140A1119Q0021_Solicitation_without_SF-1449.pdf

BIA Western Regional Office Sol. No. 140A1119Q0021

CONTENTS

1. SECTION B SUPPLIES OR SERVICES AND PRICES

QUOTE SCHEDULE

2. SECTION C DESCRIPTION / SPECIFICATIONS

Specification / Statement of Work / Performance Work Statement

3. SECTION F DELIVERIES OR PERFORMANCE

1452.280-3 Subcontracting limitations July 2013 (Deviation) 52.219-14 Limitations on Subcontracting January 2017 52.242-15 Stop-Work Order August 1989

4. SECTION G CONTRACT ADMINISTRATION DATA

DOI Electronic Invoicing and Payment Requirements – Invoice Processing Platform (IPP) April 2013

5. SECTION H SPECIAL CONTRACT REQUIREMENTS

No Text Messaging While Driving (policy) Tribal Taxes, Requirements and /or Restrictions Core Working Hours: Days of Work / Hours of Work

6. SECTION I CONTRACT CLAUSES

1452.226-70 Indian Preference. —Department of the Interior April 1984 (Deviation) 1452.226-71 Indian Preference Program— Department of the Interior April 1984 (Deviation) 1452.280-2 Notice of Indian Economic Enterprise Set-Aside July 2013 (Deviation) 1452.280-3 Subcontracting Limitations July 2013 (Deviation 52.203-16 Preventing Personal Conflicts of Interest December 2011 52.204-4 Printed or Copied Double-Sided on Postconsumer

Fiber Content Paper May 2011 52.204-10 Reporting Executive Compensation and First-Tier

Subcontract Awards October 2016 52.204-13 System for Award Management Maintenance October 2016 52.212-4 Contract Terms and Conditions -- Commercial Items October 2018 52.212-5 Contract Terms and Conditions Required to Implement Statutes or Executive Orders -- Commercial Items January 2019 52.217-8 Option to Extend Services November 1999 52.223-3 Hazardous Material Identification and Material Safety Data January 1997

52.223-5 Pollution Prevention and Right-to-Know Information May 2011 52.223-18 Encouraging Contractor Policies to Ban Text Messaging

While Driving August 2011 52.228-5 Insurance—Work on a Government Installation January 1997 52.229-3 Federal, State and Local Taxes February 2013

52.232-1 Payments April 1984 52.232-8 Discounts for Prompt Payment February 2002 52.232-11 Extras April 1984 52.232-25 Prompt Payment January 2017 52.232-39 Unenforceability of Unauthorized Obligations January 2013 52.232-40 Providing Accelerated Payments to Small Business

Subcontractors December 2013 52.233-3 Protest after Award August 1996 52.236-7 Permits and Responsibilities November 1991 javascript:__doPostBack('ctl00$ctl00$body$homebody$RecentDocuments$C$RecentDocumentsControl$RecentDocumentResults$ctl00$DocumentNumberLink','')

52.237-1 Site Visit April 1984 52.237-2 Protection of Government Buildings, Equipment, and Vegetation April 1984 52.237-3 Continuity of Services January 1991

52.203-99 Prohibition on Contracting with Entities that Require Certain February 2015 Confidentiality Agreements (DEVIATION 2015-02)

52.252-2 Clauses Incorporated by Reference February 1998

7. SECTION J LIST OF DOCUMENTS, EXHIBITS, AND OTHER ATTACHMENTS

By Reference - Applicable Service Contract Act (SCA) Wage Determination No. WD 15-5469 DOI Policy - Prohibition on Texting While Driving

8. SECTION K REPRESENTATIONS, CERTIFICATIONS, AND OTHER STATEMENTS OF BIDDERS

Level of Effort - Prime & Subcontractor service effort 1452.280-4 Indian Economic Enterprise Representation July 2013 (Deviation) 1452.280-2 Notice of Indian Economic Enterprise Set-Aside July 2013 (Deviation)

52.203-98 Prohibition on Contracting with Entities that Require Certain Internal Confidentiality Agreements—Representation February 2015 (Deviation 2015-02)

52.203-18 Prohibition on Contracting with Entities that Require Certain Internal Confidentiality Agreements or Statements-Representation January 2017

52.204-17 Ownership or Control of Offeror July 2016 52.204-19 Incorporation by Reference of Representations and Certifications December 2014 52.204-20 Predecessor of Offeror July 2016 52.209-2 Prohibition on Contracting with Inverted Domestic Corporations—

Representation November 2015 52.209-7 Information Regarding Responsibility Matters July 2013 52.209-11 Representation by Corporations Regarding Delinquent Tax Liability or a Felony Conviction under any Federal Law February 2016 52.209-12 Certification Regarding Tax Matters February 2016 52.212-3 Offeror Representations and Certifications -- Commercial Items October 2018 52.225-25 Prohibition on Contracting with Entities Engaging in Certain Activities or Transactions Relating to Iran—Representation and Certifications October 2015

9. SECTION L INSTRUCTIONS, CONDITIONS, AND NOTICES TO BIDDERS

1452.280-1 Notice of Indian Small Business Economic Enterprise Set-Aside July 2013 (Deviation) Quote completion & submission Instructions 1452.233-2 Service of Protest Department of the Interior July 1996 (Deviation) 52.204-6 Unique Entity Identifier July 2013 52.204-7 System for Award Management October 2016 52.204-16 Commercial and Government Entity Code Reporting July 2016 52.204-18 Commercial and Government Entity Code Maintenance July 2016 52.212-1 Instructions to Offerors -- Commercial Items January 2017 52.233-2 Service of Protest September 2006

10. SECTION M EVALUATION FACTORS FOR AWARD

General 52.212-2 Evaluation—Commercial Items October 2014 javascript:__doPostBack('ctl00$ctl00$body$homebody$RecentDocuments$C$RecentDocumentsControl$RecentDocumentResults$ctl00$DocumentNumberLink','')

SECTION B SUPPLIES OR SERVICES AND PRICES

1452.280-1 Notice of Indian Small Business Economic Enterprise Set-Aside July 2013 (Deviation)

Under the Buy Indian Act, 25 U.S.C. 47, offers are solicited only from Indian economic enterprises (Subpart 1480.8) that are also small business concerns. Any acquisition resulting from this solicitation will be from such a concern. Offers received from enterprises that are not both Indian economic enterprises and small business concerns will not be considered and will be rejected.

