DERR-2024-008634

195 North 1950 West • Salt Lake City, UT
Mailing Address: P.O. Box 144840 • Salt Lake City, UT 84114-4840
Telephone [phone] • Fax [phone] • T.D.D. [phone]
www.deq.utah.gov
Printed on 100% recycled paper
State of Utah

SPENCER J. COX
Governor

DEIDRE HENDERSON
Lieutenant Governor
Department of
Environmental Quality

Kimberly D. Shelley
Executive Director

DIVISION OF ENVIRONMENTAL
RESPONSE AND REMEDIATION

Brent H. Everett
Director

ERRC-094-24

July 2, 2024

Bruce Bastian
Paxton Project LLC
2483 North Canyon Road
Provo, Utah 84604

Re: Review Comments - Site Characterization Work Plan and Quality Assurance Project
Plan for The Paxton - Voluntary Cleanup Program Site #129
Salt Lake City, Salt Lake County, Utah

Dear Mr. Bastian:

The Division of Environmental Response and Remediation (DERR) has reviewed the
following documents as required by the provisions of the Voluntary Cleanup Program (VCP):

● Geosyntec Consultants, Site Characterization Work Plan- Paxton Development, dated
May 2024; and,
● Geosyntec Consultants, Quality Assurance Project Plan- Paxton Development, dated
May 2024.
Based on the review, the DERR has attached technical comments pertaining to the above
documents. Please work with your environmental professional to address the comments and submit
revised documents for review.

Thank you for your participation in the VCP. If you have any questions, please contact me
at [phone].
Sincerely,

Allison Stanley, Project Manager
Division of Environmental Response and Remediation

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AS/tt

Enclosure: Technical Comments

cc: Brent Robinson, Geosyntec Consultants
Dorothy Adams, Executive Director, Salt Lake County Health Department
Ron Lund, Environmental Health Director, Salt Lake County Health Department
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DERR Comments on the Quality Assurance Project Plan (QAPP) and Site Characterization
Work Plan (SCW) - The Paxton VCP Site #129

General Comments on the SCW:
1. Since characterization activities are not proposed under the buildings and other hardscape
locations in the Site Characterization Workplan (SCW), further sampling should be
proposed in the Remedial Action Plan (RAP) once the buildings have been demolished and
the foundations/hardscape removed. Due to the age of the Site, potential unknowns may
exist under the buildings beyond the reported hydraulic lifts. An environmental professional
should be on-site as these surfaces are removed.
2. It is acceptable to screen against the Initial Screening Levels (for TPH-DRO/GRO and
TRPH only). However, the Initial Screening Levels are conservative. To better evaluate the
potential risk and address any uncertainty, the Applicant is encouraged to Fractionate the
highest concentrations using the UST Fractionation method.
3. Trichloroethylene (TCE) was reported to exceed the soil screening level in GP-4 from 6-7
feet below ground surface (bgs). However, the source of this contaminant is unknown. To
address this uncertainty, please propose further sampling to define the nature and extent of
contamination. This information will be necessary to help develop a remedy.
4. It appears the proposed sampling will be conducted prior to the removal of the debris from
the Site. Until the Site is cleared and inspected, it should be assumed there are possible
unknowns across the property that will warrant additional characterization. To address this
comment, please include opportunity samples in the SCW and clearly state that the Site will
be inspected and additional sampling conducted, as needed, prior to designing a remedial
action.
5. To better understand the potential risk at the Site and design a future vapor mitigation
strategy, soil gas samples or sub-slab samples should be collected. It is acceptable to conduct
this sampling after the next round of groundwater data is collected so data can be reviewed
and samples can be biased toward the future building footprint and areas of highest
contamination.
Specific Comments on the SCW:
1. Table of Contents- Figure 1 depicting the Site location is referenced in the SCW but is not
attached to the document. Please attach the figure.
2. Section 1.2, sentence 5- The Site was not accepted into the VCP on April 3, 2024, but rather
on April 1, 2024, when the DERR signed the VCP eligibility letter. Please correct this date
in the text.
3. Section 1.3, sentence 25- Metals were not analyzed in the groundwater at monitoring well
MW-3 but at sampling point GP-1. Please correct this statement in the text.
4. Section 1.5, sentence 6- It is premature to indicate that an updated round of groundwater
sampling will allow the Site to move directly into the RAP. Please clarify the last sentence
by adding the statement, “to evaluate the need for potential further characterization and/or
remedial action”.
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5. Section 1.5, sentence 7- The SCW discusses detailed delineation near the “unknown vault”;
however, this was identified to be an in-ground lift in Section 1.3. Please use consistent
language throughout the document when referring to this structure.
6. Section 1.5, sentence 7- The SCW notes that confirmation samples will be collected
following the removal of impacted soils as part of the RAP. Please be aware that the purpose
of the SCW is not to outline a remedy for the Site. This will be done in the final RAP. The
DERR will need to review the characterization data before evaluating a final remedy for the
site.
7. Section 2.1, sentence 5- The SCW does not identify where the four deeper soil samples (6-
12” bgs) will be located. Please indicate in the text if these sample locations are already
determined and where, or if they will be identified in the field. Additionally, please indicate
if these samples will be collected from previous locations, such as SS-1.
8. Section 2.8, sentence 1- Since screening levels may change throughout the project, please
indicate that data will be compared to the “most current” Screening Levels to ensure that
project objectives remain protective of human health and the environment.
9. References- The date of the project QAPP is May 2024. Please correct this date in the listed
reference.
10. Appendix A, Table 1A- There are still some transcription errors in the historical data table.
The transcription errors are found for GP-1 through GP-4, as the results for 1,1-
dichloroethene and cis-1,2-dichloroethene are switched. Please see the limited subsurface
investigation from September 2023 for the correct lab results.
General Comment on the QAPP:
1. One of the last elements of EPA’s Quality Assurance guidance is the reconciliation with user
requirements. Please include this section and discuss how data and information will be reconciled
with the project objectives to assess the overall success of sampling activities.
Specific Comments on the QAPP:
1. Section 1.1, sentence 8- Similar to the SCW, the Site did not enter the VCP on April 3, 2024,
but rather on April 1, 2024, when the DERR signed the eligibility letter. Please correct this
in the text.
2. Section 2.9.5, sentence 10- Please revise the text to note that groundwater concentrations
will be screened against EPA RSL Tapwater values if there is no MCL. This includes
compounds such as 1, 4 Dioxane.
3. Section 3.2, Table 1- To ensure that procedures are properly met when collecting samples,
please provide a Standard Operating Procedure (SOP) for general sample labeling, handling,
custody, and documentation or specify where in the QAPP this information is clearly
articulated.
4. Section 3.6, sentence 15- Please revise the QAPP to indicate the frequency of the rinsate
blank collection will be specified in the SCW.
5. Section 4.4, sentence 1- Please revise the text to specify the individual responsible for
conducting the data verification and validation, and how data reviews will be presented in
final documents submitted under the VCP. Data review summaries should be included as
part of the final reports detailing the investigations and cleanup and usability of the data. If
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laboratory and field corrective actions are required, the consultant should coordinate with
the DERR.
End of DERR SCW and QAPP Comments