Little Elk Creek, Elkton, MD

A.36 Little Elk Creek, Elkton, MD

A.36.1 Contacts

Regulatory Contacts:

John Epps,

215-814-3144

[email protected]

Kim Lemaster

410-537-3440

[email protected]

A.36.2 Summary

Environment:	Creek
Scale:	Full
Contaminants of Concern:	Solvent DNAPLs
Source Control Achieved Prior to Remedy Selection?	Groundwater pump and treat implemented at same time as stream remedy
Final Remedy:	Excavation, low permeability1) Characteristic of a material or membrane that allows liquids or gases to pass through it; 2) The rate of flow of a liquid or gas through a porous material. capA covering over material (contaminated sediment) used to isolate the contaminants from the surrounding environment.

A.36.3 Site Description

The Galaxy/Spectron Inc., Little Elk Creek, site is located on approximately eight acres near Elkton, Maryland, in a rural residential area. Both light and dense NAPLs (LNAPLs and DNAPLs, respectively) were released while the solvent recycling operation was active, resulting in contaminated soil, overburden groundwater, bedrock groundwater, and DNAPL seeps along the western bank of Little Elk Creek.

The site was operated as a paper mill until it was destroyed by fire in 1954. Solvent recycling operations occupied the site from 1962 to 1988. The liquid materials processed at the facility included volatile organic compounds (VOCs) such as chlorofluorocarbons, halogenated ethenes and ethanes, chlorobenzenes (denser than water), and various alkanes and aromatic hydrocarbons (less dense than water).

CSM summary: The CSM indicated residual DNAPL in the shallow soil being released from an unlined storage lagoon and leaks from the processing equipment. Contamination at the site was released into the soil, and much of it migrated into the fractured bedrock. Once DNAPLs enter the groundwater, they act as a major source of groundwater contamination (via dissolution) and surface water contamination (due to discharge of contaminated groundwater and/or movement of DNAPLs). Site receptors include individuals who may be exposed to the contaminants in the soil and groundwater.

A.36.4 Remedial Objectives

Numerous organic and inorganic chemicals pose threats to human health and ecological receptors in Little Elk Creek. USEPA has established the following RAOs to mitigate and/or prevent existing and future potential threats to human health and the environment:

Continued operation and maintenance of the constructed groundwater containment system, so that federal AWQC for consumption of fish and drinking water are not exceeded within Little Elk Creek, immediately downstream of the groundwater containment system. This action is necessary to address potential risks to human health and ecological risks that may occur if the operation were discontinued and contamination were to enter Little Elk Creek.
Continued operation and maintenance includes ensuring that the groundwater treatment plant has adequate capacity. The maintenance of the liner is also necessary to prevent the re-establishment of the seeps along the creek banks, which existed prior to the installation of the liner.

A.36.5 Remedial Approach

Final selected remedy: Excavation, low permeability cap, and groundwater treatment

Approximately 2,000 yd³ of affected stream sediments were excavated from Little Elk Creek in 1998, and a Stream Isolation/Ground Water Collection and Treatment System (GWTS) was constructed in 1999 to contain and intercept VOC-bearing groundwater from the overburden and bedrock thereby eliminating discharge to the stream. The stream isolation used an engineered cap consisting of a polyethylene membrane-backed geosynthetic clay liner (GCL), Bentomat CL™. The GCL was overlain by a geotextile and gabion basket with stone and sand fill for erosion protection.

Additional upland actions included a RCRA modified cap and in situ chemical reduction treatment of groundwater.

USEPA has determined that the selected remedy provides the best balance of tradeoffs among the balancing criteria (long-term effectiveness and permanence; reduction in toxicity, mobility, or volume through treatment; short-term effectiveness; implementability; and cost) while considering state and community acceptance.

A.36.6 Monitoring

Collected groundwater is treated, and thus monitored prior to discharge to Little Elk Creek, to comply with the requirements of the NPDES program and the Maryland discharge limitations and monitoring requirements of 100 ppb total VOCs.

Routine sampling is performed in the creek immediately downstream of the groundwater containment system for VOCs and semi-VOCs. Federal Ambient Water Quality Standards for consumption of fish and drinking water are required to be met in Little Elk Creek.

RAOs/project objectives achieved? The seeps have been continually captured and treated by the stream isolation/GWTS and no longer contribute to contamination in the creek. Because of the improvements in stream water quality due to the stream isolation/GWTS, restrictions on the use of the stream have been removed.

A.36.7 Costs

The geosynthetic clay liner material cost was $35,000. The annual operation and maintenance cost (in 2004 dollars) for the groundwater treatment system was estimated at $360,000.

A.36.8 Advantages and Limitations

Site-specific challenges at this site include the following:

Regulatory—The Maryland Department of Environment (MDE) believed that an upland RCRA modified cap was necessary to minimize the impact of infiltration on groundwater treatment.
Technical—After a storm in 2000, the groundwater treatment system was found to be undersized causing the creek liner to become buoyant until the pressure on the liner could be relieved. To correct the situation, the groundwater system treatment capacity was increased three-fold, pumped groundwater storage capacity added, and a RCRA modified cap was installed upland to minimize infiltration.
Community—The local community has not commented specifically on the selected alternative but generally stated its concern for safety of drinking water, a quick cleanup of the site, and a future use that may benefit the community.
Acceptance—The USEPA believes the selected remedy addresses many of the issues raised by the MDE and local community. The selected remedy helps protect drinking water, provides flexibility for future use, and could be implemented quickly.

A.36.9 0 References

U.S. Environmental Protection Agency, Mid-Atlantic Superfund, NPL Fact Sheet, Spectron Inc. http://www.epa.gov/reg3hwmd/npl/MDD000218008.htm.

U.S. Environmental Protection Agency, Region 3, Spectron Inc. Superfund Site Record of Decision Operable Unit 1, Sept. 2004. http://www.epa.gov/reg3hwmd/npl/MDD000218008/rod/2004-09-16/20040916Spectron%20RODFINAL.pdf.

Maryland Department of Environment, Facts about Galaxy/Spectron Site (NPL site). http://www.mde.state.md.us/assets/document/brownfields/spectron.pdf.

Publication Date: August 2014

Permission is granted to refer to or quote from this publication with the customary acknowledgment of the source (see suggested citation and disclaimer).