Title: Phytopurification of wastewater loaded with heavy metals using duckweed species INTRODUCTION Preserving the quality of the environment is one of the major concerns of this century. Our biosphere is degraded by the release of natural and synthetic substances that can cause deleterious effects on living organisms. Among all pollutants, heavy metals are easily transported and accumulated in the environment. Many industries such as textile and steel, galvanic and metallurgical industries release heavy metals such as cadmium, copper, chromium, nickel and lead into wastewater (Demirenzen et al., 2007). Most heavy metals are toxic or carcinogenic in nature and pose a threat to human health and the environment (Shakibaie et al., 2008; Vinodhini and Narayanan, 2009). Several conventional methods are used for the removal of heavy metals from wastewater, including chemical precipitation, ion exchange and reverse osmosis, etc. but the main drawbacks of such treatments are the production of large quantities of sludge and the processes can be ineffective or expensive. Therefore, the search for a new, simple, effective and environmentally friendly technology involving the removal of toxic heavy metals from wastewater has directed attention towards phytoremediation (Divya Singh et al., 2012). According to UNEP, phytoremediation can be defined as “the efficient use of plants to remove, detoxify or immobilize environmental contaminants in a growing matrix (soil, water or sediment) through the natural biological, chemical or physical activities and processes of plants ”. Ideal plants for phytoremediation should possess the ability to tolerate and accumulate high levels of heavy metals in harvestable parts, while producing high biomass. Many species of macrophytes are used for...... middle of paper ......sal. Phytoremediation technology has proven to be a viable option for purifying water contaminated with trace elements as it is cost-effective and has a positive impact on the environment. In the present study, the efficiency of duckweed as an alternative and cost-effective natural biological tool in general wastewater treatment and in the elimination of heavy metal concentrations present in industrial wastewater was examined under laboratory conditions. This is an alternative technology where small-scale wastewater treatment can be achieved. It has been used recently in Bangladesh for wastewater treatment and this technology has been implemented at the village level under the UNDP project. Further research is needed through pilot projects to refine the sizing of the ponds used and determine the correct innocculum of plant material to achieve a predetermined effluent quality.