Analytical results from samples collected by the EPA during the PA and RA indicate that hazardous substances have been released into the environment. PCE and TCE were detected in soil, groundwater and air samples, and have exceeded RALs and screening levels.
On August 21, 2013, a time-critical removal Action Memorandum with a 12-month exemption was signed for the Highway 3 PCE Site. The removal action addresses immediate threats to public health, welfare and the environment posed by the Site.
2.1.2 Response Actions to Date
Indoor air and sub-slab soil gas sampling was conducted to support a removal assessment on May 9 and 10, 2016. Removal assessment activities involved collection of the following samples:
(1) indoor air samples within buildings near suspected source areas or overlying the PCE plume, and
(2) sub-slab soil gas samples for analysis for soil gas vapors from beneath building foundations near
suspected source areas or overlying the PCE plume.
Eight indoor air samples were collected in 1-liter Tedlar bags at locations within businesses in close
proximity to the site (see Appendix A, Figure 4). The samples were collected within basements at most
locations, including one business where a vapor mitigation system had been installed as part of an EPA
removal action. The samples were collected as grab samples by use of a low-volume sampling pump.
The indoor air samples were generally collected over a 1-minute sampling period. Access for collection
of indoor air samples was denied at two businesses: Perfect Image at 18 Plymouth Street SW, and Piece
of Cake at 25 Central Avenue SW.
Sub-slab soil gas sampling involved collection of six samples from ports installed during previous
sampling events at businesses and residential dwellings (see Appendix A, Figure 4). All sub-slab soil gas
samples were collected in 1-liter Tedlar bags as grab samples by use of a low-flow sampling pump (over a
1- to 2-minute sampling period). None of those samples were collected within buildings where vapor
mitigation systems had been installed. To ensure integrity of the sub-slab ports, a small swab wetted with
70 percent isopropyl alcohol (IPA) was placed within 4 inches of each port during sample collection.
Detection of IPA in a Tedlar bag sample would indicate a leak in the port. Figure 5 in Appendix A is a
sketch of one basement area (121 1st Avenue NW) where five sub-slab ports had been installed (and
sampled during the May 2016 activity).
At each sample location, a real-time reading for non-specific VOCs was obtained by use of a RAE
Systems ppbRAE Plus photoionization detector (PID), and temperature and barometric pressure were also
noted. All field measurements were recorded in a field logbook. The indoor air and sub-slab soil gas
samples collected in Tedlar bags were analyzed by the EPA Region 7 mobile laboratory (mobile
laboratory), which was temporarily stationed at the PCE Chestnut Street site in Atlantic, Iowa. Table 1
summarizes addresses, business names (if applicable), sample types, and field readings for the indoor air
and sub-slab soil gas samples.
2.1.3 Enforcement Activities, Identity of Potentially Responsible Parties (PRPs)
Currently a PRP has not been identified.
2.1.4 Progress Metrics