Comparative study of metal uptake by Eichhornia crassipes growing in ponds from mining and nonmining areas-a field study

The study deals with metal (Cu, Mn, Pb, Cd) concentrations in sediment, water, and corresponding leaf samples of Eichhornia crassipes obtained from ponds in nonmining (P1) and mining (P2, P3, P4) regions. In spite of significant high metal concentrations in sediments from mining regions rather than from nonmining regions, the unelevated SQG-I (sediment quality guideline index) values proved low levels of toxicity. Irrespective of the wide range of metal concentration in sediments, the levels in water had been nearly consistent in all the ponds. Concentration of metals in leaves decreased with an increase in concentration in the substrate. Mn, Cu, and Cd accumulated within the range of MAC (maximum allowable concentration) for plants, whereas Pb accumulated above the limit. BAF(sl) (bioaccumulation factor with respect to sediment) values for Mn (0.20-0.27) were highest, followed by Cu (0.13-0.20) and Pb (0.03-0.20), whereas BAF(wl) (bioaccumulation factor with respect to water) was highest for Cu (428-3205), followed by Mn (285-1100), Pb (242-506), and Cd (7-130). This study concludes that E. crassipes plays a very important role in removing the metals from the pond ecosystem, whereas leaves of this plant can be used effectively for biomonitoring surveys. E. crassipes can be used for phytoremediation of polluted wetlands through proper management strategies.