Phytostabilization as a Remediation Alternative at Mining Sites

In the last 10 years, the Bureau of Land Management (BLM) has reclaimed a number of abandoned mine land (AML) sites, often by removing mine, mill, and smelter wastes and taking them to a repository. This removal process involves excavating, hauling, placing, and capping tens of thousands of cubic yards of material, which can be quite costly.

BLM is seeking more cost-effective methods for reclaiming AML sites. Phytostabilization is a promising alternative for accomplishing the goals of a removal at a tenth of the cost. Phytostabilization is an in situ technology involving soil amendments and metals-tolerant plants to establish a ground cover that can reduce migration of metals to air, surface water, and ground water; reduce soil toxicity; and meet applicable, relevant, and appropriate requirements (ARARs). This technology has been found effective under certain conditions.

Through a 3-year applications of science (AOS) grant, BLM’s National Science and Technology Center (NSTC) has worked with field offices and universities to pilot phytostabilization at two sites. This Technical Note summarizes the work done at the Keating tailings site near Butte, Montana, by Montana State University.

At the Keating tailings site, planting occurred in 2003. This year, which was the last year of the AOS grant, the test plots were in their third growing season. Canopy cover and aboveground biomass data have been collected, and samples have been analyzed for metal and arsenic concentrations. However, at least 1-2 years of additional monitoring of plant establishment and metals uptake sampling are required to verify the success of the technology and determine its feasibility for other AML sites on public lands.