DSHW-2023-207959 - 0901a06881258663

State of Utah Mail - Opus Green - Soil Stockpile Characterization and Disposal and Soil Confirmation Sampling WP
Deq submit <[e-mail]>
Opus Green - Soil Stockpile Characterization and Disposal and Soil Confirmation
Sampling WP
1 message
Blake Downey <[e-mail]>Mon, Aug 14, 2023 at 9:15 AM
To: "[e-mail]" <[e-mail]>, Heather Mickelson <[e-mail]>, "[e-mail]"
<[e-mail]>
Cc: Micah Peters <[e-mail]>, Steve Bull <[e-mail]>
Heather,
Please see the attached work plan to complete soil stockpile characterization activities to facilitate the proper disposal of
the soil, and soil confirmation sampling for the Opus Green Facility as discussed previously. Please let me know if you
have any comments.
Thank you!
Blake Downey, P.G.
Senior Project Hydrogeologist
Wasatch Environmental
2410 West California Avenue
Salt Lake City, Utah 84104
Cell:
Office: 801-972-8400
Email: [e-mail]
Soil Stockpile Charaterization-Disposal and Soil Confrimation Sampling WP.pdf
1052K
DSHW-2023-207959

WASATCH ENVIRONMENTAL, INC.
ENVIRONMENTAL SCIENCE AND ENGINEERING

2410 WEST CALIFORNIA AVENUE
SALT LAKE CITY, UTAH 84104
PHONE [phone]
FAX [phone]
e-mail: [e-mail]
www.wasatch-environmental.com

WORK PLAN FOR SOIL STOCKPILE SAMPLING AND DISPOSAL
AND SOIL CONFIRMATION SAMPLING
OPUS GREEN TOWNHOMES
APPROXIMATLEY 4196 SOUTH MAIN STREET
MILLCREEK, UTAH

PROJECT NO. 2242-004E

PREPARED FOR:

MR. DOUG HANSEN
UTAH DEPARTMENT OF ENVIRONMENTAL QUALITY
DIVISION OF WASTE MANAGEMENT AND RADIATION CONTROL
195 NORTH 1950 WEST, 2ND FLOOR
P.O. BOX 144880
SALT LAKE CITY, UTAH 84114-4880

PREPARED BY:

WASATCH ENVIRONMENTAL, INC.
2410 WEST CALIFORNIA AVE
SALT LAKE CITY, UTAH 84104
801-972-8400
FAX: [phone]

AUGUST 14, 2023
Work Plan for Soil Stockpiling Sampling Opus Green Townhomes
and Disposal and Soil Confirmation Sampling Project No. 2242-004E
Wasatch Environmental, Inc. Page i

TABLE OF CONTENTS

Section Page No.
1. INTRODUCTION .............................................................................................................................. 1
2. FACILITY BACKGROUND............................................................................................................... 1
3. OBJECTIVES ................................................................................................................................... 3
4. SAMPLING METHODOLOGY ......................................................................................................... 4
4.1 Composite Soil Sampling and Impacted Soil Disposal ....................................................... 4
5. CONTINGENCY ACTIVITIES .......................................................................................................... 4
6. REPORTING .................................................................................................................................... 4

FIGURE

Figure 1 – Proposed Sample Location Map

Work Plan for Soil Stockpiling Sampling Opus Green Townhomes
and Disposal and Soil Confirmation Sampling Project No. 2242-004E
Wasatch Environmental, Inc. Page 1

WORK PLAN FOR SOIL STOCKPILE SAMPLING AND DISPOSABLE
AND SOIL CONFIRMATION SAMPLING
OPUS GREEN TOWNHOMES
APPROXIMATLEY 4196 SOUTH MAIN STREET
MILLCREEK, UTAH

1. INTRODUCTION

In accordance with the Utah Division of Waste Management and Radiation Control (DWMRC) request,
Wasatch Environmental, Inc., (Wasatch) has prepared this work plan for completing heavy metal-
impacted soil stockpile sampling and disposal and soil confirmations sampling at the Opus Green
Townhomes property located at approximately 4196 South Main Street in Millcreek, Utah (Facility). This
work would include the collection of one composite soil sample of the heavy metal-impacted soil stockpile
and six composite soil confirmation samples.

The objective of this work is to properly characterized and dispose of a heavy metal-impacted soil
stockpile, and verify that the areas where the heavy metals-impacted soils were handled are not impacted
and if so, that those impacts are remediated.

