CD Maryland Sand, Gravel and Stone Superfund Site Elkton, Cecil County, Maryland % WJ W .iW Aquifer Study Completed The First Phase In 2002, EPA asked the cooperating companies for the Maryland Sand, Gravel and Stone Superfund Site (MSGS Site) to expand their monitoring program for the deeper groundwater aquifers at the Site. In response, the companies conducted a comprehensive groundwater study, involving several planning and data collection phases. Groundwater samples were collected from 74 new locations in the Middle Sand Aquifer during the course of the investigations. In addition, permanent monitoring wells were installed at 30 of these locations. The groundwater study activities and results for each of the three phases are listed below. The first phase of field work was conducted from January to March 2003. This work included: • Confirming that the Lower Sand Aquifer and Bedrock Aquifer are free of contamination, and • Identifying a gap in the clay layer separating the Upper Sand Aquifer and the Middle Sand Aquifer along the eastern side of the Site. • Contaminants in the Upper Sand Aquifer have moved downward through this gap into the Middle Sand Aquifer and are migrating southeast, with the flow of groundwater. • Contaminants include: benzene; chlorobenzene; 1,4-dioxane; tetrachloroethene (also called PCE, or perc); and trichloroethene (TCE). Aquifer study phases continue on page 2. ------- Aquifer Study (Continued...) The Second Phase The second phase, conducted from November 2003 to February 2004, produced new information identifying the extent of contamination in the Mi ddle Sand Aquifer beneath the eastern portion of the Site. The Third Phase The third phase involved several periods of field work between August 2004 and August 2006. This phase resulted in: • Identifying an additional groundwater plume beneath the northwestern portion of the Site in the Middle Sand Aquifer, and • Updating the contour of the eastern plume. Identical contaminants have been found in both plumes. Ground Surface SmmSBm •*. «V V V V V-Y"V V S • S ¦ <1- ¦ - Typical Water Supply Wells UPPER SAND MIDDLE SAND LOWER SAND Hi m l : 'IW-LItWv BEDROCK AT THE SITE NEAR THE SITE Nearby residential wells have been tested and will continue to be monitored during cleanup activities. To date, all private well water tested has met Federal Safe Drinking Water Act standards. The data collected from the groundwater study is being used to develop a cleanup work plan for the two groundwater plumes found in the Middle Sand Aquifer. Construction Scheduled for Fall 2007 The Upper Sand Aquifer is shallow- nearest to the earth's surface) and ends near the edge of the Site. The ground- water in this aquifer is contaminated and is being collected by extraction trenches and then treated. An extraction trench system was built onsite in 1996 and has treated over 130 million gallons of groundwater. In fall 2007, the Site's trench system will be upgraded with the construction of an additional trench. The new trench will supplement the existing three extraction trenches to help maximize the amount of contaminated shallow groundwater intercepted and treated. ------- Soil Cleanup Remedy Background Soil samples have shown various levels of contamination in different areas on the Site property. The soil cleanup design will include excavation of on-site contaminated soils for: • on-site thermal treatment and/or • off-site disposal, depending on the composition and levels of contamination detected. Thermal treatment involves heating the soil to high temperatures, causing contaminants to vaporize. Vapors are captured and treated to meet state and federal air regulations. Shallow Groundwater Aquifer Cleanup The cleanup design for the Site will also address the Upper Sand Aquifer, or "shallow groundwater." The cleanup plan involves a double approach to the groundwater cleanup. The first part is to continue collecting and treating the groundwater using the upgraded interception trench system. The second part is to increase the concentrations of oxygen throughout the aquifer in order to enhance natural biodegradation of both soil and groundwater contaminants. Next Steps Once the cleanup plans are finalized, the next steps include: \/ Preparing the soil for removal. In order to facilitate soil excavation, workers will first need to lower the water table within the Upper Sand Aquifer onsite. 7 Excavating the contaminated soil and treating it onsite. Soil that meets the treatment standards will be backfilled. A small portion of the soil will need to be transported to a proper facility offsite for disposal. 7 Aeration of the Upper Sand Aquifer in order to promote and encourage the biodegradation of groundwater contaminants. The MSGS Site in Elkton, Maryland is a former sand and gravel quarry. From the late 1960s to the mid-1970s, portions of the Site were used for industrial waste disposal. A group of 40 Potentially Responsible Parties (PRPs) signed a consent decree (effective June 2005) with EPA, agreeing to conduct the cleanup for the Site. The design plans for contaminated onsite soils and shallow groundwater are currently being developed. Beneath the MSGS Site, groundwater is present in four layers: ~ The Upper Sand Aquifer, ~ The Middle Sand Aquifer, ~ The Lower Sand Aquifer, and ~ The Bedrock Aquifer. Most private wells in the area pump water from groundwater sources away from the Site (such as the Lower Sand and Bedrock Aquifers). Residential wells will continue to be tested throughout cleanup activities. For Additional Information ; For more information about the Maryland Sand, : Gravel and Stone Superfund Site, please contact: : Trish Taylor ; Community Involvement Coordinator :215-814-5539 : tavlor.trish@epa.gov ; Debra Rossi : Remedial Project Manager ;215-814-3228 ¦ rossi.debra@epa.gov : Peter Gold State & Congressional Liaison Officer i 215-814-5236 : gold.peter@epa.gov : Additional information is also available on the internet: www.epa.gov/reg3hwmd/super/sites/ :MDD980705164/index.htm ------- U.S. Environmental Protection Agency 1650 Arch Street (Mail Code 3HS52) Philadelphia, PA 19103 Attn: Trish Taylor ------- |