EPA has been asked to investigate tetrachloroethylene (PERC) contamination in Hyattsville (Chillum), Maryland and Washington, District of Columbia. PERC contamination was discovered during an on-going investigation of a gasoline-products release from a service station located in Hyattsville near the Chillum PERC property. The site under investigation includes a dry cleaning facility and a residential community. The dry cleaning facility is located in Maryland and is immediately adjacent to the Washington, DC border. Groundwater flow flows from Maryland into Washington, DC, and one or more plumes of groundwater containing PERC may be present beneath the local residential community.
September 11, 2003:
EPA, START contractors, and DC-DOH were on site. Local residents were periodically present during activities. EPA and START contractors conducted development of the six small-diameter driven wells (SDDW) installed in July and August 2003. Development is commonly conducted to improve water quality and yield of the well by removing fine-grained material (e.g., silt and clay) which settled in the well and in the aquifer surrounding the well during installation. During this project, development was completed primarily by overpumping and to a lesser degree by surging. Due to the small, 0.75-inch inner diameter of the wells, peristaltic pumps and Teflon bailers were used to develop the wells.
September 15, 2003:
EPA and START contractors were on site. Local residents were periodically present during activities. EPA and START contractors collected active soil vapor, tap water, and groundwater samples. Active soil vapor samples were collected from the two permanent implants installed in August 2003. The samples were hand-delievered to a laboratory procured by START for analysis of volatile organic compounds (VOC), including PERC, by EPA Method TO-15. The samples collected by EPA were hand-delivered to the laboratory and analyzed within 12 hours of collection. The property owners collected split samples of the EPA samples to be analyzed by a separate laboratory procured by the residents.
Drinking water samples were collected on this date from two local homes. One sample was collected from a home located along Riggs Road near the intersection with Oglethorpe Street, and one sample was collected from a home located in the vicinity of Oglethorpe Street and 8th Street. All homes in the area are connected to local municipal water systems. The samples were forwarded via courier to a laboratory procured by START for VOC analysis by Contract Laboratory Program (CLP) Scope of Work (SOW) OLC03.2.
Groundwater samples were collected from the six SDDW installed by EPA and START. Samples from four of the wells were collected using a peristaltic pump using low-flow techniques (minimal water level drawdown). Water-quality parameters were recorded using a multi-parameter flow-through meter. Specific conductance, pH, dissolved oxygen, turbidity, temperature, oxidation-reduction potential (redox), turbidity, and water level were recorded every five minutes. Samples were collected after water-quality parameters stabilized over three consecutive readings. At a minimum, the three consecutive readings were within 0.1 units for pH, 3% for conductivity, 10 mV for redox, and 10% for turbidity and dissolved oxygen, and 4 inches for water level. The samples were forwarded via courier to a laboratory procured by START for VOC analysis by CLP SOW OLM04.3.
EPA Community Involvement Coordinator Vance Evans met with a local citizens' committee that is actively involved in the site investigation. Key discussion focused on, first, listening to their concerns, then, enlightening them about the Superfund removal program and encouraging effective use of its community involvement process.
A. START contractors will procure the services of a subcontractor to survey the monitoring wells in reference to a local fixed reference point of known elevation.
B. Attend public meetings and prepare presentations of completed, on-going, and planned activities in response to the PERC investigation.
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