Recent Advances in Phytoremediation of Toxic Metals from Contaminated Sites: A Road Map to a Safer Environment

Abstract

Toxic contaminants, or metal and metal-containing compounds, that are released into the environment from various anthropogenic sources cause severe environmental problems by destroying soil fertility, causing scarcity of resources as well as affecting human health. Thus, remediating environmental pollution, especially heavy metal contamination, is necessary in overcoming negative impacts on ecosystem health. Heavy metal (HM) contaminants threaten both human and environmental health. One report states there are more than 1.7 million metal- contaminated sites in central and eastern European countries that require appropriate reclamation. It was also observed that severe soil and water pollution in developing countries such as China, Pakistan, India, and Bangladesh results from small indus- trial effluent outputs over and near agricultural areas. Phytoremediation, although it is not new, is an efficient method to clean up toxic contaminants by employing different plant species. Although this technology is successful at the laboratory level, reports underlining the unsuccessful and inconclusive attempts in its use at the field level encouraged us to critically access why it is not satisfactory in the field, and also to find evidence that it is a promising remedial strategy without emphasizing negative perceptions. Analyzing the previous reports suggests two main themes for our attention. (1) Plant stress factors pose challenges in field application, although such were negligible with laboratory and greenhouse acclimatization. (2) Methods of phytoremediation should be assessed because often the decrease in contaminants is not adequate to demonstrate the occurrence of active remediation. Keeping these points in mind, this chapter focuses on the challenges in remediation, emphasizing rhizoremediation with detailed approaches in advanced technologies to confer environmental safety and assure human health. M.