Research Product

Aquatic macrophytes typically are classified as submerged, floating, or emergent plant species and are widely distributed in various aquatic environments, from fresh- to saltwater as well as the littoral through pelagic zones. They have several characteristics favorable for metal accumulation. First, in terms of biomass, aquatic and wetland macrophytes are the predominant organisms in the highly productive, littoral ecosystems, such as wetlands and seabeds (Brix and Schierup 1989). Second, leaves and epiphytes provide an expanded area to trap particulate matter, sorb metal ions, and accumulate and sequester pollutants (Ward 1987; Bishop and DeWaters 1988; Levine et al. 1990). Third, rooted species can absorb metals through their roots and rhizomes as well as through their leaves (Welsh and Denny 1980; Heisey and Damman 1982). Fourth, most aquatic macrophytes are stationary and thus are useful as sentinel species for various contaminants such as metals (Say et al. 1981). In this chapter, the discussion will focus primarily on the ability of vascular plants and mosses, both fresh- and saltwater species, to accumulate toxic, heavy metals or metalloids. Macroalgae, microalgae, and other species will be mentioned for comparison only. This chapter serves as an overview of studies on the topic since 1980 and provides basic, synthesized information. A few major works prior to 1980 also are cited. Many earlier and other uncited publications are included in the 'Additional Literature' section at the end of this chapter.