Water hyacinth (eichornia crassipes) as a phytoremediation agent for heavy metal removal in acid mine drainages generated from the urban mining of e-wastes: a bibliometric review

Abstract

Generation of Acid Mine Drainage (AMD) is a problem that is associated with the urban mining of e-waste. Raised acidic conditions resulting from AMD discharge into the surrounding environments and cause toxic heavy metals (HMs) to dissolve, transport, and accumulate in the aquatic environments. Since the elevating concentrations of heavy metals due to AMD discharge exceed the threshold limits, beyond which the health of the living organisms is compromised, remediation of AMD has proven to be taken into consideration. Out of many strategies, passive treatment techniques can be mentioned as the newest approach to remediation AMD. Remediation methods for AMD can be divided into two categories, and they are active systems and passive systems. When comparing these two methods, active systems accrue more financial costs than passive treatments. More than 50 studies have focused on constructed wetland systems under passive technologies since it is self-sustaining once established, and they are cheaper than active treatment systems. The use of several aquatic plants such as water hyacinth, water lettuce, and water cabbage for the remediation process is of significance in constructed wetland systems. This study reviews the experimental findings on HM removal under several conditions using water hyacinth plants in different studies that have been done previously.