THIS PROCUREMENT IS A 100% INDIAN SMALL BUSINESS ECONOMIC ENTERPRISE SET ASIDE, issued under NAICS Code 562910 with a $750-employee Small Business Size Standard.

Applicable Service Contract Act Wage Determination No.: 15-5469, Rev. No. 9, 12/26/2018

Additional Service Contract Labor Standards will be issued for work outside of Pinal County.

CONTRACTOR________________________________________ DUNS#________________________________

PHONE # ___________________________________ EMAIL ADDRESS____________________________________

QUOTE SCHEDULE

The quote amount is to be inclusive of all costs to complete the requirement, including but not limited to, all applicable taxes (Federal, State & Tribal), all labor and supervision, equipment, material & supplies, permits, etc.

SECTION C DESCRIPTION / SPECIFICATIONS

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SCIP PCB Supplemental Site Investigation

Table of Contents

1.0 Introduction

2.0 Site Description

2.1 Current Conditions

2.2 Site Characteristics

2.3 Summary of Previous Investigations

3.0 Human Health Risk Evaluation

3.1 Data Evaluation

3.2 Human Health Conceptual Site Model

3.3 Human Health Exposure Areas

3.4 Risk Characterization

4.0 Statement of Work

4.1 Additional On/Off Site Sampling/Assessment of Contamination

4.2 Soil Sampling Locations

4.3 Groundwater Sampling

4.4 Analytical Requirements

4.5 Investigation-derived wastes

4.6 Decontamination

4.7 Additional Planning Documents

4.8 Deliverables

5.0 Project Management

5.1 Project Schedule

5.2 Project Personnel

6.0 List of Attachments

7.0 Period of Performance

8.0 Place of Performance

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1.0 INTRODUCTION

The BIA San Carlos Irrigation Project (SCIP) Maintenance Yard (the “Yard”) located approximately 2 miles north of downtown Coolidge, AZ, at the junction of Arizona highways 87 and 287 (shown in Figure 1).

The Site is approximately 20 acres; it functions as SCIP’s primary electrical power and irrigation water distribution facility, and fuel storage and dispensing operations and maintenance yard for storage and repair of SCIP’s fleet of vehicles, trucks, and industrial equipment. In addition, electrical transformers are stored, tested, and maintained at the Yard. Before the practice was prohibited in the late 1970s, BIA personnel applied spent transformer oil as a dust palliative to unpaved ground surfaces in parking and other high‐traffic areas throughout the 20‐acre yard for a span of over 40 years. This practice led to the presence of polychlorinated biphenyl (PCB) compounds in the surface and shallow subsurface soil at the Yard and several adjacent offsite properties.

This project shall be conducted under the PCB regulations in the Toxic Substances Control Act (TSCA). A human health risk‐based approach was used to determine current and potential future risks using available data as well as data needs. The methodology presented in the 2017 USEPA regional screening levels (RSLs) (www.epa.gov/risk/regional‐ screening‐levels‐rsls) aided development of risk‐based screening levels and human‐health risk estimates.

The project Work Plan describes the sampling and analysis of PCBs and total petroleum hydrocarbons to be implemented at the Yard and adjacent area (Site) to complete an extent investigation and supply sufficient information to develop a remediation strategy.

2.0 SITE DESCRIPTION

The 20‐acre SCIP Maintenance Yard and adjoining project offices are located at 13805 N. Arizona Boulevard in Coolidge, AZ, approximately 2 miles north of downtown at the junction of Arizona highways 87 and 287 (see Figure 1).

Approximately one third of the Yard is paved. An electrical substation is located inside a graveled, fenced area near the center of the maintenance yard. The remainder of the Yard is used for equipment storage in several buildings and outdoor storage areas. Figure 2 shows the Site’s layout and features.

2.1 Current Conditions

Current SCIP operations include administering and metering power and irrigation water distribution utilities, storage and service of new and antiquated electrical transformers (e.g., pole‐mounted and larger substation transformers), fuel storage and fueling operations, and parking and maintenance of vehicles and heavy‐duty power and irrigation equipment. At present, SCIP does not generate electricity, but transmits and distributes purchased power, and provides irrigation water for agricultural customers throughout south‐central Arizona.

PCBs are known to exist currently at concentrations above human‐health risk‐based screening levels in soils at and around the perimeter of the Yard, based on previously collected soil samples. Total petroleum hydrocarbons (TPH) impacts have been found at several areas at the Site (E W Wells Group, 2017).

2.1.1 Surrounding Land Use

Land use around the Site is generally agricultural. The SCIP Maintenance Yard, which is BIA‐owned property, is Parcel Number 209‐10‐0110. Figure 3 shows the perimeter properties of the Site. These adjacent properties include the following:

1) Union Pacific Railroad Parcel East, a portion of which is identified as Perimeter Area–East, is directly east of the SCIP Maintenance Yard and is a right‐of‐way for the rail line (Parcel Number 209‐10‐0200).

