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Sand, Gravel and Stone

Community Newsletter Update
December 2003

Additional Information

The U.S. EPA has many public documents on the topic of water quality. For example, there is a recent document entitled "Drinking Water from Household Wells" (EPA 816-K-02-003, January 2002). This document and others are available for free from the EPA Office of Groundwater and Drinking Water. Inquiries can be made to the Safe Drinking Water Hotline (800) 426-4791, or documents can be viewed or downloaded from the EPA web site at:

http://water.epa.gov/drink/index.cfm

If you have any additional questions regarding the quality of private well-water, please contact the Cecil County Health Department at (410) 996-5160.

For further information about the MSGS Site, we encourage you to contact Trish Taylor, EPA Community Involvement Coordinator, at (800) 553-2509 and Debra Rossi, EPA Project Manager, at (215) 814-3228.

EPA's Administrative Record file for this Site may be viewed at:

http://www.epa.gov/arweb/

Background

Last fall, the Cecil County Health Department, in conjunction with the U.S. Environmental Protection Agency (EPA), offered free well-water tests for residents of the Paradise Pines neighborhood and other surrounding areas near the Maryland Sand, Gravel and Stone Superfund Site (MSGS Site). Though low levels of three chemicals were found in some wells, all residential wells met the Federal limits for drinking water set under the Safe Drinking Water Act. While the residential well sampling did not indicate a connection between these low levels and the MSGS Site, EPA asked the MSGS cooperating companies to further investigate the subsurface soils and groundwater primarily near the eastern edge of the Site. The companies agreed to conduct the investigation under an EPA-approved work plan.

Beneath the MSGS Site, groundwater is present in four layers - the Upper Sand, Middle Sand, Lower Sand and Bedrock aquifers. The Upper Sand, Middle Sand, and Lower Sand aquifers are part of a geological formation called the Potomac Group. The Upper Sand is the shallow aquifer (nearest to the earth's surface) and it ends near the edge of the Site. Although it is affected by Site contaminants, the shallow groundwater is being captured by extraction trenches and treated on-site. Beyond the Site, groundwater may include Potomac Group aquifers (such as the Middle Sand and Lower Sand) and Bedrock. Most residential water wells in the vicinity of the Site are located in the Lower Sand or Bedrock aquifers.

Groundwater Investigations

The subsurface soil and groundwater investigation was conducted between January 20 and April 7, 2003. It confirmed historical information concerning the Lower Sand and Bedrock groundwater flow direction and quality. Site-related chemicals have not been found in the groundwater in these units (where most residential wells are located) at levels that pose a threat to public health or the environment.

New information was developed on groundwater flow direction and quality in the Middle Sand aquifer. East of the MSGS Site, the Middle Sand groundwater flows southeast into the eastern branch of Mill Creek. The investigation found that groundwater and chemicals from the Upper Sand aquifer have seeped down into the Middle Sand aquifer near the eastern property boundary. Three wooded properties adjacent to the Site have impacted groundwater. This groundwater flows southeast into the eastern branch of Mill Creek. The area with impacted groundwater is within the "Next Phase Study Area" shown in the figure on page 3 of this newsletter.

Based on these results, the groundwater monitoring program was expanded to help safeguard well water as Site groundwater is cleaned up. Three additional Middle Sand monitoring wells and two additional off-site drinking water wells were added to the groundwater monitoring program. EPA also approved the next phase of the groundwater investigation which is now underway.

The primary objectives of the next phase of the groundwater investigation are to:

  1. find the leading edge of the affected groundwater, and
  2. gather information needed to develop cleanup plans for the affected Middle Sand groundwater.

These objectives will be addressed by adding at least seven new monitoring wells and evaluating four rounds of sampling data collected over a one-year period. Results of this investigation will help EPA and the Maryland Department of the Environment (MDE) to determine if any additional measures are needed to address the Middle Sand groundwater.

After all the results have been evaluated by federal and state agencies, EPA will make them available to the public and local officials for review. We expect the results to be available to the public in winter 2004.

Prior Cleanup Actions

Under the direction of EPA, the cooperating companies have already done significant work at the Site to investigate and address affected Site groundwater. Under a previous agreement with EPA, the companies installed an on-site system to capture and treat affected groundwater. The affected groundwater is present primarily in the shallow aquifer nearest to the earth's surface. This on-site system has operated for about seven years, collecting and treating around 82 million gallons of Site groundwater so far.

Next Steps

On September 29, 2003 EPA issued "Special Notice" Letters to companies believed to be potentially liable at the MSGS Site under the Superfund law. These letters start the negotiation process for the next part of Site cleanup. EPA expects to work with the cooperating companies to create a legal document that outlines an agreement and work timeline. This cleanup was discussed at public meetings last year, and is briefly described below. Once negotiations are completed, an engineering and design phase will take place prior to Site cleanup.

Impacted soil, sediment and wastes within the fenced Site area will be excavated and cleaned using thermal desorption (heating to high temperatures). Approximately 30,000 cubic yards of soil, sediment and wastes will be treated. Heating the materials will cause contaminants to vaporize. These vapors will be contained and treated to remove contaminants. Excavated areas will be backfilled with clean soil and grass will be planted. Approximately 1,000 cubic yards (roughly 60 truckloads) of material that cannot be treated with thermal desorption will be disposed of off-site at EPA permitted treatment facilities.

Also, the existing groundwater recovery trench system (which is now treating the shallow contaminated groundwater) will be upgraded. Safe, natural substances, such as molasses or oxygen, will be added to the groundwater to encourage soil microbes to "eat" the chemicals in the groundwater. To prevent any activities from interfering with the groundwater treatment, and to prevent drinking or showering with the groundwater on-site until it meets safe standards, temporary land-use controls will be put in place.

Site Map

Typical Groundwater Aquifers

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