WESTLAKE LANDFILL
BRIDGETON, MO
Cleanup Activities
Sign up for this Superfund site’s mailing list
On this page:
On related pages:
Background
The 200-acre West Lake Landfill site is located at 13570 St. Charles Rock Road in the Earth City Industrial Park in Bridgeton, Missouri. It is surrounded by commercial/industrial and agricultural land on the eastern edge of the Missouri River floodplain. From 1939 to 1985, limestone was quarried on site. Beginning in the 1950’s, parts of the site property were used for landfilling of municipal solid waste and construction debris. Some areas of the site became radiologically contaminated in 1973 when soils mixed with uranium ore processing residues were brought to the landfill and presumably used as daily cover in the landfilling operation. An adjacent property has also been impacted, presumably by erosional migration of radiologically contaminated material from the landfill. This property, known as the “Buffer Zone,” was subsequently purchased by the landfill operator. It is considered part of the site and is enclosed within the site's perimeter security fence. Another small piece of privately-owned commercial property, referred to as “Lot 2A2 of the Crossroads Industrial Park,” (Lot 2A2), is located immediately north-northeast of the Buffer Zone. This area is also impacted by radiologically contaminated soils that eroded and migrated from the Area 2 landfill berm. All together, the radiologically contaminated areas of the site, identified as Area 1, Area 2, the Buffer Zone and Lot 2A2, have been designated as Operable Unit 1 (OU-1) of the West Lake Landfill Site.
Also located on the site is the Bridgeton Landfill, the Inactive Sanitary Landfill, and the Closed Demolition Landfill. The 1977 gamma flyover data suggested radiologically impacted soils were not placed in these landfills; however additional data is needed to investigate these areas for the final remedy. The Bridgeton Landfill did not receive radiologically contaminated soil and ceased accepting wastes in 2005. These areas of the site have been designated as Operable Unit 2 (OU-2). Oversight of activities at the Bridgeton Landfill and the Closed Demolition Landfill have been deferred to the Missouri Department of Natural Resources. The EPA is overseeing remedial design activities at the Inactive Sanitary Landfill in OU-2.
A third Operable Unit (OU-3) has been designated to investigate groundwater beneath the entire West Lake Landfill site.
The potentially responsible parties that have been identified for Operable Units 1 and 3 for the West Lake Landfill site are Bridgeton Landfill, LLC; Cotter Corporation (N.S.L.); and the U.S. Department of Energy. Bridgeton Landfill, LLC is the owner and/or operator of the site. Cotter Corporation (N.S.L.) and the U.S. Department of Energy arranged for disposal or treatment or arranged with a transporter for transport for disposal or treatment of hazardous substances at the site. Bridgeton Landfill, LLC is the potentially responsible party identified for Operable Unit 2 and is the owner and operator of the site.
What Has Been Done to Clean Up the Site?
Operable Unit 1:
Following completion of a Remedial Investigation and Feasibility Study, the EPA proposed a remedy for Operable Unit 1 (OU-1) in a Proposed Plan dated June 12, 2006. After an extended public comment period, the EPA selected a remedy in a Record of Decision (ROD) dated May 29, 2008. The major components of the selected remedy in the 2008 ROD for OU-1 were:
- Installation of a landfill cover;
- Consolidation of radiologically contaminated surface soil from the Buffer Zone/Crossroad Property to the containment area;
- Groundwater monitoring, surface water control and gas monitoring and control;
- Institutional controls to prevent land and resource uses that are inconsistent with a closed sanitary landfill site containing long-lived radionuclides; and
- Long-term surveillance and maintenance of the remedy.
As a result of stakeholder and community concerns following the 2008 ROD, the EPA determined that further evaluation of remedial alternatives was warranted and required the potentially responsible parties (PRPs) to conduct additional investigations and feasibility studies and update the baseline risk assessment. The Final Remedial Investigation Addendum was submitted by the PRPs on January 25, 2018 and approved by the EPA on February 2, 2018. The Final Feasibility Study was submitted on January 26, 2018, and approved with modifications by the EPA on February 5, 2018. On February 6, 2018, the EPA published a Proposed Plan for an amended remedy for OU-1 of the West Lake Landfill site and opened a 45-day public comment period. A public meeting to receive oral and written comments was held on March 6, 2018, and the Proposed Plan public comment period ended April 23, 2018, after a 30-day extension was granted. After taking all significant comments into consideration, the EPA developed a Record of Decision Amendment (RODA) that was signed by the EPA Administrator on September 27, 2018.
