Phytoremediation of multiply metal-contaminated environments: synergistic and competitive effects between heavy metals during uptake and transport

Phytoremediation is a promising alternative to conventional metal treatment methods; however, most phytoremediation studies separately consider the removal of each individual metal, which may not fully reflect the situation present in real world contamination sites. Metal-contaminated environments seldom contain a single species of metal, and are instead host to several types of toxic metals and other contaminants. Consequently, the synergistic and antagonistic effects displayed between essential and non-essential metals, as well as these between metallic and non-metallic contaminants, are an important factor in determining the bioremediative efficiencies of plant species. The present chapter outlines the uptake, transport and sequestration mechanisms relevant to heavy metal accumulation, considers the potential competitive and cooperative interactions that occur between metals during these processes, details the current literature regarding bioremediation in multiply metal-contaminated environments and offers insights into the biochemical interactions underlying the trends observed for the beneficial and detrimental effects displayed between the accumulations of certain metals. We also illustrate the potential of metal remediation by aquatic macrophytes, a group known for the effective remediation of multiple metals, which possess life histories that render them particularly conductive to studies investigating the impact of multiple metals on metal uptake. © 2014 by Nova Science Publishers, Inc. All rights reserved.