65-21.60 1g g-1 dry weight). Dry matter yield and biomolecules (Chlorophyll a, b and sugar contents) was found to increase with increase in concentration of waste water upto 50 %, which declined at the exposure of undiluted waste water. Catalase activity was found to increase with increase in waste water concentrations upto 100%, while carotenoids content increased in plants only upto the 50% waste water irrigation. Use of industrial waste water, in such form, on agricultural lands is not found suitable without proper treatment. It could be injurious to plants growth and may be a potential threat to food web.