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U.S. EPA REGION 5
RAMSEY COUNTY
NEW BRIGHTON

Congressional District # 04

NEW BRIGHTON/ARDEN HILLS/TCAAP (USARMY)

EPA ID# MN7213820908
Last Updated: June, 2009

Site Description

The New Brighton/Arden Hills Superfund site consists of the Twin Cities Army Ammunition Plant (TCAAP) and all other areas of the surrounding communities historically contaminated by the migration of hazardous substances or contaminants from TCAAP. Between 1941 and 1981, waste material was disposed of at 14 disposal areas or sites within TCAAP. The total area of the Superfund site, including the offsite contaminated groundwater plumes, is approximately 25 square miles.

Site Responsibility

Responsibility for the site resides with the U.S. Army, Department of Defense.  This site is being addressed through federal and state actions in accordance with the 1987 TCAAP Federal Facility Agreement.

Threats and Contaminants

The wastes disposed of at TCAAP included volatile organic compounds (VOCs), semi-VOCs, metals, polychlorinated biphenyls (PCBs), cyanide, pesticides, and explosives. The primary impact to the surrounding communities has resulted from VOC contamination of the regional groundwater resource, which is used for municipal and private water supplies. 

Cleanup Progress

In 1987, the Army, U.S. EPA, and MPCA entered into a federal facility agreement (FFA) for the investigation and remediation of the site. In accordance with the FFA, the Army initiated numerous cleanup activities under the Department of Defense (DoD) Installation Restoration Program, including:

Additional action was taken and included the construction of a GAC treatment system for the village of St. Anthony by U.S. EPA and MPCA. The system was completed in 1991, pursuant to a September 1986 Record of Decision.

In recognition of the need to expedite the remediation of regional groundwater contamination, U.S. EPA, MPCA, and the Army agreed to address the final remedy for the site in three stages or operable units. Operable Unit 1 (OU1) addresses the North Plume of contaminated groundwater which has migrated off-TCAAP; Operable Unit 3 (OU-3) addresses the smaller, South Plume.

Records of decision, in which remedies for these operable units were selected, were signed in 1992 and 1993. The remedies, selected, include:

The OU1 and OU3 RODs provide for containment pump-and-treat systems comprised of wells which serve the dual purposes of containment and municipal water supply for the city of New Brighton. Construction and full operation of the OU3 system began in 1994. Construction of the OU11 system was completed in the second quarter, FY1999.

For a number of years, VOC levels in monitoring wells for the South Plume have been consistently non-detectable. In 2001, U.S. EPA and MPCA approved the Army's request to temporarily cease pumping of the OU-3 extraction well-and-treatment system for remediation purposes and maintain it in "standby mode" with continued groundwater monitoring.  After a minimum of five years of non-detect VOC concentrations, the Armyr requested that the the OU3 ROD requirement for operating the South Plume extraction well be terminated.  After reviewing all relevant groundwater monitoring data, USEPA and MPCA concurred with the Army's request and in June 2006 signed the OU1 ROD Amendment.  The OU1 ROD Amendment removes groundwater extraction and associated remedy components and retains the alternate water supply, groundwater monitoring and institutional control components of the original remedy.

The last component of the final remedy for the site, a ROD for Operable Unit 2 (OU2), was signed in December 1997. The remedies selected in this ROD address contaminated soil and groundwater within the TCAAP boundary. Major elements of these remedies include:

An extensive long-term monitoring program for groundwater, surface water, and sediments is currently in place and will continue well into the future.

By summer 1999, major components of the soils remediation component of the OU2 remedy had been designed and implemented. These components included:

By summer 2002, the following on-TCAAP remedial and removal actions had been completed:

In 1996, the Army performed limited soil sampling at the 135 and 535 Primer Tracer Areas (PTAs). The PTAs were part of an Army mobilization mission at the time that the TCAAP preliminary assessment was performed and were, therefore, not investigated at the time. Additional work performed at these areas to evaluate their contamination status has included preliminary assessments in 2001, site inspections (SI) in 2002 and 2003, an Engineering Evaluation/Cost Analysis for the 535 PTA in 2009.  A removal action to address residual PAH soil contamination at the 535 PTA is expected to be completed by 2010.  The second five-year review for the New Brighton/Arden Hills/TCAAP Site was completed in September 2004.  The 135 PTA is located within the 585-acre property transfer parcel which is in the process of being transferred to the City of Arden Hills.  Any additional remediation deemed necessary within this parcel will be performed by the City and its developer, as part of the property transfer agreement with the Army and will be overseen by the MPCA Voluntary Cleanup Program.  In evaluating the adequacy of any future cleanup on the transfer property, EPA will have final concurrence responsibility.

Ongoing activities being performed on-TCAAP include: 1) operation and maintenance of on-TCAAP groundwater remediation systems (Site A and TGRS), 2) annual performance monitoring of the groundwater remediation systems, and 3) annual private well inventory.

