2.1.1 Narrative
In conducting downgradient sampling pertaining to another Superfund site in the area (the PCE/TCE Northeast Contamination site, f.k.a. as the York Northeast Groundwater site), a distinct groundwater contaminant plume in York was discovered by the U.S. Environmental Protection Agency in the fall of 2010. Concentrations of PCE ranging from 9.6 to 32 µg/L were found in private drinking water wells. One well also contained TCE at a concentration of 5.9 µg/L. The EPA MCL for PCE and TCE in drinking water is 5 µg/L.
The EPA is continuing to provide an alternative water supply to
residents, conduct vapor intrusion sampling, and install vapor mitigation
systems where necessary. Additionally, the EPA is conducting additional soil
and groundwater sampling, attempting to identify source areas and further
delineate the groundwater plume.
2.1.2 Response Actions to Date
Approximately 40 locations were identified for groundwater sample collection and five locations for soil sample collection. On Monday, November 1, 2015, the EPA mobilized to the site to begin collecting groundwater and soil samples, indoor air samples and to install vapor intrusion ports. The EPA mobile laboratory was also on site to analyze groundwater samples in real time to allow movement of sampling locations to better define the groundwater plume.
Seventy-seven groundwater samples were collected for analysis from approximately 36 locations. Samples were analyzed in the mobile lab and confirmation samples were also sent to the Region 7 EPA laboratory. The table showing groundwater sample results can be found in the document section labeled "Groundwater Sample Results - updated 11-7-15". The highest reading for PCE was 160.4 µg/L, and the highest reading for TCE was 56.6 µg/L. Based on the sample results the highest concentration for PCE was farther north than anticipated at location TW15-85 33-37 fbgs. (A map of sampling locations can be found in the document section labeled "Groundwater Sample Results Map - updated 11-7-15". ) Further soil and groundwater sampling will be conducted in this area the first week of December 2015.
Approximately 20 soil samples were collected from 5 locations. Soil samples were sent to the Region 7 EPA laboratory for analysis.
Approximately 20 indoor air samples were collected and sent to the Region 7 EPA laboratory for analysis. Subslab soil vapor ports were installed in five properties.
The EPA gave a presentation on the site at the Sunrise Sertoma Club on November 2, 2015.
2.1.3 Enforcement Activities, Identity of Potentially Responsible Parties (PRPs)
The PRP search is ongoing. No PRP has been identified to date.
2.1.4 Progress Metrics
- Collected
approximately 112 indoor air samples.
-
Collected
approximately 227 subslab soil gas samples.
Installed 17
vapor mitigation systems.
Collected
approximately 323 groundwater samples to further delineate the groundwater
plume (since 2014).
Oversaw
installation of a water main to hook approximately 10 residences to city water.
Connected
approximately 16 residences to city water (since 2014).
Collected
approximately 60 soil samples to assist in finding source areas.
- Sample results tables can be found in the document section.
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