2. FACILITY BACKGROUND

The Facility is an approximately 7.05-acre tract of real property, further identified as Salt Lake County tax
parcel number: 21-01-228-015-0000. At the time of this work plan, the Facility is vacant land under
residential construction (as shown in Exhibit A). The legal description of the Facility is:

Beginning North at 87°01'34" East 16.16 feet and North 0°15'54" East 1741.07 feet and North 76°16'11"
West 33.93 feet from East 1/4 Corner of Section 1, Township 2S, Range 1W, S L M; North 76°16'11"
West 23.32 feet; North 40°00'30" West 154.8 feet; North 68°26'54" West 290.8 feet; North 76°57'23"
West 457 feet; South 29°13'33" West 51.05 feet; North 8°59' West 359.4 feet; South 89°14'45" East
748.55 feet M OR L; South 3°50' West 368.14 feet; North 85°15' East 197.01 feet; South 0°15'54" West
283.64 feet to beginning. Contains 7.05 acre.

The Facility is known to be located in an area of former historical ore smelters from approximately 1874 to
1899. Wasatch has direct knowledge of environmental impacts identified on adjacent redeveloped
properties. The main environmental impacts identified on the adjacent properties are the heavy metals
lead and arsenic.

Phase I and Phase II Environmental Site Assessments

Wasatch completed a Phase I Environmental Site Assessment (ESA) for the Facility dated April 5, 2019,
on behalf of Clearwater Homes Utah. The Phase I ESA identified the following recognized environmental
conditions:

• Between at least the 1970s and 1980s, there were two large aboveground storage tanks (ASTs)
on the Facility. Given past uses of the Facility, there is a potential that these ASTs contained fuel
or oil and releases may have impacted the Facility.

• The Facility was historically a slag dump for a smelter. Analytical results for a soil sample
collected from the Facility in 1993, and analytical results for a slag sample collected by Wasatch
indicate elevated concentrations of lead and arsenic. Additionally, samples of native soil
collected from the adjoining east property also indicate elevated concentrations of metals likely
Work Plan for Soil Stockpiling Sampling Opus Green Townhomes
and Disposal and Soil Confirmation Sampling Project No. 2242-004E
Wasatch Environmental, Inc. Page 2
attributed to smelter aerial deposition.

• Concentrations of lead in soil samples collected from the fill material on the adjoining east
property exceed United States Environmental Protection Agency (U.S. EPA) Regional Screening
Levels (RSLs) for Industrial Soil. The on-site fill material originated from the former ore smelters.
Therefore, there is a potential for elevated concentrations of lead in the fill material on the Facility.

Given the identified recognized environmental conditions, Wasatch directed the completion of seven soil
borings at the Facility to evaluate the degree of soil and groundwater impacts present at the Facility by
contaminants previously identified at and near the Facility.

On April 6, 2018, Wasatch directed the completion of seven soil borings (GP-1 through GP-7), using
direct-push drilling techniques, to evaluate soil and groundwater conditions at the Facility. The boring
locations are shown in Exhibit A.

One soil and one groundwater sample were collected from each boring and analyzed for volatile organic
compounds (VOCs), semi-volatile organic compounds (SVOCs), and Resource Conservation and
Recovery Act (RCRA) D-list metals.

Based on the observed lithology of the soil borings, on-site fill material is approximately 9 to 12 feet in
thickness and consists mainly of gravelly sand, sand, and some silt with red brick debris, concrete debris,
glass debris, slag, plastic debris, tar-like material, and wood debris. Depth to groundwater ranged
between approximately 7.5 to 19 feet below ground surface (bgs), with an average depth of 10.79 feet.
Slight petroleum odors were observed in soil boring GP-4 at a depth of 9 feet. Photoionization detector
(PID) readings ranged from 0.0 to 12.2 parts per million (ppm).

Based on extensive geotechnical soil borings/test pits and Wasatch’s soil borings, the observed slag
appears to be predominantly located at depths in the fill material between 3 and 10 feet.

The soil sample collected from soil boring GP-4 exhibited detectable concentrations of petroleum
hydrocarbon constituents and a slight petroleum odor. The petroleum hydrocarbon concentrations were
below the applicable U.S. EPA RSLs for Residential Soil; however, they indicate that a release of
petroleum product has occurred. Additionally, this boring was located approximately 40 feet west of
where the former ASTs (the suspected release point) were located.

The shallow soil samples (ranging from 1 to 4 feet bgs) collected from each soil boring exhibited arsenic
concentrations that exceeded the applicable U.S. EPA RSL for Residential Soil for arsenic of 0.68
milligrams per kilogram (mg/kg). However, site-specific background arsenic in soil concentrations were
developed for the Facility, and it was determined that the detected arsenic concentrations are considered
to be within the typical background concentration for this area.