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2) State of Arizona Parcel South, portions of which are identified as Perimeter Area–Southwest and Perimeter Area–South, is owned by the state (Parcel Number 209‐10‐0160). The southern part of the property is used as the right‐ of‐way for Highway 287.

3) MLC Family Trust Parcel, a portion of which is identified as Perimeter Area– North, is owned by MLC Farms LLC (Parcel Number 209‐10‐0070).

4) The BIA owns the parcels to the west of the maintenance yard (Parcel Numbers 209‐10‐010A and 10B).

2.1.2 Principal Stakeholders

The primary stakeholders on the project are associated with the owners of the Site and the surrounding land owners as follows:

1) Bureau of Indian Affairs (owner of Yard)

2) San Carlos Irrigation Project (operator of Yard)

3) Arizona Department of Transportation (ADOT) (operator of state‐owned parcel south of Site:

Perimeter Area–Southwest and Perimeter Area–South)

4) Union Pacific Railroad (owner/operator of parcel east of Site: Perimeter Area–East)

5) MLC Farms LLC (owner of parcel north of Site: Perimeter Area–North).

2.2 Site Overview

2.2.1 Site History and Cultural Survey

The SCIP Maintenance Yard and adjacent properties are located within the National Registry of Historic Places (NRHP)‐eligible prehistoric archaeological site known as the Grewe Site. The Grewe Site has been previously excavated outside of the SCIP yard and is known to contain buried artifacts and features such as canals, pit houses, and burials. The Grewe Site is culturally sensitive and several tribes consider it a traditional cultural property. Additionally, the SCIP yard’s historic structures were previously determined eligible for listing on the NRHP.

During previous investigations, the Arizona State Historic Preservation Office (SHPO) has concurred with PCB investigation studies at SCIP that: (1) are not conducted within any structures; (2) do not alter the design, layout, or functionality of the facility and therefore do not affect the historic component of the SCIP yard; and

(3) use a two‐inch diameter soil probe to characterize the soil at a depth not to exceed 24 inches.

The SHPO concurred that the limited area of the maintenance yard and shallow depth of soil testing were not expected to adversely affect the Grewe Site. Coordination with Arizona SHPO for sampling activities is not expected to be necessary as long as sampling is limited to comply with the preceding three factors.

Because the SCIP Maintenance Yard and adjacent properties are located within an NRHP‐eligible archaeological site, any ground disturbance in this area can potentially affect cultural resources. Harris Environmental recommended (2017) that the project proponents work closely with the Arizona SHPO and tribal representatives to identify a remediation plan that is appropriate for this sensitive area.

2.2.2 Topography

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The Site is within the Gila River Watershed. The Gila River bed lies approximately 4,000 feet north of the Site (Figure 1). The river has seasonal flow during and after rain events. Flow in this area is from the east to west.

The Gila River flows into the Colorado River in Yuma, AZ.

Site topography is generally flat with a low slope to the north. The relatively flat topography has a 4‐foot elevation decrease from the south to the north of the Site. As a result, stormwater runoff in the SCIP yard drains toward the north.

2.2.3 Hydrogeology and Hydrology

The SCIP’s facilities yard is located in the Eloy groundwater sub‐basin in the Pinal active management area (AMA) near several irrigation districts that use groundwater and surface water for irrigation. The groundwater conditions have been heavily influenced by extensive irrigation practices over the years, resulting in large water‐level declines and rises in several areas.

Based on regional groundwater studies of the Pinal AMA and the Eloy sub‐basin, generally two primary water‐bearing zones occur near the SCIP area. A lower aquifer system exists primarily in the lower basin fill with a depth‐to‐water that ranges from about 200 feet below ground surface (bgs) southeast of Coolidge to over 500 feet bgs farther south (Hammet 1992). A fine‐grained middle unit is located above this layer in much of the Eloy sub‐basin, which confines the lower aquifer in several areas.

The upper aquifer system is contained mostly in the upper basin and more recent alluvium along streams and rivers. It is located above the middle fine‐grained layer and is generally unconfined in the SCIP area. It is considered to be the Eloy sub‐basin’s primary groundwater production zone. Transmissivity values for the upper aquifer system near Coolidge range between 12,000 feet2/day and 20,000 feet2/day (Pool et al., 2001).

Based on data in the Arizona Department of Water Resources (ADWR) well registry; the upper aquifer system’s depth‐to‐water near SCIP ranges from about 150 to 300 feet bgs. Prior to groundwater development, the regional groundwater flow direction in the upper aquifer was toward the north‐northwest.

Post‐development, groundwater in the upper aquifer flows southwest toward a groundwater trough located midway between the recharge areas of the Casa Grande Mountains and the Gila River. Flow in the lower aquifer system is southwest toward the west edge of the basin (Pool et al., 2001). However, production from irrigation, industrial and municipal supply wells will locally control the groundwater flow direction. Local perched groundwater occurs in the sub‐basin and may exist in the Coolidge area.

The ADWR well database (i.e., Well 55 Registry and GSWI) reports two wells are present at the SCIP facility, one installed in January 1960 and the other at an unknown date but prior to June 1968; their depths are 796 and 515 feet respectively. The well database lists only an approximate location for both wells, based on the public land survey system quarter–quarter section, indicating the 40‐acre general area.

