Phytoremediation of Metals and Metalloids from Industrial Wastewater

Abstract

Heavy metal and metalloid pollution are growing concern around the world. Toxic heavy metals (HMs) such as cadmium (Cd), chromium (Cr), mercury (Hg), arsenic (As), lead (Pb), and zinc (Zn) are a major environmental issue which is generated from anthropogenic activities. Metals and metalloids are a class of elements that fall between metals and non-metals in respect of physico-chemical characteristics. The absorption of such toxic metals in farmlands raises concerns about food safety as well as decreases in plant growth and productivity and yield of crops. Several metalloids are recognized to be required or quasi-essential for plant growth and development, such as boron, selenium, and silicon. Various ions may be beneficial to plant growth and development when present in low concentrations, but when present in large concentrations, they frequently have harmful impacts. Understanding the molecular mechanisms involved in metalloid absorption by plant roots, subsequent transport to various tissues, and inter/intra-cellular redistribution is crucial in this regard. There have also been discoveries of different transporters and membrane channels involved in these processes. It has also touched on the absorption, distribution, and storage of metalloids in plants, as well as the molecular mechanisms that underpin their response. Traditional wastewater treatment technologies are typically expensive, time-consuming, dangerous to the environment, and inefficient. The phytoremediation of metals and metalloids have been examined in depth in this review. Furthermore, we have discussed earlier theories and arguments about the role and consequences of metalloids in plants using current information to provide interesting insights. Researchers focus on techniques that used enhance the accuracy of phytostabilization and phytoextraction, such as genetically engineered, microbiota and chelate-assisted strategies. The above overview also highlights the limitations and future perspectives of sustainable phytoremediation.