Gaseous emissions of mercury from an aquatic vascular plant

Abstract

RECENT studies have demonstrated the emission of mercury to the atmosphere from a variety of sources including contaminated industrial waste beds1–4. Investigations have also shown that vascular plants can take up both inorganic and organic mercury compounds through their root systems and transport them to the leaves5,6. Separate measurements of mercury emanations from the excised leaves of three vascular plant species have shown that there is a release of volatile mercury at room temperatures7. Thus, it would seem that vascular plants have the potential to take up mercury from a substrate, to transport it, and to emit it to the surrounding atmosphere through their leaves. However, no direct measurements of such emissions from living intact plants have been reported. We report here our examination of the common reed, Phragmites communis, growing along the shoreline of a mercury-contaminated lake and our finding that these plants, growing in their natural environment, actively release mercury to the atmosphere.