The ADWR well database indicates that Southwest Gas Corporation (SWGC) drilled an exploratory boring to 230 feet in November 1993 and installed a cathodic protection well on the quarter–quarter–quarter section southwest of the BIA property. The center of the 10‐acre area is shown as an approximate location on Figure 2, even though the well could not be found in the field. The well was installed to a depth of 230 feet. The well drillers’ report form indicated the depth‐to‐water was not applicable, denoted by a dash. Although not definitive, this suggests groundwater was not encountered in significant quantities in the 230 feet drilled. The well log submitted indicates top soil from 0 to 7 feet bgs, clay from 7 to 16 feet, alluvial gravel from 17 to 102 feet, and clay from 102 to 230 feet. The boring was filled with coke and the upper 20 feet was filled with concrete. The 1.5‐inch diameter PVC vent pipe is offset from the well boring at a depth of at least 3 feet and capped with concrete with a roadway valve box. The completion offset makes it impossible to attempt to sample or measure a water level in the vent pipe.

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Two water wells are located on the property in this area (shown on Figure 2). One of the wells is in the southcentral area of the maintenance yard, approximately 10 feet east of the substation. The second well is capped by a metal plate and located inside the substation, approximately 80 feet southeast of the first well.

When the plate was removed, this well appeared to have collapsed to a depth of 20 feet bgs. The first well is out of service but still has a pump installed. It is likely but not known if these are the two wells described in the ADWR database and, if so, which well is deeper. The ADWR database indicates that, when in operation, the capacity of each pump was 150 gallons per minute (gpm). Both wells had a depth‐to‐water of about 150 feet, recorded in 1982. No recent data on depth‐to‐water near the SCIP yard was found. Based on the available data of other wells in the area, the depth‐to‐water is assumed to range from 150 to 300 feet. The pumping capacity of other wells in the area ranges from 30 gpm for domestic wells to 1,500 gpm for commercial, irrigation and industrial wells.

The Site topography is relatively flat and exhibits a 4‐foot elevation decrease from the south to the north of the Site. This slight slope results in storm water runoff in the SCIP yard that drains northward. The Gila River is located approximately 4,000 feet north of the Site and the water flows from east to west. The area has a series of drainage ditches and culverts.

Historical natural drainage channels in the area have been modified since the early 1900s into irrigation canals for farming (Klawon et al., 1998). Until recently, a canal located north of the maintenance yard and immediately west of the Union Pacific rail line drained to the south, turned west at the north boundary of the Site, and then turned south and water flowed through the SCIP facility immediately west of the yard. Along the north side of the maintenance yard, the canal’s southern levee caused Site runoff to pool in the area north of the fence line (in Perimeter Area–North). In fall 2017, this canal was replaced with a buried pipeline.

An infiltration‐evaporation pond onsite is located west of the transformer substation and south of the office parking lot and receives parking lot runoff. BIA has indicated that a large north–south trending storm water culvert was buried in this area when the infiltration pond was installed.

2.2.4 Biological Survey

A preliminary ecological reconnaissance was completed in 2017 and the Biological Report was prepared. The project limits, for the most part, are developed with some landscaped plants (e.g., palm trees, cypress), and creosote and desert broom occupy previously disturbed areas. Undeveloped, natural areas, such as the land surrounding the protected Case Grande Ruins, consist of creosote interspersed with velvet mesquite and saltbush. Most of the land surrounding the SCIP yard comprises actively managed agricultural fields.

Under contract with BIA, Harris Environmental Services (Harris) queried the United States Fish and Wildlife Service (USFWS) Information, Planning, and Conservation (IPaC) system to obtain a list of threatened, endangered, proposed, and candidate flora and fauna species, and designated and proposed critical habitat that are within one 7.5‐ minute quadrangle of the project area.

Harris identified a total of three (3) federally protected species were listed in the USFWS IPaC query. Two of these species have proposed critical habitat; however, no proposed critical habitat exists inside the project limits. In April 2017, the USFWS withdrew the proposed rule to list the round‐tail chub (Gila robusta) as a federally threatened species. This species has been removed from the federally protected species list and was not reviewed in the Biological Report

The Arizona Game and Fish Department’s (AGFD) Heritage Data Management System (HDMS) was queried to determine (1) whether any special status species have been documented in close proximity (i.e., 5 miles) to the project limits; or (2) whether any species of greatest conservation need (SGCN), based on predicted range models, are within the project vicinity. Based on this review, the following species should be further investigated prior to remediation activities:

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• Tucson Shovel‐Nosed Snake (Chionactis occipitalis klauberi)

• Sonoran Desert Tortoise (Gopherus morafkai)

• Gila Monster (Heloderma suspectum)

• Western Burrowing Owl (Athene cunicularia hypugaea).

When the project matures to the remediation phase, Harris Environmental recommends a formal biological assessment, including a site visit, to determine any and all impacts to state and federally protected species of interest. The species lists would be updated at that time and a Biological Evaluation Report would provide formal species determination after analyzing potential impacts. Given the project limits and background, historic management practices, and potential remediation activities, potential future effects on the species listed in the 2017 Biological Report are not anticipated.

2.3 Summary of Previous Investigations

2.3.1 1982 PCB Investigation The BIA investigated the Site for PCBs in 1982 and found high concentrations of PCBs, above 50 parts per million (ppm), in near‐surface and subsurface soil north of the old diesel building and at the northeast corner of the transformer storage area. Following this investigation, ground surfaces with high PCB concentrations were paved with asphaltic concrete pavement as an interim measure to limit PCB migration and to mitigate employee health hazards (BIA RFP, 2013).

2.3.2 1991 PCB and UST Investigations The BIA contracted Gutierrez‐Palmenberg, Inc. (GPI) to more fully assess PCB contamination throughout the entire Site in 1991. GPI collected soil samples across a 50‐foot grid to delineate PCB contamination previously documented in the 1982 PCB Survey Report. GPI collected samples at depths ranging from 0 to 1 foot bgs from both paved and unpaved areas and at a depth of 5 feet bgs in selected locations. Results of the 1991 investigation identified five distinct areas of PCB contamination at the Site, all having PCB concentrations above 50 ppm to a depth of 1 foot bgs. Three of these areas had been paved nearly a decade earlier.

