Phytofiltration of cadmium from water by Limnocharis flava (L.) Buchenau grown in free-floating culture system

A hydroponics experiment was conducted to examine the phytofiltration of Cd by Limnocharis flava (L.) Buchenau grown in low-level Cd-contaminated water. For this, 45 d old seedlings of L. flava were transferred to a floating-support culture system containing nutrient solution spiked with four levels of Cd (0.5, 1, 2 and 4 mg l(-1)) and were separately harvested after 3, 7, 21 and 30 d. After 30 d harvesting, the percentage removal of Cd from the above four treatments reached up to 98, 96, 95 and 93%, respectively. Interestingly, all treatments had higher growth rate than control at 95% confidence level and plants still remained healthy at 4 mg l(-1) Cd exposure. The bioaccumulation study showed a linear relationship of Cd (R-2 = 0.896-0.999) in all plant parts with the exposure time (3-30 d) and Cd concentrations in hydroponics system (0.5-4 mg l(-1)). Although, the root of L. flava had higher Cd concentration than leaf and peduncles, the total Cd concentrations in aerial plant parts were higher than the roots. The maximum bioconcentration factor (BCF) and translocation factor (TF) value of L. flava were calculated as 984.42 and 1.43, respectively. Estimated Cd accumulation capacity of L. flava per unit area (m(2)) was found to be in the range of 218. 35-1698.92 mg m(-2). The experimental results demonstrated that L. flava is a suitable candidate for the phytofiltartion (>93%) of Cd from low-level Cd-contaminated water. (C) 2009 Elsevier B.V. All rights reserved.