Two deep soil samples were collected from the fill/native soil interface where the majority of the slag was
observed. These samples (GP-3-9’ and GP-4-9.5’) exhibited lead and arsenic concentrations in excess
of their applicable U.S. EPA RSL for Residential Soil. Soil sample GP-3-9’ exhibited and arsenic and lead
concentrations of 145 mg/kg and 3,850 mg/kg, respectively. Soil sample GP-4-9.5’ exhibited arsenic and
lead concentrations of 106 mg/kg and 2,160 mg/kg, respectively.

Soil sample GP-7-2’ exhibited a benzo(a)pyrene (BAP) concentration of 1,710 micrograms per kilogram
(µg/kg). This concentration exceeds the U.S. EPA RSL for Residential Soil of 110 µg/kg. No other
SVOCs were detected at concentrations above U.S. EPA RSLs for Residential Soil.

No SVOCs, VOCs, RCRA D-list metals (except for arsenic) were detected at concentrations in
groundwater that exceed applicable U.S. EPA Maximum Contaminant Levels (MCLs).

All groundwater samples except GP-7 exhibited arsenic concentrations that exceed the applicable U.S.
EPA MCL for arsenic of 0.01 milligrams per liter (mg/L).
Work Plan for Soil Stockpiling Sampling Opus Green Townhomes
and Disposal and Soil Confirmation Sampling Project No. 2242-004E
Wasatch Environmental, Inc. Page 3
Division of Waste Management and Radiation (DWMRC) Oversight

DWMRC oversight was requested in December 2021. At the request of the Utah DWMRC, Wasatch
completed a human health risk assessment (HHRA), ecological risk assessment (ERA [which included
the northern bank of the adjoining south Big Cottonwood Creek]), and a background arsenic evaluation.
The work plan for this effort was approved by DWMRC in a letter dated May 24, 2022. Since August
2019, Wasatch has completed 29 additional test pits across the Facility to further evaluate the on-site
impacts.

Since the collection of the GP-4-9.5’ soil sample, which exhibited petroleum hydrocarbon impacts at
concentrations below their applicable U.S. EPA RSLs for Residential Soil, Wasatch has completed six
additional test pits in this area and the area of the former AST(s). No SVOCs, VOCs, or lead were
detected in the soil samples collected from the step-out test pits at concentrations that exceed their
applicable U.S. EPA RSLs for Residential Soil.

Since the collection of the GP-7-2’ soil sample, which exhibited a BAP concentration that slightly
exceeded the applicable U.S. EPA RSL for Residential Soil, Wasatch completed five additional test pits in
this area. No PAHs (including BAP) were detected in the soil samples collected from the step-out test pits
at concentrations that exceed their applicable U.S. EPA RSLs for Residential Soil.

Based on the calculated site-specific background arsenic evaluation and research of arsenic
concentrations in soil for nearby sites, the arsenic impacts to soil at the Facility are considered to be
within the typical background concentration for this area.

Since the collection of the GP-3-9’ soil sample, which exhibited a lead concentration that exceeded the
applicable U.S. EPA RSL for Residential Soil, Wasatch completed four additional step-out test pits in this
area. No lead was detected in the soil samples collected from the step-out test pits at concentrations that
exceed the applicable U.S. EPA RSL for Residential Soil.

Since the collection of the GP-4-9.5’ soil sample, which exhibited a lead concentration that exceeded the
applicable U.S. EPA RSL for Residential Soil, Wasatch completed four additional step-out test pits in this
area. No lead was detected in the soil samples collected from the step-out test pits at concentrations that
exceed the applicable U.S. EPA RSL for Residential Soil.

A Site Management Plan (SMP) and Environmental Covenant (EC) has been completed for the Facility,
approved by DWRMC, and recorded with the Salt Lake County Recorders office. These documents
supported the regulatory closure of the Facility and documented the required institutional and engineering
controls to be maintained at the Facility. A DWMRC letter dated June 8, 2023, documented that a
DWMRC representative conducted a site visit of the Facility to confirm that Activity and Use Limitations
were being followed. The representative observed that excavations deeper than 3 feet bgs were present
and DWMRC had not been notified of these excavations, per the requirements in the SMP. Additionally,
potential slag material was observed.

In response to the DWMRC letter, Wasatch was retained to inspect the Facility and complete a Site walk
with DWMRC to discuss what excavations had taken place at the Facility, where soil was handled, and
where potential heavy metal-impacted soil had been stockpiled. On July 27, 2023, Wasatch completed a
Facility walk with DWMRC personnel to discuss those issues and determine a path forward to properly
characterize and dispose of the suspected heavy metal-impacted stockpiled soil. Additionally, a
confirmation soil sampling plan was discussed.