GPI indicated that additional sampling locations contained PCB concentrations of less than 50 ppm, although the copy of GPI’s report did not contain boring location maps or laboratory reports that supported this conclusion. Samples reportedly were collected mainly by hand excavation from ground surface to a 1‐foot depth. In addition, GPI collected soil samples at selected locations with a drill rig up to 5 feet bgs. Available 1991 GPI report pages documented five areas that contained PCB concentrations in soil above 50 ppm and designated as PCB areas of concern (AOCs) 1 through PCB AOC 5 in the GPI report (see Figure 4).

The 1991 GPI investigation also evaluated potential TPH fuel at two locations at the SCIP Maintenance Yard: (1) adjacent to the 100,000‐gallon diesel above‐ground storage tank (AST) located immediately northeast of the former power plant and (2) the former pump dispenser island area located near the southeast corner of Building 113. The 1991 report indicated TPH was detected at up to 16,000 milligrams per kilogram (mg/kg) at depths up to approximately 30 feet bgs. In the project Work Plan, TPH is addressed only in areas where it coexists with PCBs for either characterization of PCB distribution or implementation of a PCB remedy.

2.3.3 2014–2016 Assessment of Petroleum Contaminated Soil & Removal of Fuel Storage Tanks javascript:__doPostBack('ctl00$ctl00$body$homebody$RecentDocuments$C$RecentDocumentsControl$RecentDocumentResults$ctl00$DocumentNumberLink','')

The BIA contracted E W Wells Group to investigate PCB contamination at the Site, planned and implemented with technical support and direction provided by U.S. Environmental Protection Agency (USEPA), Region 9 TSCA Program Office. 2015 PCB Site Assessment results indicated localized and extremely shallow areas, both in the maintenance yard and on adjacent, private properties, contaminated by past PCB transformer oil releases containing Aroclors 1242, 1254, and 1260 (E W Wells Group, 2017). Figure 5 shows the areas of investigation, including the Exclusion Areas and the sampling grid used. The data generated from the 2016 Preliminary Assessment constitute the data used to develop the project Work Plan.

E W Wells Group subcontracted with Southwest Hazard Control (SWHC) to remove five ASTs. The tank debris was sent to a material destruction service provider for recycling (E W Wells Group, 2016). Twenty soil borings were drilled in the areas impacted by petroleum releases (TPH AOCs 1, 2, and 3) to depths of up to 60 feet bgs.

Soil samples collected from the borings were analyzed for TPH, PCBs, and PAHs. In addition, seven trenches were excavated to approximately six feet deep. No PCBs were detected in soil boring samples in TPH AOC 1 or TPH AOC 3 at concentrations greater than 0.23 mg/kg.

Generally, the extent of TPH in near‐surface soil was delineated to regulatory screening levels during the 2014‐ 2016 site characterization. TPH Concentrations in AOC 2 greater than 500 mg/kg was detected to a depth of 50 feet bgs, and PCB concentrations in nine samples were greater than 1.0 mg/kg. According to E.W. Wells 2017, “PCB concentrations in the AOC 2 area appeared to be generally associated with surficial, or near‐surface soils, and did not correlate well with the higher TPH concentrations.” PCB concentrations above 1.0 mg/kg were detected at 3.5 feet in four borings and at 8.5 feet bgs in two borings. Anomalous detections of PCBs were found in boring B‐5 and B‐19 at 28.5 feet bgs (4.7 and 1.6 mg/kg, respectively), and in boring B‐3 (1.0 mg/kg) at a depth of 38.5 feet bgs, “which may be attributable to cross‐contamination and carry‐down during drilling.”

Additionally, E.W. Wells Group drilled two soil borings to identify and assess potential contamination the former herbicide and pesticide storage area of the SCIP Yard. Four (4) soil samples were analyzed for chlorinated herbicides and chlorinated pesticides with no target contaminants detected in any of samples.

3.0 HUMAN HEALTH RISK EVALUATION

A human health risk assessment (HHRA) approach was used to develop the sampling design for the project Work Plan. PCBs are known to exist currently at concentrations above human‐health risk‐based screening levels in soils at and around the perimeter of the Site, based on previously collected soil samples. The purpose of the SSI is to improve definition of the extent of PCBs in soil at and around the Site. Once the extent of the PCBs is sufficiently defined, the BIA can develop a strategy to protect the health of onsite and offsite commercial workers and future hypothetical offsite residents from PCB exposure.

3.1 Data Evaluation

The HHRA used the data reported in the Preliminary Assessment Report (E W Wells Group, 2017). Samples were collected in the 0–3‐inch or 3–12‐inch soil depth intervals, and data from both soil depth intervals were included in the assessment. The risk evaluation relied on the E W Wells Group’s (2017) report for the assignment of sample locations for each exposure area. Several sample locations along the fence line in the northeast corner and the southwest corner of the property that were assigned to the perimeter area are located just inside the Site boundary.

Conversely, in a few cases, the onsite sample was considered as part of the perimeter area. These discrepancies do not impact the proposed sample locations but will need to be considered when the risk is re‐evaluated following collection of the proposed samples.

