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The Arkansas Department of Energy & Environment – Division of Environmental Quality (“DEQ”) and United States Army, Pine Bluff Arsenal (“U.S.”) entered into a July 13th Consent Administrative Order (“CAO”) addressing actions associated with dense nonaqueous phase liquid (“DNAPL”) contamination. See LIS No. 23-057.
The CAO provides that the U.S. operates a facility (“Facility”) at the Pine Bluff Arsenal that:
. . . designs, manufactures and refurbishes smoke, riot control, and incendiary munitions, as well as chemical and biological defense operations items.
The Facility is in White Hall, Arkansas, and constitutes a Large Quantity Generator of Hazardous Waste. It is a Resource Conservation and Recovery Act (“RCRA”) permittee:
- Disposal of solid waste in a Hazardous Waste Landfill
- Storage of hazardous waste in a Phosphorus Storage Facility
- Storage of hazardous waste in a Solid Storage Facility
- Storage of hazardous waste in a Liquid Storage Facility
- Storage of hazardous waste in a Recovered Chemical Weapons/Munitions Storage Igloo
- Performance of post-closure care for the Hazardous Waste Landfill
- Corrective action for remediation of any releases of hazard constituents from Solid Waste Management Units
The U.S. is stated to have observed DNAPL in Phillips Creek on April 20, 2021. Notification was provided to DEQ regarding that observation and steps taken to remove it from the creek. Further, during the week of May 10, 2021, the U.S. reported to DEQ that no additional DNAPL had been observed in the creek since the initial discovery.
The U.S. submitted a letter to DEQ on June 3, 2021, describing the following:
- Discovery of DNAPL
- Clean-up response
- Laboratory analysis of the DNAPL
The laboratory analysis indicated that the DNAPL observed in the creek contained 10500 mg/kg of DDT and a total of approximately 240,000 mg/kg of trichlorobenzene, dichlorobenzene, and chlorobenzene compounds. The sample containing the crystalline substance contained 3070 mg/kg of DDT.
A subsequent observation of DNAPL in the same area was cited on June 16, 2021, with the approximate size referenced as five feet long with a maximum width of 12 inches and a maximum depth of four inches.
DEQ subsequently asked the U.S. to take the following actions in response to this additional discovery:
- Immediately clean up the DNAPL that was found in Phillips Creek;
- Provide DEQ with the interim measures Respondent will implement to protect human health and the environment and prevent the substance from moving downstream; and
- Provide DEQ with a plan to identify the source of the substance.
The U.S. informed DEQ on Jun 18, 2021, that the visible DNAPL had been removed from the creek and a possible source location identified. Concrete bags were stated to have been placed over the area where the DNAPL appeared to be entering the creek.
The CAO references a subsequent meeting between the U.S. and DEQ to discuss the DNAPL. Subsequent submissions of photographs identifying actions regarding the substance were provided. Additional observations of DNAPL and its removal are referenced on various additional dates.
On June 30, 2021, DEQ notified the U.S. by letter its conclusions regarding certain contamination at the Pine Bluff Arsenal that was contributing to levels of DDT and its degradants in sediment and fish tissue that are above the Remedial Action Decision Document screening levels for fish tissue along the creek as well as the Arkansas River near the mouth of the creek.
DEQ therefore requested that U.S. take certain additional sampling, interim measures, and prepare a RCRA Facility Investigation Work Plan.
DEQ required the implementation of certain interim measures and on July 14, 2021, the U.S. submitted its SAP for additional sampling of fish in the Arkansas River near the mouth of the creek and in a backwater area. Observations of DNAPL in the creek were reported by the U.S.
Additional analytical results (including additional sampling) were submitted to DEQ on August 31, 2021, which are stated to have indicated the concentration of DDT within the creek and exceed both the DEQ-permitted screening and FDA advisory levels.
The CAO notes that throughout the process the U.S. has met with DEQ weekly to discuss the various activities that are intended to limit the continued discharge of DNAPL into the creek and a RCRA Facility Investigation Work Plan.
Work referenced in the CAO is stated to have taken place from June 2021 to February 2022 which involved site characterization to further define soil quality impacts in a specified area. In addition, subsequent reports of DNAPL in the creek were submitted to DEQ on July 7, 2022, and July 8, 2022.
The U.S. submitted an interim measures work plan on July 27, 2022, which involved the installation of a check dam in Phillips Creek which was approved by DEQ. Work was begun on October 2022 on the construction of the diversion channel that was included in the interim measures work plan. Routine updates have been provided to DEQ.
A Description of Current Conditions (“DOCC”) for the Facility has been submitted to DEQ for which the agency provided comments. Revisions were submitted by the U.S.
The CAO outlines a schedule for certain actions that are required to be taken by the U.S. addressing:
- Implementation of the revised interim measures work plan
- Annual fish tissue sampling
- Submission of a RCRA Facility Investigation Work Plan (which shall be implemented upon approval)
- Submission of an RFI Work Plan which may include a Corrective Action Measures Study
A copy of the CAO can be downloaded here.
