International Journal of Environmental Sciences

The present investigation was aimed to assess the effect of zinc chloride on some biochemical parameters and capacity of zinc uptake by floating aquatic macrophyte Eichhornia crassipes. Initially the effects of increasing zinc concentration on the growth of E. crassipes including root length, leaf area and biomass production was studied. Zinc was accumulated in increasing order in the plants treated with increasing concentration of zinc chloride and shows maximum efficiency of accumulation of Zn⁺⁺ up to 75 ppm present in the solution. At higher zinc chloride (75 ppm) concentration chlorophyll content of E. crassipes is slightly affected whereas increase in the carotenoid, polyphenol and proline content was observed. The effect of zinc concentration on antioxidant enzyme activities such as catalase and peroxidase of E. crassipes were also investigated. Water quality analysis with reference to electrical conductivity, pH, total dissolved solids (TDS), alkalinity, hardness, sodium and potassium content were systematically investigated. COD as well as BOD content of water increased in all the sets with increase in the concentration which might be closely associated with the external addition of zinc chloride and definitely due to root exudates, degrading plant parts. The maximum values of bioconcentration factor (BCF) for Zn was 545.4, suggesting that water hyacinth was a moderate accumulator of Zn and could be used to treat fresh waters and industrial wastewater contaminated with zinc concentrations.