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3.2 Human Health Conceptual Site Model

A conceptual site model (CSM) was developed for the Site. A CSM graphically shows how the PCBs were transported through the environment and how relevant receptor populations could be exposed to the PCBs (see Figure 6). It is assumed that commercial workers working onsite could be exposed to the PCBs in the soil by incidental ingestion, dermal contact, and inhalation. Note that current onsite activities limit commercial workers’ time onsite. The maintenance yard is primarily used to store equipment that workers access at the beginning and end of each offsite work assignment. Currently no workers remain onsite for an 8‐hour work day in areas where the PCB‐contaminated soil is located. The maintenance yard is fenced and access is restricted. The HHRA uses a standard commercial exposure scenario consistent with the USEPA (e.g., assumes an 8‐hour work day), which is in excess of actual current working conditions, and is therefore considered to be a conservative approach given current conditions. The Perimeter Area–East is a railroad right‐of‐way and exposures in this area would also be considered commercial, although typically no workers are present. The other perimeter areas (offsite) are considered for future potential residential exposures.

3.3 Human Health Exposure Areas

Human health exposure areas are shown on Figures 3, 4, and 5, and include the following:

Offsite exposure areas (identified as Perimeter Areas) (Figure 3)

Perimeter Area–Northwest

Perimeter Area–North

Perimeter Area–East

Perimeter Area–Southwest

Perimeter Area–West

Onsite exposure areas (Figures 4 and 5)

Historical PCB Areas of Concern 1–5 (five exposure areas)

Exclusion Areas 1–4 and the remainder of the sampling grid not encompassed in a previously defined exposure area (called “GRID” in the remainder of the text).

3.4 Risk Characterization

Exposure areas were evaluated for risk to human health by developing an exposure point concentration (EPC) using the existing PCB concentration data and comparing the EPC to the USEPA’s RSLs protective of a residential or commercial exposure scenario, as appropriate, at the 1x10‐6 risk level. In the National Oil and Hazardous Substances Pollution Contingency Plan, the USEPA states, “For known or suspected carcinogens, acceptable exposure levels are generally concentration levels that represent an excess upper‐bound lifetime cancer risk to an individual between 1x10‐6 and 1x10‐4.” Cancer risks less than or equal to 1x10‐6 are generally considered de minimis for unrestricted use.

Risks within the risk range require additional discussion with stakeholders to evaluate site‐specific factors that may influence the exposures. Risks greater than the lower end of the risk range of 1x10‐4 are considered unacceptable and require action.

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A 95% upper confidence limit (UCL) was the representative statistic used for the EPC. The 95% UCL was developed with the latest version of USEPA ProUCL software, version 5.1.002. The program’s recommended UCL is presented as the EPC compared with the RSL. Conclusions and recommendations based on this risk screening analysis include the following:

3.4.1 Offsite Exposure Areas

1) The Perimeter Areas Northwest, West, and Southwest have exposure point concen‐ trations (no detections for Perimeter Area–Northwest, 0.131 mg/kg for Perimeter Area– West, 0.102 mg/kg for Perimeter Area–Southwest) below the 0.23 mg/kg residential screening level. This comparison indicates the residential risk is less than 1x10‐6 and is considered de minimis (i.e., acceptable).

2) The Perimeter Area–North has 132 samples with 77 detected concentrations greater than 0.23 mg/kg and an EPC of 3.04 mg/kg, indicating risk greater than the departure point of 1x10‐6 if the 0.23 mg/kg screening value is applied.

3) Perimeter Area–East is the Union Pacific right‐of‐way and its 1.04 mg/kg EPC is slightly greater than the commercial/industrial screening level of 1 mg/kg. Several locations have concentrations greater than the hot spot target value of 2 mg/kg. The eastern corner of Perimeter Area–North, the northern portion of Perimeter Area–East, and the northeastern part of the onsite GRID area represents an area into which surface water runoff may have carried PCB contamination.

4) Due to weathering and environmental transformations, Aroclor mixtures may not main‐ tain their original composition once they are released into the environment. Because of the different characteristics of the individual congeners that make up the mixtures, differences may exist between the source materials and the PCBs observed in the environment (Van den Berg et al., 1998). The risks calculated in this HHRA implemented the risk characteristics of the Aroclors analyzed to date. To confirm this is representative of Site risk, the project Work Plan proposes several samples be collected for both Aroclor and PCB congener analysis to address this uncertainty. This sampling is recommended to take place in an offsite exposure area where residential exposures could occur in the future.

3.4.2 Onsite Exposure Areas

Appendix D of the project Work plan presents further details of the EPC calculations and risk analysis for each of exposure area. The analytical data evaluated in the EPC calculations is provided electronically to Offerors, upon request, via compact disc.

• The risks and hazards estimated for the Site, including PCB AOCs 1–5, are 8.1x10‐5 and thus within the risk range. It should be noted that several elevated PCB concen‐ trations in the PCB AOC 1‐5 exposure units exceed criteria established under TSCA; therefore, it is anticipated that risk managers at the Site will consider the risks asso‐ ciated with PCB AOCs to be unacceptable.

• The carcinogenic risk to commercial workers when the EPC is calculated using concentration data from the Exclusion Areas and GRID exposure area (removing the data from the PCB AOCs) is 1.9x10‐6, which is at the low end of the USEPA’s risk range of 1x10‐4 to 1x10‐6.

• In 18 samples at 14 locations in the Exclusion Area and GRID exposure unit, total Aroclors were detected at a concentration of 10 mg/kg or greater. If these sample points are removed from the ECP calculation, the resulting risk is 5.7x10‐7, which is below 1x10‐6 and thus considered de minimis.

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4.0 STATEMENT OF WORK

This statement of work (SOW) is derived from the human health risk analysis, and stakeholder feedback. Figures 7–9 show the proposed sample locations. Table 4‐1 summarizes the proposed sample numbers, analytical method, sampling depth, and rationale.

The purpose of the implementation of the SSI Work Plan is to improve definition of the extent of PCB in soil and/or groundwater within and around the Site, and to mitigate PCB contamination. In the project WP, TPH shall be addressed only in areas where they coexist with PCBs, either to characterize PCB distribution or implement a PCB remedy.

