DERR-2024-005770

Hqmilton
Assessments . Remediolion
Aprrl5, 2024
Mr. Nicole Chavez
Utah Dept. of Environmental Quality
Division of Environmental Response and Remediation
195 North 1950 West, lst Floor
salt Lake city, uT 84116
Re Report on Installing Sub-slab Monitoring Points, Collecting Vapor Samplings and Data
and Groundwater Samples at the Petro Mart V (Hoagies), located at2705 North 2000
West, Farr West, Utah
Facility ID #1200424, Release Site NAF
Dear Ms. Chavez
On March 7-8 and March 77-12,2024 Hanilton Environmental representatives collected the
following samples from the Petro Mart V (Hoagies) site located at 2705 North 2000 West, Farr
West, Utah:
o Two sub-slab vapor samples inside the convenience store.. One Ambient vapor sample outside the convenience store.o One inside vapor sample in the convenience store.o Groundwater samples and data from eighteen monitoring wells
Figure I in Appendix A shows Site Map with the approximate locations of the sampling locations
and monitoring wells.
Collection of Sub-Slab Vanor Samn les From Vanor Monitorinp Points ffMP)
Hamilton Environmental representatives used the H & P Mobile Geochemistry Inc. recommended
test procedures to collect the sub-slab vapor samples, and the indoor and outdoor samples (see
Appendix B)
Two Vapor Monitoring Points were installed on March 1,2024- These monitoring points replaced
the two monitoring points that were destroyed during the fire at the Petro Mart -5 site. On March
7,2024 two sub-slab vapor samples were collected inside the Petro Mart 5 Convenience Store.
485 West 1400 North . Orem, Utoh 84057 . (B0t) 361-2102 . Fox 224-1893
The sub-slab vapor samples were collected utilizing the same sampling procedure at each location,
as follows:
t Sampling trains were constructed to complete each sampling or testing procedure in
an approved professional industry manner.
o Tubes and gauges were installed to conduct Shut-in Test :
Vacuum was applied until gauge reached -1O,,Hg.
Gauge was observed for a minimum of I minute with no vacuum loss.
Shut-in Test passed in both locations.
Five probe volumes of air were purged from the sand pack surrounding the filter, plus
the internal volume of the length of tubing used in the probe, plus the internal volume
of the connector tubing. During the purging of both VMPs petroleum vapors were
observed. The flow rate for purging did not exceed 200 mllmin.o No water was observed in sub-slab vapor borings.
' The flow rate for sampling was set for 100-200 ml/min and took approximately 2.8-
3.2 minutes to fill each of the two 200 mL size Summa canisters with the samples
vapor.
Sub-slab air samples were submitted to H&P Mobile Geochemistry Inc. Carlsbad, Califomia on
March 13, 2024, accompanied with chain-of custody and. analyzed using the following vapor
analyses:
o Method EPA TO-15o Method Utah ApH
o ASTM D1945
Results - Sub-slab Intrusion Vapor Sampling
Hamilton Environmental has prepared the following table that compares the sub-slab vapor
samples collected on 3/1712020 and31712024.
TABLE A
Analyte 3h7/2020 3/712024
FRONT E CORNE MP
Benzene 6.5 uglm3 3.6 uglm3
Toluene 5.4 uglm3 160 uglm3
benzene <4.4 uglm3 <4.4 uglm3
lene Total <73,2 uglm3 19.7 ug/m3
<5.3 uglm3 <5.3
MTBE <18 ug/m3 <19
<100 uglm3 180 ug/m3
TPHv (C6) Aliphatics <100 uglm3 <100 ug/m3
Naphthalene
TPHv (C6-C10)