Currently (as of early 2009) the following activities have been completed or are underway:

 1) reconfiguration/optimization of the TGRS;

2) Operable Unit 1 ROD Amendment - A ROD Amendment for OU1 was signed in June 2006.  The purpose of this amendment is to improve the method by which success in the cleanup of the North Plume of off-TCAAP contamination is measures;

3) Operable Unit 2 ROD Amendments - The OU2 ROD is in the process of being amended to address needed changes to the remedies for various portions of the OU2 remedy(e.g., at Sites I, K, 129-15, and conditions at Site C);  The amendment process is proceeding in several stages.  OU2 ROD Amendment 1, addressing changes in the soils remedy at Site C-2, was signed in July 2007.  Amendments Nos. 2 (Site I Groundwater) and 3 (OU2 Soils and Dumps) will be signed in Spring 2009, as will Explanations of Significant Difference (ESDs) for  Groundwater (ESD 1) and Soil (ESD 2) remedy changes which are not significant enough to warrant amending the ROD;

4) Aquatic Sites Feasibility Study (FS) - An FS to address the findings of the Tier II Ecological Risk Assessment is currently (2009)  under regulatory review.  The FS evaluates potential responses to the ecological risks posed by contaminants attributable to TCAAP operations to onsite and adjacent aquatic ecosystems, especially as they relates to Round Lake, a nearby lake which is part of the Minnesota Valley National Wildlife Refuge.  The draft FS is currently (2009)  under review by the stakeholders (USEPA, MPCA, USFWS, TCAAP RAB).

5) Operable Unit 3 ROD Amendment - A ROD Amendment for OU3 was signed in August 2006.  The purpose of this amendment is to eliminate the requirement for the OU3 extraction well, also known as the Plume Groundwater Recovery System (PGRS), as part of the OU3 remedy because its purpose, to prevent the spread of the OU3 plume at its leading edge, has been served.  The PGRS has been extracting clean water (i.e., non-detect for volatile organic carbon (VOC) contaminants) for at least five years.  The OU3 plume has receded significantly toward TCAAP, and it is expected to continue to recede.

7) Building 102 Groundwater Plume - During performance of an Environmental Site Assessment (ESA) by the developer of the property transfer parcel of TCAAP, the developer's contractor discovered VOC contamination around Building 102.  Subsequent investigation by the Army of the Building 102 area, documented in the Groundwater Investigation Report for Building 102 (January 2006) delineated a plume of shallow VOC-contaminated groundwater originating underneath the building.  An EE/CA for the site was completed in July 2008.  the EE/CA recommended monitored natural attenuation as a non-time-critical removal action for the contaminated groundwater.  A removal action work plan is currently (2009) under review by the regulators with implementation of the action expected in 2009.

6) Long-Term Operation and Maintenance Activities - These activities will continue to be monitored through the Annual Performance Report, which the Army will continue to generate for regulatory review until the cleanup at the Site is complete.

Based upon the completion of the ROD Amendments and associated remedial work, as well as any additional work related to the Aquatic FS, and removal actions for the 535 Primer/Tracer Area and Building 102, construction completion for the site is expected in fiscal year 2010.

Success Story

The South Plume (Operable Unit 3 [OU3]) has receded to the point where the Plume Groundwater Recovery System (PGRS) extraction well is no longer needed for remediation purposes.  The well has been shut down and the shutdown made permanent through the recent Operable Unit 3  ROD Amendment.

The New Brighton Contaminated Groundwater Remediation System (NBCGRS), the remedy for the large North Plume of contaminated groundwater desginated OU1,  continues to operate as an effective gradient control system.  Groundwater monitoring indicates that, generally, the contaminant plume continues to decrease in both concentration and size.

Community Involvement

The communities surrounding TCAAP have been, and continue to be, active in both the CERCLA cleaup and the property transfer issues at the Site.  A restoration advisory board (RAB) formed pursuant to Department of Defense guidance, composed of citizens from the local communities and charged with providing public input into the Army's cleanup of the Superfund Site, has been active since its inception in 1996.

The City of New Brighton has been an integral partner with the Army in the successful implementation and operation of the OU1 and OU3 groundwater extraction and cleanup remedies because it is the City's municipal wells which are serving, or have served, as the extraction wells for these remedies.

Finally, the Village of Arden Hills is closely involved in the proposed redevelopment of the 585 acres of TCAAP property since that redeveloped property will be incorporated into the village.

Congressional Interest

The Minnesota Congressional delegation continues to follow the progress of cleanup and property transfer at the Site.  In the mid-1990's then Congressman Bruce Vento led a public dialogue which resulted in a redevelopment plan for TCAAP ("the Vento Plan").  The Vento Plan has provided the framework for subsequent redevelopment efforts. 

 

Property Reuse

Of the approximately 2400 acres of TCAAP, control over 1500 acres has been transferred to the U.S. Army Reserve and the Minnesota National Guard.  Smaller portions have been transferred to Ramsey County for a public works facility and a wildlife corridor, and the City of Arden Hills for a new City Hall.  Approximately 660 acres was authorized by the United States Congress to be excessed and is currently in the process of being transferred for redevelopment purposes.

As of early 2009, the Army continues to negotiate with the City of Arden Hills for the transfer of 585 acres for development.

Contacts

Remedial Project Manager, U.S. EPA
thomas barounis (barounis.thomas@epa.gov)
(312) 353-5577

Community Involvement Coordinator, U.S. EPA
Don De Blasio
(312) 886-9749

Aliases

NEW BRIGHTON / ARDEN HILLS
TWIN CITIES ARMY AMMUNITION PLANT
US ARMY TWIN CITIES AMMO PLT

 

Site Profile Information

This profile provides you with information on EPA's cleanup progress at this Superfund site.

 

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