The selected remedy in this RODA is a modification of the alternative presented in the February 2018 Proposed Plan and includes:
- Excavation of radiologically impacted material, or RIM, greater than a level of 52.9 picoCuries per gram (pCi/g) down to a general depth of 12 feet below the 2005 topographic surface;
- Optimization of RIM removal above and below the 12-foot target depth, with excavation occurring as deep as 20 feet in some locations or as shallow as 8 feet, in order to limit potential short-term impacts to workers and nearby residents;
- Excavation of radiologically impacted soil from the Buffer Zone and Lot 2A2 of the Crossroads Industrial Park sufficient to reduce concentrations of radionuclides to background levels, in order to allow for unlimited future use;
- Transportation and disposal of excavated radionuclides at levels greater than 52.9 pCi/g at an off-site permitted disposal facility;
- Regrading of the remaining solid waste materials within OU-1; and
- Installation of a landfill cover over Areas 1 and 2 that meets Uranium Mill Tailings Radiation Control Act performance and longevity standards, Resource Conservation and Recovery Act hazardous waste design criteria, and municipal waste landfill regulations.
On May 6, 2019, the EPA entered into an agreement with Bridgeton Landfill, LLC; Cotter Corporation (N.S.L.); and the U.S. Department of Energy to conduct the remedial design of the remedy that was selected in the September 2018 Record of Decision Amendment.
Operable Unit 2:
Following completion of a Remedial Investigation and Feasibility Study, the EPA proposed a remedy for Operable Unit 2 in a Proposed Plan dated June 2006. The EPA selected a remedy in a Record of Decision (ROD) dated July 25, 2008. The major components of the selected remedy for the OU-2 Inactive Sanitary Landfill include:
- Installation of a landfill cover that meets the Missouri closure and post-closure care requirements for sanitary landfills;
- Application of groundwater monitoring and protection standards consistent with requirements for sanitary landfills;
- Surface water runoff control and gas monitoring and control consistent with sanitary landfill requirements, as necessary;
- Institutional controls to prevent land uses that are inconsistent with a closed sanitary landfill site; and
- Long-term surveillance and maintenance of the remedy.
On October 15, 2008, the EPA entered into an agreement with Bridgeton Landfill, LLC; to conduct the remedial design of the remedy that was selected in the OU-2 Record of Decision. However, the remedy design phase for OU-2 was put on hold while the Amended Record of Decision for OU-1 was finalized. Thus, in early 2019 the EPA engaged Bridgeton Landfill, LLC to restart the remedial design process for the OU-2 remedy at the Inactive Sanitary Landfill.
Operable Unit 3:
On February 6, 2019, the EPA entered into an agreement with Bridgeton Landfill, LLC; Cotter Corporation (N.S.L.); and the U.S. Department of Energy to conduct a Remedial Investigation (RI) and Feasibility Study (FS) on site-wide groundwater (OU-3) at the West Lake Landfill site. The purpose of the RI is to define the nature and extent of hazardous substance, pollutant, and contaminant impacts to groundwater resulting from Site activities and what, if any https://semspub.epa.gov/src/document/07/30487232 risks the contamination poses to human health and the environment. If it is determined that there are unacceptable levels of risk due to groundwater contamination, potential remedies to address the contamination will be developed and evaluated in the FS.
What Is the Current Site Status?
Operable Unit 1:
In September 2018, the EPA announced the amended remedy decision for the West Lake Landfill Operable Unit 1 (OU-1). The Amended Remedy includes partial excavation with off-site disposal and an engineered cover placed over the landfill when excavation is complete. The first step toward implementing the remedy is to begin the Remedial Design phase of the Superfund process. The EPA has entered into an agreement with the Potentially Responsible Parties (PRPs) for the West Lake Landfill Superfund Site to conduct the design necessary to implement the remedy set forth in the Record of Decision Amendment announced in 2018. With this agreement in place, the Remedial Design phase is now underway. To reach this agreement, the EPA negotiated an amendment to the existing Remedial Investigation/Feasibility Study Administrative Settlement Agreement and Order on Consent (ASAOC) with Bridgeton Landfill, LLC; Cotter Corporation (N.S.L.); and the U.S. Department of Energy (DOE) for the performance of the Remedial Design, subject to EPA oversight. Click here to view: ASAOC RD Amendment.
The Amended Remedy calls for an optimized excavation scheme that will require additional data collection and modeling during remedial design so that a detailed excavation plan can be developed before construction begins. This will ensure that actual construction time is minimized, which will also minimize worker exposures, odors, etc.
Operable Unit 1 is in the Remedial Design phase. The remedial design phase is where the engineering and construction details are developed to implement the remedy. In accordance with the amended agreement, the PRPs submitted for EPA’s review and approval a Remedial Design Work Plan that included an overview of the remedial design process, description of specific elements of the design, and preliminary design schedule necessary to design the remedy selected in the Record of Decision Amendment. Click here to view: Remedial Design Work Plan West Lake Landfill Superfund Site Operable Unit-1. Another element of the design process will include design investigations involving collection of additional samples and other site-specific data required to implement the selected remedy. This investigation work began in October, 2020. Information collected during these investigations will allow for more precise planning and design for areas to be excavated and provide additional information needed to design the engineered cover that will be placed over the site once excavation is complete. Other remedial design work will include refinement of a 3-D model to support a detailed excavation plan; preparation of the engineering drawings to support excavation and cap construction; and preparation of a construction schedule. One of EPA’s top priorities is worker and public safety during construction, and the Remedial Design process plays an important role in achieving that objective.