4.1 Additional On/Off Site Sampling/Assessment of Contamination

BIA is undertaking sampling to determine what, if any, remediation is necessary under a risk‐based cleanup approach defined in TSCA, 40 CFR § 761.61, relative to established PCB Target cleanup levels (see Table 1, Section

4.3 below). Risk assessment results, using available samples, indicate PCB concentrations in the established exposure areas pose risks within or below the USEPA risk range. However, the TSCA has established a variety of PCB criteria that a self‐implementing cleanup typically follows, which may also be considered for a risk‐based cleanup such as proposed here. Additionally, BIA and USEPA have had ongoing discussions of potential cleanup objectives. The following items were also considered when selecting locations for additional sampling:

1. TSCA regulations for a self‐implementing cleanup indicate that no action is required for concentrations at or below 25 mg/kg for porous surfaces (which include asphalt or soil) in low occu‐ pancy areas (defined as areas occupied by individuals without dermal or respiratory protection for fewer than 840 hours per calendar year).

2. EPA has requested that BIA cap or remove the PCB concentrations equal to or exceeding 10 mg/kg within the maintenance yard (onsite). Consultation with USEPA’s risk assessment team indicated such action would result in acceptable risks, as confirmed in the scenario considered in the HHRA included in the Work Plan.

3. Following consultation with Union Pacific, USEPA has indicated it would not request land use restrictions on the adjacent property to the east if the PCB concentrations greater than or equal to 2 mg/kg are defined as hot spots and remediated.

4. TSCA regulations for a self‐implementing cleanup indicate that high occupancy areas (including a residence, full‐ time work area, or school) require no action for concentrations of PCBs at or below 1 mg/kg.

5. EPA’s RSL based on 1x10‐6 cancer risk is 0.23 mg/kg for residents and 1 mg/kg for commercial workers.

6. The correlation of TPH and low to trace concentrations of PCBs in shallow soil and at depths of 24, 38 and 50 feet in the TPH AOC 2 area suggest that PCBs may have migrated down when co‐ mingled with TPH. As perched groundwater has been reported at depths of 50 and 100 feet within 0.5 miles of the SCIP facility, the Site needs to be investigated to determine if perched groundwater occurs beneath the Site and, if so, whether such perched water is impacted by TPH, Polycyclic Aromatic Hydrocarbons (PAHs), and/or PCBs.

The work plan proposes the following PCB target levels:

Onsite: 10 mg/kg javascript:__doPostBack('ctl00$ctl00$body$homebody$RecentDocuments$C$RecentDocumentsControl$RecentDocumentResults$ctl00$DocumentNumberLink','')

Perimeter Area–East: 2 mg/kg as indication of a hot spot

Perimeter Area–North, –South, and –Southwest: 0.23 mg/kg as compared to an EPC.

Most of the proposed sample locations are concerned with horizontal delineation. The potential for onsite excavation is severely limited due to the Grewe prehistoric archaeological site. It is anticipated that the PCB AOCs shall be remediated primarily by capping. Therefore, vertical delineation is not proposed around the PCB AOCs.

Other onsite areas (northeast corner and around isolated concentrations greater than 10 mg/kg) may require limited surface soil removal, and limited vertical delineation has been proposed to distinguish between PCB contamination that is surficial (0–3 inches) versus shallow (3–12 inches).

Surface or shallow soil removal is anticipated for some locations on adjacent properties. As appropriate, vertical delineation of contaminant impacts is proposed.

4.2 Soil Sampling Locations

4.2.1 Perimeter Area–South

A new perimeter area is established on adjacent state‐owned property south of the maintenance yard.

Sampled PCB concentrations in adjoining portions of the maintenance yard and the existing Perimeter Area– Southwest are typically low to undetectable. A few PCBs were detected in the southwest corner of the maintenance yard, however. Perimeter–Area Southwest addressed these detections, but the state of Arizona has noted that the remainder of its adjoining property has not been sampled.

While reaffirming that all samples surrounding this adjacent property either had no detectable PCBs or showed very low concentrations (well below established residential criteria), BIA has agreed to establish a new Perimeter Area–South, as shown on Figure 7, bounded on the north by the property fence line (corrected in 2016), on the west by Perimeter Area–Southwest, and on the east by Union Pacific property. The southern boundary aligns with the Perimeter Area–Southwest boundary.

Seven proposed locations (see Figure 7) shall be sampled at the surface (0–3 inches) and analyzed for Aroclors. The purpose of these samples is to characterize PCB concentrations across Perimeter Area–South.

4.2.2 Perimeter Area–North and Perimeter Area–East

Elevated PCB concentrations near to or above 2 mg/kg are present on adjacent property in Perimeter Area– North (maximum total Aroclor concentration of 34 mg/kg) and the northern end of Perimeter Area–East (maximum total Aroclor concentration of 19 mg/kg). Figure 8 shows proposed sample locations in the northern part of the Site, described as follows:

• To address data gaps in the Perimeter Area–North sampling, 18 additional surface (0–3‐inch) samples are proposed for the interior of the area (grid cells C5, B5, B6, B7, B8, B9, B13, A13, A16 and B16).

Surface samples shall be collected at each location and shallow subsurface (3–12‐inch) samples shall be collected at two locations near previously elevated PCB concentrations.

• Perimeter Area‐North is thickly vegetated with trees and bushes, which prevent access for collection of additional soil samples. Access to the proposed samples locations will first require cutting and removal of javascript:__doPostBack('ctl00$ctl00$body$homebody$RecentDocuments$C$RecentDocumentsControl$RecentDocumentResults$ctl00$DocumentNumberLink','') mesquite and palo verde trees, scotch broom, and creosote bushes. An estimated volume of 80 cubic yards of green waste will require removal, transport and disposal. Vegetation removal / clearing services shall be provided by BIA/SCIP, as required.

