ORIGINAL ARTICLE

An appraisal on the Stress amelioration of Effluent treated Vetiver plants amended with Ascorbic acid in Constructed Wetlands

Industrial effluents are one of the major sources of direct and continuous input of pollutants in water bodies. It is the waste generated by manufacturing or industrial processes and it include wide variety of pollutants including harmful heavy metals. Therefore, water treatment is unavoidable though it is very expensive and very hard to carry out. Chemical treatments and electro-kinetics have been resulting in rendering the soil biologically dead and useless for plant growth. Therefore, vegetative methods (phytoremediation using hyper-accumulator plants) are thought to be most practical and economical. The study was conducted to find out the physiological and biochemical changes in Vetiver grass (Vetiveria zizanioides (L.) Nash.) treated with service station effluent in constructed wetlands, and to assess the phytoremediation potential of it. The study also aimed to evaluate the effect of ascorbic acid treatment on the phytoremediation potential and biochemical changes of the wastewater stressed vetiver plants. In the study, ninety days old vetiver plants grown in constructed wetlands were treated with 15 L of automobile service station effluent for 15 days. Another test group plants were treated with the effluent along with ascorbic acid (10 mg ml ^-1) on alternate days for the 15 days. After the experimental period, treated effluents and the plant parts of the control and test groups were collected, and various chemical and biochemical attributes were determined following the standard procedures. Results of the study showed that more than 50% removal of pollutants was achieved after 15 days treatment in constructed wetlands. The biochemical analysis of treated plant parts showed decrease in the concentration of pigments, biomolecules, total phenols and nutrients. Also there was increase in the concentration of antioxidants and malondialdehyde. The study also revealed that the ascorbic acid addition to the constructed wetland system increased the concentration of pigments and biomolecules in the test plants. Ascorbic acid amendment enhanced the defence mechanism against the wastewater induced oxidative stress and thereby increased the pollutant removal efficiency of vetiver.