Restoration of Degraded Coastal Agroecosystems through Phytoremediation

Abstract

The potential of phytoremediation for decontamination and restoration of an acid sulphate wetland agro ecosystem was evaluated by taking Kari lands of Kuttanad, Kerala as the test site. Soil/sediment and water samples from rice fields and canals/waterways surrounding the rice fields were collected during summer season and analysed for different chemical parameters. The aquatic macrophytes from the same sites were also collected and analysed for elemental composition. Data on elemental status of soil indicated that the soil contains toxic levels of Fe, Al, S and contaminated with heavy metals like Cd, Zn, Cu and Pb. With regard to water quality, it was found that the water has been contaminated with NO₃-N, S, Fe, Mn and Al. Chemical analysis of native aquatic macrophytes revealed their ability for phytoextraction of elements from soil and their accumulation in plant parts. Bioconcentration factors were calculated for toxic elements and phytoextractors for different elements were identified. Hydrilla verticilata was the best phytoextractor for Fe, Zn, Cu and Al followed by Eichhornia crassipes. Cyperus species was a good phytoextractor for Mn and Eichhornia crassipes was the best phytoextractor for Cd and Pb.