The PRPs are implementing the remedial design according to the OU-1 Remedial Design Work Plan approved with modifications by the EPA on November 15, 2019. The PRPs are currently conducting the Remedial Design Investigation in accordance with the approved documents listed below:
DESIGN INVESTIGATION WORK PLAN WEST LAKE LANDFILL SUPERFUND SITE OPERABLE UNIT 1
FIELD SAMPLING PLAN WEST LAKE LANDFILL SUPERFUND SITE OPERABLE UNIT 1
QUALITY ASSURANCE PROJECT PLAN WEST LAKE LANDFILL SUPERFUND SITE OPERABLE UNIT 1
DATA MANAGEMENT PLAN WEST LAKE LANDFILL SUPERFUND SITE OPERABLE UNIT 1
PROJECT SAFETY, HEALTH, AND ENVIRONMENTAL PLAN (PSHEP) AND RADIATION SAFETY PLAN FOR OPERABLE UNIT 1
Operable Unit 2:
Operable Unit 2 (OU-2) is also currently in the Remedial Design phase. This is the phase where engineering and construction details are developed to implement the remedy. Similar to OU-1, this work also begins with preparation of a Remedial Design (RD) Work Plan, which was approved by the EPA in May 2020. Click here to view: OU-2 RD Work Plan. The RD Work Plan includes additional design investigations and planning submittals to support the design of the remedy selected in the OU-2 Record of Decision. Geotechnical sampling and analysis activities will take place as part of the design investigations to provide additional information needed to properly design the landfill capping system at the Inactive Sanitary Landfill portion of OU-2. Due to the proximity of the Inactive Sanitary Landfill to the southern edge of Area 2 of OU-1, there is frequent coordination between design teams for both operable units.
Because additional soil sampling activity is necessary as part of OU-1 to determine the extent of RIM on the south side of Area 2, some elements of the OU-2 Remedial Design have been put on hold, such as the Slope Stability Evaluation and Western Waste Limit Investigation Plan, Soil Borrow Area Investigation Plan, and the 30% Remedial Design. However, progress on the OU-2 Remedial Design is continuing while some actions are temporarily paused. Work related to OU-2 landfill gas monitoring, stormwater monitoring, and waste separation activities are ongoing.
Operable Unit 3:
Operable Unit 3 is in the Remedial Investigation phase. During this phase, investigations are planned and conducted to determine if groundwater is contaminated with site-related contaminants and the extent of any identified contamination.
The OU-3 work will generally include:
- Investigation of the impacts to the alluvial and bedrock aquifers;
- Refinement of the understanding of the complex hydrogeologic system at the site;
- Evaluation of background groundwater quality; and
- The use of predictive tools, frequently called “models,” to evaluate potential future impacts to groundwater.
The EPA approved the Remedial Investigation/Feasibility Study (RI/FS) Work Plan on October 27, 2020. Field sampling and investigation activities began in November 2020. The OU-3 field investigation will require installation of additionalgroundwater sampling points, in addition to the existing site wells, to develop a thorough monitoring well network and collection of groundwater data and related information from all wells to account for seasonal variability and to provide a robust data set. New monitoring wells will be added into the groundwater sampling program as they are completed. Following the groundwater remedial investigation, as warranted, remedial alternatives will be developed and evaluated in an OU-3 Feasibility Study.
The PRPs are implementing the remedial investigation and feasibility study according to the OU-3 Remedial Investigation/Feasibility Study Work Plan approved by the EPA on October 27, 2020. The following remedial investigation documents have been completed and approved and clicking on the document name links to the approved plan:
WEST LAKE OU-3 REMEDIAL INVESTIGATION/FEASIBILITY STUDY WORK PLAN
OU-3 RI/FS FIELD SAMPLING PLAN
OU-3 RI/FS QUALITY ASSURANCE PROJECT PLAN
PROJECTED DATES:
The dates projected under the Cleanup Progress section are tentative and subject to change based on a variety of factors. The current estimate for completion of the Remedial Design (RD) for Operable Unit 1 (OU-1) is October-Decemberr of 2024; however, that time frame is directly related to the quality and completeness of the documents submitted to the EPA as part of the RD and could be revised. The Remedial Action (RA) Process begins after the Remedial Design is complete. The beginning of the RA does not mean the start of excavation and the EPA does not currently have an estimate of when that will begin. There are multiple steps in the RA process before excavation, including procuring an RA contractor and getting an RA Workplan approved.