3. OBJECTIVES

The objectives of this work are as follows:

• Properly characterize the heavy metal-impacted soil stockpile.
Work Plan for Soil Stockpiling Sampling Opus Green Townhomes
and Disposal and Soil Confirmation Sampling Project No. 2242-004E
Wasatch Environmental, Inc. Page 4

• Properly dispose of the heavy metal-impacted soil stockpile.

• Collect composite soil samples in the areas where heavy metal-impacted soil was handled and
stockpiled.

• Properly document all field activities completed at the Facility.

4. SAMPLING METHODOLOGY

4.1 Composite Soil Sampling and Impacted Soil Disposal

One twenty-point composite sample will be collected from the heavy metal-impacted soil stockpile located
at the Facility to facilitate the proper characterization of the waste for disposal purposes.

Six twenty-point composite surface soil confirmation samples (collected from the top 3-inches of soil) will
be collected from six areas, each representing their own decision unit (DU), where the heavy metal-
impacted soil was handled and/or stockpiled. These samples will be collected to evaluate if surface soil
at the Facility may need to be remediated. See Figure 1 for the general locations of the soil stockpile and
confirmation soil sample/DU areas. Each aliquot location would be randomly selected to provide
sufficient spatial distribution.

Each aliquot for the 20-point composite stockpile/surface soil samples would be collected using gloved
hands and a clean 4-ounce glass jar. A new 4-ounce glass jar would be used for each DU. Each aliquot
would consist of 2-ounces of soil. For each DU, the aliquots would be placed inside a plastic Zip Lock
bag and homogenized for a minimum of 5 minutes prior to dispensing the soil into the laboratory
supplied/prepared sample containers.

All soil samples would be transported under chain-of-custody, in an iced cooler to Chemtech-Ford
Laboratories (CF) for analysis of lead and arsenic using U.S. EPA Method 6020B or A. Additionally, the
soil stockpile sample will be analyzed for the required analytes of the disposal facility. At a minimum, that
would include Toxic Characteristic Leaching Procedure (TCLP) for RCRA D-list metals. Wasatch
anticipates that this waste will either be disposed of at the Salt Lake County Landfill or at Intermountain
Regional Landfill.

The laboratory will use level 3 quality assurance/quality control (QA/QC) reporting for all soil samples.

5. CONTINGENCY ACTIVITIES

If surface soil confirmation samples indicate that lead impacts exceed the U.S. EPA RSL for Residential
Soil (400 mg/kg) or that arsenic impacts exceeds the DWMRC-approved site-specific background value of
69.35 mg/kg, the surface soil within that DU will be excavated and disposed of at the same facility as the
heavy metal-impacted soil stockpile. Excavation will be completed until surface soil composite samples
exhibit lead and arsenic concentrations below the above stated screening levels, or until the excavation
reaches a depth of 3 feet bgs. Surface soil confirmation samples would be collected as described in
Section 4. Each area where heavy metal impacted soils were handled will eventually be constructed with
a slab-on-grade apartment complex.

6. REPORTING

All data generated during the sampling will be documented in a final report. This report will include the
following:
Work Plan for Soil Stockpiling Sampling Opus Green Townhomes
and Disposal and Soil Confirmation Sampling Project No. 2242-004E
Wasatch Environmental, Inc. Page 5
• Text,

• Applicable tables,

• Maps,

• Chain of custody forms,

• Laboratory analytical results,

• Waste disposal documentation, and

• Conclusions and recommendations.

The results of the sampling and analysis will be summarized in the report. Data will be presented in table
format. Conclusions based on the data as well as field observations will be included in the report. After
the laboratory data has been received, and reviewed, the report will be completed and submitted to the
Client prior to submission to DWMRC.

Sincerely,

WASATCH ENVIRONMENTAL, INC.

Blake Downey, P.G.
Senior Project Hydrogeologist

Distribution: (1) Hard Copy - Addressee
(1) Electronic – Micah Peters, Clearwater Homes

Figure

FIGUREDATE: 8-7-23PROJECT NO.: 2242-004EEnvironmental Science and Engineering
Proposed Soil Confirmation Sample Location Map
Opus Green Townhomes
4186 South Main Street
Millcreek, Utah
Scale: 1-inch equals
approximately 110’
1
Approximate
Location of
Facility
Ma
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LEGEND
Composite Soil Sample Decision Unit
Impacted Soil Stockpile
DU
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1
DU-3DU-2
DU-5DU-4
DU-6
DU-1