Aquatic Macrophytes for Phytomining of Iron from Rice Based Acid Sulphate Wetland Ecosystems of Kuttanad

Abstract

Phytomining is an effective plant based technology suitable for the cleanup of aquatic ecosystems contaminated with toxic metals. Acid sulphate soils of rice based wetland ecosystems of Kuttanad faces acute problem of Fe toxicity coupled with extreme acidity. Phyoremediation potential of aquatic macrophytes viz., Hydrocotyl asiatica, Bacopa monnieri, Eichornia crassipes and Cyperus pangorei under graded doses of Fe ranging from zero to 3000 mg per kg of soil was evaluated in a pot culture experiment. On 45th day after planting the plants were harvested and analysed for elemental concentration and soil samples for different forms of Fe. The total Fe content of the soils showed a mean value of 7.05% and available Fe 346 mg kg^-1. Among the aquatic macrophytes, Eichhornia crassipes was found to be the best extractor of Fe as evidenced by its highest shoot and root dry matter production, Fe content in both shoot and root, Fe extraction efficiency, translocation index and Fe accumulation factor.