• To address the coverage of samples to the east of Perimeter Area–North near the railroad right‐of‐way, an additional five surface (0–3‐inch) samples are proposed (cells A17, B17, C17).

• The PCBs have likely weathered over time. Five surface (0–3‐inch) samples from cells C7, C11, B12, B14, and D16 shall be analyzed for both Aroclor and PCB congeners. These locations were chosen because they showed higher PCB concentrations from previous sampling (1.4 mg/kg, 8.5 mg/kg, 9 mg/kg, 12 mg/kg, and 34 mg/kg), are located offsite, and in the area that may have collected surface water runoff.

Samples shall be collected from full‐sun areas with no shade.

4.2.3 Onsite – Northern Maintenance Yard

PCB detections in the northeast corner of the property include concentrations above 10 mg/kg and a maximum Aroclor concentration of 89 mg/kg. Figure 8 shows proposed sample locations, described as follows:

• Six additional sampling locations are proposed for cells D15 and E15 to delineate the concentration of 19 mg/kg found in cell D16 and to assess whether the somewhat elevated concentrations of cell E16 (maximum 4.9 mg/kg) may increase further into the property. Surface (0–3‐inch) shall be collected at each location and shallow subsurface (3–12‐inch) samples shall be collected at two locations near previously elevated PCB concentrations.

• 17 sampling locations are proposed to delineate the elevated concentrations along the maintenance yard’s northern edge (89 mg/kg and 12 mg/kg in D12, and 33 mg/kg in D14). Some of the previous samples on adjacent property to the north were collected from the 3–12‐inch depth interval and showed slightly elevated concentrations. Therefore, surface (0–3‐inch) shall be collected at each location and shallow subsurface (3–12‐inch) samples shall be collected at three locations near previously elevated PCB concentrations.

4.2.4 Onsite – Transformer Storage Areas and PCB Areas of Concern Additional samples are necessary to bound previously detected PCB concentrations greater than 10 mg/kg in the central portion of the Site, around or near the previously identified PCB AOCs. Figure 9 shows the proposed locations for surface (0–3‐inch) samples. The locations with concentrations greater than 10 mg/kg are concentrated in and around former transformer storage areas 1 and 2. Additional samples are also proposed to better characterize the east side of the Maintenance Yard between the PCB AOCs 1, 2, and 3 and the eastern fence. Figure 9 shows proposed sample locations in the central part of the Site, described as follows:

• Grid cells T3 and R3 along the maintenance yard’s western boundary have elevated Aroclor concentrations of 18 and 67 mg/kg. Eight sample locations are proposed surrounding these detections.

• Grid cells P5, Q5, and R5 have elevated total Aroclor concentrations of 11, 17 and 20 mg/kg. These locations are just east and northeast of PCB AOC 5. Nine additional samples are recommended.

• A total Aroclor concentration of 16 mg/kg was found in cell Q10 located just west of PCB AOC 4. Three samples are proposed around this location.

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• Total Aroclor concentrations of 32 mg/kg (S13), 25 mg/kg (R12), and 79 mg/kg (Q13) were found near PCB AOC 3. Eleven samples are proposed around these locations.

• The west side of PCB AOC 1 was found to have a total Aroclor concentration of 25,000 mg/kg. The next sample to the west, in cell N12, has a concentration of 10 mg/kg. Six samples are proposed around this area.

• Two locations are proposed on the north side of PCB AOC 4 (P11) which has total Aroclor concentrations of 110 and 27 mg/kg.

• Three locations are proposed north of PCB AOC 1 (N14 and N15), which has total Aroclor concentrations of 40 to 71 mg/kg.

• Fourteen samples are proposed between PCB AOCs 1, 2, and 3 and the eastern yard boundary. The eastern sides of these PCB AOCs have concentrations as high as 230, 390, and 60 mg/kg, respectively.

TPH and PCB data collected in 2014 from the area south of TPH AOC 2 show TPH and PCBs at the surface and at depths of 8.5 and 48.5 feet in Boring B‐4. PCBs also were detected at depths of

8.5 and 38.5 feet in Boring B‐18 (south of TPH AOC2). No fuel source was identified in the area of Boring B‐4 (EW Wells 2017). EW Wells suggests possible temporary storage of fuel drums or surface spills may be the source. However, waste transformer oil historically was spread across the Site for dust control. This practice may be the source of detected PCBs and TPH in the area of TPH AOC 2 Boring B‐4.

PCB AOC 2 and TPH AOC 2 both have surface soil data with PCB concentrations over 100 mg/kg at some locations and low to trace PCB concentrations at depth. The correlation of TPH and PCBs in shallow soil and at depths of 24, 38 and 50 feet in the TPH AOC 2 area suggests that PCBs may have migrated down when co‐ mingled with TPH. The 2014 investigation sampled for TPH as an indicator of impacts from fuel releases within TPH AOC 1, TPH AOC 2 and TPH AOC 3 – the former fuel storage tank areas, the buried fuel line, and the area of the former distribution pump island, respectively. As no historical fuel releases were documented in PCB AOC 2, no samples for TPH analysis were collected from PCB AOC 2.

The detection of PCBs and TPH at TPH AOC2 Boring B‐4 and the detection of PCBs at depth at TPH AOC2 Boring B‐18, suggest PCBs detected at depth may have resulted from co‐mobilization of the PCBs with the transformer oil or from earlier fuel management practices during the time the transformer oil was spread at the facility.