Superfund Research Program
Phytostabilization and Retirement of Mercury from Wet Ecosystems
Project Leader: Mark P. Elless
Grant Number: R43ES017572
Funding Period: Phase I: August 2010 – January 2012
Because environmental mercury poses significant challenges to global public health, reducing mercury (Hg) levels in air, soil, and water is an international priority. Widespread distribution of mercury makes current methods of remediating Hg contamination, such as excavation and replacement of soil, too expensive to be practical.
In this Phase I SBIR project, Edenspace Systems Corporation is collaborating with the Energy and Environmental Research Center (EERC) to develop an innovative, low-cost method of extracting Hg from wet ecosystems. Rabbit-foot grass, a recently-identified Hg-hyperaccumulating plant species, readily binds with reduced sulfur to form highly stable mercury sulfide (HgS). This effectively retires the mercury from the global cycle.
This process utilizes sulfur (S), a nutritionally essential trace element that is naturally accumulated by plants from soils, to render the accumulated mercury biologically inactive. Because the accumulated mercury is trapped in an insoluble, non-bioavailable form, the mercury stored in the plant may then be allowed to remain on-site. This eliminates the need for harvest and disposal and reduces the burden on hazardous waste landfills. The Phase I research includes: demonstration of simultaneous hyperaccumulation of Hg and S in rabbit-foot grass; demonstration of the formation of HgS; and correlation of HgS formation to Hg accumulation.
The end result of the project will be to establish the foundation for a low-cost, solar powered method of removing and stabilizing mercury over large areas of soil and large volumes of water. Exposure to mercury contributes to significant human health problems, and this project demonstrates a new, cost-effective remedial strategy for the complete removal of mercury from the global ecosystem.