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North Penn Area 1
EPA Region 3 (Mid-Atlantic)
EPA ID# PAD096834494
15th Congressional District
Last Update: January 2015
Current Site Status
The U.S. Environmental Protection Agency is overseeing the cleanup of North Penn Area 1 (Site).
A total of 428 tons of contaminated soil were excavated from the Granite Knitting Mills (GKM) and the Gentle Cleaners properties. Also, a groundwater extraction system was installed at the GKM well which consisted of an extraction pump and conveyance piping, with direct discharge to the sanitary sewer. Currently, groundwater monitoring is being conducted.
In February 2005, the groundwater extraction system associated with the GKM well was shut down. Concentrations of PCE within this well were below the cleanup standard, but one of the monitoring wells, S1, located approximately 200 feet southwest and downgradient of the GKM well, showed elevated levels of PCE which reached concentrations as high as 8,300 ppb. Pumping contaminated groundwater from monitoring well S1 and discharging the groundwater to the sanitary sewer began in September 2008. EPA is currently conducting other field investigation activities to better characterize the increase of contamination in this well.
A Five-Year Review for the Site was completed in September 2008. During that review a short-term protectiveness statement was deferred until data regarding 1,4-dioxane and vapor intrusion was evaluated.
In December 2008 various samples were collected to evaluate 1,4-dioxane. This chemical was not detected in any of the samples, therefore eliminating it as a concern for the site.
An Explanation of Significance Difference (ESD) was published on May, 29, 2012. This ESD gives the Agency the opportunity to expand the remedy where it may deem necessary and recognize Institutional Controls at the Site
In September 2013 a Five-Year Review was completed for the site. No major issues were detected, and was determined that the remedy is functioning as designed to protect both human health and the environment. EPA is currently working on the installation of more monitoring wells to better define the plume at the site.
The North Penn Area 1 Site is located in Souderton, Montgomery County, Pennsylvania. The contamination of the Site was first noted in 1979 in the North Penn Water Authority (NPWA) well S9. The well was immediately taken out of service because of high tetrachloroethene (PCE) concentrations found in the groundwater. Sampling was conducted at several wells in the area to determine the concentrations of contamination in the groundwater. The following contaminants were identified: PCE, trichloroethene, 1,1,1-trichloroethane, 1,1-dichloroethane, 1,1-dichloroethene, and cis-and trans-1,2-dichloroethene. These contaminants were found in several wells at various times at levels up to 250 parts per billion (ppb).
The Site includes three facilities. The first facility, Gentle Cleaners, was known to use PCE, 1,1,1-trichloroethane, and other chlorinated solvents of unknown composition from 1953 to 1983. There is a documented spill of 75 gallons of PCE occurring in the early 1970s. In addition, discharge of PCE to a sink that drained into the same area of the spill. The second facility, Granite Knitting Mills (GKM), maintained a dry cleaning machine using PCE from 1967 to 1979. Wastes generated from the machine were estimated to contain about 2 percent PCE. The third property, Parkside Apartments, once included a dry cleaning establishment. Soil contaminated by PCE was found on all three properties during the Remedial Investigation. An estimated 75,000 people obtain drinking water from public and private wells within 3 miles of the site.
- Site Responsibility
- This Site is being addressed through federal and state actions. Operation and maintence (O&M) activites for the Site were transferred to Pennsylvania Department of Environmental Protection (PADEP) in December 2008.
- NPL Listing History
- This Site was proposed to the National Priorities List of the most serious uncontrolled or abandoned hazardous waste sites, requiring long term remedial action on January 22, 1987. The Site was formally added to the list March 31, 1989, making it eligible for federal cleanup funds.
Threats and ContaminantsThe groundwater is contaminated with several Volatile Organic Compounds (VOCs), such as PCE, trichloroethylene (TCE), 1,1,1-trichloroethane, 1,1-dichloroethane, 1,1-dichloroethene, and cis-and trans-1,2-dichloroethene. These contaminants were found in several wells at various times at levels up to 8,300 parts per billion (ppb). Similar contaminants have been detected in soil. However, for both groundwater and soil, the most prevalent contaminant detected in the samples has been PCE.
Contaminant descriptions and risk factors are available from the Agency for Toxic Substances and Disease Registry, an arm of the CDC.
On September 30, 1994, EPA issued a Record of Decision (ROD) selecting the remedy for the Site. The remedy included the removal and off-Site disposal of contaminated soil from the three properties of concern and extraction and treatment of groundwater. Groundwater was to be extracted from the GKM well and from the NPWA well (S9). A design for implementing this remedy was completed in September 1996. Results from soil sampling conducted during the design showed levels of contamination below the remediation goals established in the ROD for the Parkside Apartments property. Therefore, no remedial action was planned to be conducted on this property. In addition, groundwater sampling results revealed low levels of contamination in the wells sampled, therefore, groundwater was to be discharged to a publicly owned treatment works instead of treating it with an air stripper. On October 29, 1997 an Explanation of Significant Differences (ESD) was signed for the purpose of documenting EPA's decision not to pump water from well S9. This decision was based on the low PCE levels detected in this well during the remedial investigation and the remedial design sampling activities, as well as, a change in the Commonwealth of Pennsylvania's remediation standards.
Construction of the remedial action, as outlined in the ROD, with the changes included in the October 29, 1997 ESD, was completed on July 13, 1998. A total of 428 tons were excavated from the GKM and the Gentle Cleaners properties. Also, an extraction system was installed at the GKM well which consisted of an extraction pump and conveyance piping, with direct discharge to the sanitary sewer. On September 24, 1998, a second ESD was issued for the site to document EPA's decision that the interim action implemented for OU2 should be the final action. This decision was based on the low levels of contamination that were detected in the wells.
In February 2005, the groundwater extraction system associated with the GKM well was shut down. Concentration of PCE within this well were below the cleanup standard, but one of the monitoring well, S1, located approximately 200 feet southwest and downgradient of the GKM well, showed elevated levels of PCE which reached concentrations as high as 8,300 ppb. In the Spring of 2006, EPA conducted a pumping test for seven days in this well. Based on the results of the pumping test, EPA determined that pumping of this well for a longer period of time should be conducted. Pumping contaminated water from monitoring well S1 and discharging the groundwater to the sanitary sewer began in September 2008. EPA is conducting other field investigation activities to better characterize the increase of contamination in this well. A vapor intrusion investigation of nearby homes was performed in spring 2009 and additional follow-up sampling at some of these homes was completed in January 2010. Based on the analytical results, it is EPA's determination that vapor intrusion is not an issue for the homes and businesses in the vicinity of the Site. A Five-Year Review for the Site was completed in September 2008, and EPA is currently preparing a Five-Year Review Addendum.