South Dakota Petroleum Release Sites

Application of Triad principles at five South Dakota UST "legacy" sites.

Background

In 2004, EPA TII and Argonne National Laboratory worked with a suite of stakeholders including the South Dakota Petroleum Release Compensation Fund (PRCF), multiple private sector contractors, and the South Dakota Department of Environment and Natural Resources (DENR) to apply Triad principles at five South Dakota UST "legacy" sites. The locations were considered legacy sites because petroleum releases had been discovered years ago (in one case, more than a decade ago), yet none of the sites were moving toward regulatory closure.

The effort incorporated the application of DWS and RTMS at all five sites, as agreed upon during a one-day systematic planning session. Attendees included representatives of the South Dakota (SD) DENR, SD Petroleum Release Compensation Fund, EPA contractors (Argonne and Columbia Technologies), and contractors representing the owner/operators of the five sites.

The systematic planning session included both a technology transfer component and a planning component. The technology transfer component involved an introduction to Triad principles and a course of instruction about the strengths and weaknesses of direct push and Membrane Interface Probe (MIP) technologies. Some participants favored existing regulatory approaches involving standard data collection techniques and the use of a fixed laboratory for environmental media analyses (hereafter referred to as the standard practice approach). Other participants favored an approach involving a dynamic sampling strategy and the use of a MIP for data collection without any fixed laboratory analyses (hereafter referred to as the MIP-only approach).

As a result of the systematic planning session, the "MIP only" and "standard practice" approaches were combined. It was agreed that the investigation of each legacy site would be phased. Phase 1 would involve the use of the MIP to characterize the site to the satisfaction of all stakeholders. The results of Phase 1 would then be used to aid in the selection of sample locations, and in some cases well placement, for the collection of environmental media samples for fixed lab results in Phase II.

A key element in the resolution of DENR uncertainties was the commitment of DENR staff to be present during MIP data collection. The planning component involved developing the following for each of the five sites: project summary, CSM, CSM data gaps, and stakeholder goals and objectives required to achieve project goals. Through the course of the study, 133 MIP borings were advanced, resulting in the collection of approximately 350,000 data points.

As part of the systematic planning process, participants developed an agreed-upon data package to facilitate data visualization and data communication via Web browser-based platforms. Thus, the results of the investigation at each of the five sites were communicated to all stakeholders by the morning of the day following data collection. Armed with the high-density information and a CSM that was updated daily, project stakeholders could agree on additional data collection requirements or project completion status in a single mobilization.

The Triad approach provided stakeholders with a clear understanding of goals, steps to reach the goals, and the flexibility to augment the work plans based on field analyses. In addition, a clear cost savings was realized because of the upfront project planning and the density of data collected from each boring location. All five sites were successfully characterized in a three-week period (Association of State Underground Storage Tank Cleanup Funds 2005).

Site Progress

A No Further Action determination was issued for the Former T and T Standard site in January 2007. For the Severson’s Service site, a No Further Action determination is pending upon completion of a project to complete a water main replacement. The presence of free product at the DM&E Railroad site will necessitate a period of long-term monitoring to ensure that the free product detected during the Triad investigation is stable. The necessary corrective action has been completed at the Steve’s Amoco site, and No Further Action status is anticipated in the near future. Corrective action at the fifth site, the former Huskey Gas Station in Pierre, is ongoing. The Huskey Gas Station is located in an area that is affected by contamination from multiple sources. Contamination sources on the Huskey site have been addressed with funding from South Dakota’s Leaking Underground Storage Tank (LUST) Trust Fund. Remedies have been implemented at a number of the neighboring sites. As a result, the site has not yet achieved No Further Action status, since the Huskey site is being used to monitor the progress of remedies implemented at neighboring sites. Nevertheless, a developer plans to redevelop the site for reuse starting in mid-to-late 2008 (Bakeberg 2008).