Pergamon Chemosphere, Vol. 39, No. 12, pp. 2159-2169, 1999 0 1999 Elwier Science Ltd. All rights resewed PII: SOO45-6535(99)00095-8 0045-6535/99/S - see front matter BlOACCUMUl..ATlON OF CHROMIUM AND TOXICITY TO PHOTOSYNTHETIC PIGMENTS, NITRATE REDUCTASE ACTIVITY AND PROTEIN CONTENT OF NELUMBO NUCIFERA GAERTN.* Poornima Vajpayee, S. C. Sharma, R. Cl. Tripathi **, U. N. Rai and M. Yunus’ Environmental Sciences Division, National Botanical Research Institute, Lucknow 226 001, India. School of Environmental Sciences, Babasaheb Bhimrao Ambedkar University, Lucknow 226025, India (Received in Japan I I March 1998; accepted 8 March 1999) ABSTRACT A study was conducted to assess the abilty of N. nucifera Gaertn. in chromium removal and in bioassay using a few modifiable physiological responses. Plants grown in different chromium concentrations (50 to 200 PM) showed appreciable amounts of the same accumulated in their tissues, maximum being in roots. Higher amounts of chromium accumulated in plant tissues result significant inhibition in chlorophyll, protein contents and in vitro nitrate reductase activity in test plant, A concentration - duration dependent response induced by chromium was also recorded. Sensitivity of nitrate reductase activity in the presence of both nitrate and ammonical nitrogen could be used as a bioassay index for toxicity assessment concentrations of chromium. 81999 Elsevier Science Ltd. All rights reserved against supraoptimal INTRODUCTION Chromium is one of the most toxic metal widely found in water bodies. The large scale use of chromium in metallurgical, pigment and dye, textiles and electroplating make these industries potential source of chromium pollution. According to a recent estimate ca. 2000-3200 tonnes of chromium escape into the Indian environment annually from the tanning industries alone [I]. Chromium level in the effluents usually range between 2000 - 5000 pg ml -’against the recommended permissible limit of 2.0 pg ml -I. Contamination of water resources by the effluent is posing threat to aquatic ecosystem. Chromium interferes with several metabolic processes of plants and animals [2, 31. Chromium (VI ) is highly toxic to plants which results in reduced roots, phytomass and photosynthetic pigments; chlorosis; stunting and plant death eventually [4,5,6,?]. Aquatic plants have shown greater potential in ameliorating the metal load of waste water * NBRI Research Publication No. (ns) ** Corresponding Author (Fax-91 -0522-282881); email : tarunaro@lwl .vsnl.net.in 2159