Supporting Tribal Revitalization Efforts

A Quick Look
EPA provides technical assistance and other support to states and tribes that are interested in implementing more effective approaches to attaining productive reuse of sites.
The use of a CSM enabled the Tohono O’odham Nation to establish a course for its project that is resource-effective, technically sound, and defensible.
Careful planning and the use of creative field-based technologies helped EPA Region 8 and the Crow Creek Sioux Nation to produce a higher density of data and affordably manage uncertainty.

State and tribal response programs oversee assessment and cleanup activities at most of the brownfields sites across the country. EPA provides technical assistance and other support to states and tribes in order to help them implement more effective approaches to attaining productive reuse of sites. Two examples of tribal revitalization efforts in partnership with EPA that are based on the use of the Triad approach involve the Tohono O’odham Nation in Arizona and the Crow Creek Sioux Nation in South Dakota.

In October 2002, the Tohono O’odham Nation requested that EPA’s BTSC provide support for planning an environmental investigation for the former Minerec Mining Chemical facility. The Minerec facility was constructed in 1990 on native desert in the San Xavier Business Park on land leased from the Tohono O’odham Nation. In 1991, Minerec began limited production of sulfur-containing chemicals that are used in the mining industry to separate ore and a pesticide for agricultural use. Although known locations of chemical releases to facility soil have been investigated, studies have concluded that further investigation is needed. Investigations would be conducted to address uncertainties regarding undocumented, undiscovered releases that may have impacted the facility and to further define areas of known releases to support site cleanup planning.

Systematic planning involved developing a CSM to incorporate existing information and to help design and direct data collection activities supporting reuse plans. The three main tasks identified by BTSC for the investigation included:

• Conducting a soil gas survey using direct-push drilling methodology for sample collection and an on-site laboratory for analysis
• Collecting and analyzing subsurface soil samples to a depth of 20 feet using direct-push drilling methodology and an on-site laboratory
• Further assessing vertical migration of contamination and potential groundwater impacts (if the joint two tasks indicated a potential threat to groundwater).

The soil gas and soil boring investigations were to be conducted in a single mobilization.

The use of a CSM enabled the Tohono O’odham Nation to establish a course for the project that is resource-effective, technically sound, and defensible. The systematic planning process made use of a decision tree and real-time uncertainty management practices to reach critical decision points in a single mobilization.

At the Ft. Thompson landfill, the Crow Creek Sioux Nation worked with EPA Region 8 to apply the Triad approach in order to develop a model for landfill closure. Tribal concerns about the landfill site involved impacts on residences and recreational areas, surface water impacts, the ability to reuse land for grazing and other habitat purposes, and official site closure.

The Ft. Thompson landfill, a 12.5-acre community dump used from the 1960s through 2000 for waste burning and disposal, was used primarily by homeowners and small businesses. The potential existed for disposal of pesticides, petroleum products, batteries, and metals. A soil cover had been placed over the dump; some pits and burn areas remained visible.

BTSC assisted EPA Region 8 in formulating an initial CSM that:

• Focused data needs on surface soil and surface water (runoff) pathways instead of the landfill
• Improved data density through use of field-based methods and a dynamic work strategy
• Helped Region 8 develop a model for landfill investigations

Based on BTSC recommendations, the project team:

• Eliminated the need to drill into and beneath the landfill (potentially creating new pathways)
• Selected field-based methods to characterize soil and sediment for metals (X-ray fluorescence), total petroleum hydrocarbons (TPH) (colorimetric test kits), and chlordane and other chlorinated pesticides (immunoassay test kits)

Careful planning helped to ensure that the data collected would meet the intended use. Creative field-based technologies were used to affordably manage uncertainty, producing a higher density of data and more defensible decisions. The end result is that decisions made about the site were supported by better information, thus providing a model for future investigations of this type.

The two examples summarized above demonstrate the benefits of improved decision-making through systematic planning. For more information, visit www.brownfieldstsc.org.

For more information see the following resources:

(Chris to add a function here)

Sunday, September 7, 2008