Utilization of water hyacinths for the extraction of heavy metals from contaminated water - organic acid assisted phyto remediation

Concentrated urbanization and the demand for better to best products to enhance quality of life is boosting the intense industrialization, which is ultimately posing burden on nature's resources (Rizwan et al. 2017). Open discharges of industrial effluent enriched with inorganic toxicants are merging into rivers and streams, reaching to agricultural land; its utilization for crop cultivation is now common and preferable practice by the farmers in Pakistan (Ali et al. 2015). According to Mohiuddin et al. (2010) and Adress et al. (2015), fertile lands are getting polluted with heavy metals (HMs) concentrations transported within unprocessed industrial effluent. This contamination is threatening by inclusion into the entire food web and causing damage among biota. Among HMs, several are prominently fond in industrial wastewater, i.e., chromium (Cr), cadmium (Cd), lead (Pb), zinc (Zn), silver (Ag), and copper (Cu). Phytoremediation is green, solar driven and efficient technique which can be further modified with acid amendments that act as chelating agent in HM removal and in supporting plant function (Farid et al. 2018). This study was designed to evaluate the potential of water hyacinths (Echhornia crassipes) being hyperaccumulator on the extraction of Cr (stable) and Cd (mobile) from water. These two metals are collectively discharged from metal plating industry. Application of citric acid (CA), an organic acid, was the modification of this technique to get better outcomes in terms of water treatment. Effects of Cr, Cd and CA on physiology of water hyacinths were also estimated.