Abstract

Water hyacinth (Eichhornia crassipes) is abundantly found in waste water and in soil (landfills) of Taxila, Pakistan. It is a well known hyper-accumulator, bioindicator and phytoremediator of nitrogen and metals. In the present study, three different experiments were performed and tried to lay down a foundation for further research in the field of environmental studies. Firstly, we assessed the metallic concentrations of Taxilian water hyacinth; secondly we isolated some selected microbes from its roots and; thirdly, these microbes were identified by biochemical tests and were purified. Our results verify the fact that besides nitrogen fixation, presence of metal binding proteins and humic acids in water hyacinth, these microbes play a key role. From the literature, we also tried to show the relationship of these microbes with absorption, adsorption, phytoextraction and phytoremoval of nitrogen and metals from waste water and contaminated soil with water hyacinth. It is also evident that water hyacinth may be used as a tool in bio mining of metals.

Key words: Water hyacinth, Aspergillus niger, Azotobactor, Thiobacillus thiooxidans, Thiobacillus ferrooxidans, environmental pollution.