DSHW-2024-009000

November 1, 2024
Blake Downey
Wasatch Environmental, Inc.
2410 West California Ave.
Salt Lake City, Utah 84104
RE:Approval of Additional Subsurface Investigation Report, PTI Property2970 South Richards StreetSouth Salt Lake, Utah84115UTCA-0067
Dear Mr. Downey:
The Division of Waste Management and Radiation Control (Division) has completed its review of the Additional Subsurface Investigation Report, PTI Property(Report) submitted on October8,
2024, by Wasatch Environmental, Inc. (Wasatch) on behalf of PTI Properties, LLC (PTI)for the Site located at 2970 South Richards Street in South Salt Lake City, Utah (Site).
Section 2 of the Report outlines the Site background and steps leading up to the additional investigation discussed in the Report. On July 25, 2024 Wasatch submitted the Lead Impacted
Soil Corrective Action Implementation Report (CAIR) outlining the removal of lead impacted soil in the former acid etching/plating tanks area. On August 1, 2024, the Division approved
the CAIR based on confirmation sample results exhibiting concentrations below the Residential Environmental Protection Agency (EPA) Regional Screening Level (RSL) and below a hazard
index of 1 and beneath the carcinogenic risk level of 1E-06.
Section 3 through Section 6 of the Report outlines the additional investigation to assess the nature and extent of constituents of potential concern (COPCs) identified at the Site. Potentiometric
data collected during field activities indicates that groundwater is flowing to the south-southwest with mounding observed near the southwest corner of the on-Site building. The Report
indicates that the mounding is “possibly due to leaking water supply pipes.” After review of the groundwater data, the Site appears to be a source of nitrates and volatile organic compounds
(VOCs) from historical Site operations. Additionally, several per and polyfluoroalkyl substances (PFAS) were identified on-Site. While the upgradient well indicates that PFAS is migrating
onto the Site, groundwater data indicates that PFAS concentrations increase in the vicinity of the nitrate and VOC source areaindicating that the Site might also be a source of PFAS.
The Report indicates that the shallow groundwater is an incomplete exposure pathway as it is not utilized as a potable water source and subsequently will not be ingested. While the groundwater
may not be a potable water source eliminating the ingestion pathway,a potentiallycompleted exposure pathway may be present for both Site occupants and environmental receptorsas COPCs
volatilize and potentially flow into Millcreek. COPC sub-slab vapor concentrations identified in the Soil Gas Sampling Report dated June 4, 2020, exceeded the Industrial EPA Vapor Intrusion
Screening Level in the southwest corner of the on-Site building where the source of nitrates, VOCs, and PFAS was identified. While sub-slab depressurization fans have been installed,
no indoor air data has been collected to indicate Site receptors are protected from the potentially complete inhalation pathway. Additionally, COPCs may be flowing into Millcreek resulting
in a potentially completed exposure pathway for aquatic organisms. All potentially complete exposure pathways are required to be evaluated prior to closure determination.
The Division understands the data quality objective (DQO)for the Site is to obtain a corrective action complete with controls determination. The Division agrees with the Report’s proposed
excavation of source soils and installation of additional monitoring wells downgradient to the south and southwest of the Site. Additionally, indoor air and the potential impact to Millcreek
should be investigatedfor human and ecological receptors.
The data presented in the Report indicates that additional investigation measures and corrective action should be carried out. Please prepare an additional investigation work plan by
December 31, 2024. The Division has no comments or questions concerning this Report. The Report is hereby approved.If you have any questions, please call Ethan Uptonat [phone].
Sincerely,
Douglas J. Hansen, Director
Division of Waste Management and Radiation Control
DJH/EAU
c:Dorothy Adams, Interim Health Officer, Salt Lake County Health Dept.
Ron Lund, Environmental Health Director, Salt Lake County Health Dept.
Eric Peterson, Environmental Health Deputy Director, Salt Lake County Health Dept.
Blake Downey, Wasatch Environmental, Inc. [e-mail]