Attenuation of Chromium toxicity in mine waste water using water hyacinth

Abstract

The mine waste water at South Kaliapani chromite mining area of Orissa (India) showed high levels of toxic hexavalent chromium (Cr+6). Cr+6 contaminated mine waste water poses potential threats for biotic community in the vicinity. The current field based phytoremediation study is an in situ approach for attenuation of Cr+6 from mine waste water using water hyacinth (Eichhornia crassipes) weeds by rhizofiltration method. The weeds significantly reduced (up to 54%) toxic concentrations of Cr+6 from contaminated mine waste water when passed through succeeding water hyacinth ponds. The reduction of toxic chromium level varied with the plant age and passage distance of waste water. Chromium phytoaccumulation and Bio-Concentration Factor (BCF) was maximum at growing stage of plant i.e. 75 days old plant. High BCF (10,924) and Transportation Index (32.09) for water hyacinth indicated that the weeds can be used as a tool of phytoremediation to combat the problem of in situ Cr contamination in mining areas.

Keywords

• Chromium stress
• Mine waste water
• Phytoremediation
• Water hyacinth