Technical Impracticability of Surface Water and Ground Water Remediation in a Large Wetland Complex at the Anaconda Smelter Site, Montana

This paper will describe the results of a technical impracticability analysis for remedial actions to address metals-contaminated wetlands. The Dutchman Creek area of the Anaconda Smelter site is a large wetland complex containing arsenic-contaminated soil from smelter-related fallout. Because the contaminated soil is saturated, arsenic is mobilized, resulting in 3,800 acres of contaminated ground water. The wetland complex forms the headwaters of a spring creek which is contaminated by arsenic from the discharge of ground water. Due to the value of the wetlands in its existing condition, removal of contaminated soil was not available as a remedial option and a technical impracticability (TI) analysis was conducted for both surface and ground water. The TI analysis included the development of a conceptual site model, evaluation of treatment alternatives, and a discussion of alternate remedial strategies that would be protective of human health and the environment. The analysis demonstrated that, although source control other than removal would be ineffective for ground water and surface water cleanup, a protective remedy might still be achieved through institutional controls.