Activity Overview

Table of Contents

Time Critical Removal Action
RCRA Facility Investigation/Remedial Investigation
Human and Ecological Risk Assessment
Coordination with Tribal Nations and Stakeholders

The California Department of Toxic Substances Control (DTSC)The department within the California Environmental Protection Agency in charge of the regulation of hazardous waste from generation to final disposal. DTSC oversees the investigation and cleanup of hazardous waste sites. and the U.S. Department of the Interior (DOI)The United States department charged with conservation and development of natural resources. The U.S. Department of the Interior uses sound science to manage and sustain America’s lands, water, wildlife, and energy resources, honors our nation’s responsibilities to tribal nations, and advocates for America’s island communities. are the lead governmental agencies responsible for the environmental investigation and cleanup of the Topock Project Site (Site). The agencies oversee Pacific Gas and Electric Company’s (PG&E's) actions to protect the Colorado River and to clean up soil and groundwaterWater beneath the Earth’s surface that flows through soil and rock openings (aquifers). contamination in the vicinity of the PG&E Topock Compressor Station (Station). Environmental investigation and groundwater monitoring have been under way at the Site since 1997.

PG&E is conducting soil investigation and remedial activities at the Site under the Resource Conservation and Recovery Act (RCRA)A 1976 amendment to the first federal solid waste legislation, the Solid Waste Disposal Act of 1965. In RCRA, Congress established initial directives and guidelines for U.S. EPA to regulate and manage solid waste, including hazardous waste. RCRA established a regulatory system to track hazardous substances from the time of generation to final disposal. The law requires safe and secure procedures to be used in treating, transporting, storing and disposing of hazardous wastes. RCRA was designed to prevent new, uncontrolled hazardous waste sites. and the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA)Commonly known as Superfund, this law created a tax on the chemical and petroleum industries and provided broad federal authority to respond directly to releases or threatened releases of hazardous substances that may endanger public health or the environment. CERCLA established prohibitions and requirements concerning closed and abandoned hazardous waste sites; provided for liability of persons responsible for releases of hazardous waste at these sites; and established a trust fund to provide for cleanup when no responsible party could be identified. The law authorizes two kinds of response actions: Short-term removals, where actions may be taken to address releases or threatened releases requiring prompt response. Long-term remedial response actions, that permanently and significantly reduce the dangers associated with releases or threats of releases of hazardous substances that are serious, but not immediately life threatening., pursuant to agreements with DTSC and DOI, respectively.

The soil medium is currently in the RCRA Facility Investigation/Remedial Investigation (RFI/RI)An investigation that occurs in the corrective action process following a Facility Assessment under RCRA and/or a Site Inspection under CERCLA. It is an in-depth study designed to gather data needed to determine the nature and extent of contamination at a site. phase of the cleanup process. Soil and related investigation activities cover 15 areas located outside the Station fence line (see figure below) and 27 areas located inside the Station fence line (see figure below). The perimeter areas adjacent to the Station fence line and the storm drains leading from the Station to areas outside the fence line are also included in the investigation.

Soil sampling and related Soil Investigation field work was completed between December 2015 and March 2016, January through March 2017, and the latter part of April 2017. That work fulfilled requirements of the Topock Soil Facility Investigation/ Remedial Investigation (RFI/RI) Work Plan and Data Gap Work Plans #1, #2, and #3. Field work included:

  • Collection of soil samples at 364 locations.
  • Trenching of 15 locations to evaluate possible contamination.
  • Collection of sediment and pore water samples from 10 locations at the edge of the Colorado River by the East Ravine.

After sample collection was completed, results were evaluated by DTSC, the U.S. Department of the Interior (DOI), and PG&E to determine if additional data collection is needed to complete the Soil Investigation and evaluate potential next steps. The agencies and PG&E balanced the data collection necessary with Tribes request to minimize site intrusion by maximizing the use of archived samples and collection of samples from existing locations.

On June 20, 2017, DTSC and DOI determined that the Soil RFI/RI field work was completed and concurred with PG&E to move forward with the risk evaluation process per the approved Risk Assessment Work Plan and addendum. In addition, PG&E will commence the preparation of the Soil RFI/RI Report.

Map of Figure 1-2 Soil RFI/RI Work Plan  Map of Figure 1-3 Soil RFI/RI Work Plan

(Click on images above for larger view)

Time Critical Removal Action

On June 24, 2009, DOI directed PG&E to remove debris that had been deposited within a ravine south of the Topock Compressor Station (Station) through the issuance of the Area of Concern (AOC)Areas outside of the source remediation site that are being evaluated and may be contaminated due to past practices and/or proximity to the source site. These areas are subject to the overall site’s environmental investigation to determine if they will also need to be remediated. 4 Debris Ravine Time-Critical Removal Action (TCRA)A time sensitive action to stabilize and mitigate the threat of release of contaminated material. It is not intended to substitute for any remedial activities or be the final remedy. Memorandum. The TCRA was necessary to control the potential migration of contamination from PG&E to the Havasu Wildlife Refuge property. Work planning and consultation for the removal activities immediately ensued, and DOI approved PG&E’s Work Plan on December 15, 2009. The AOC 4 Debris Ravine TCRA field activities were performed from December 2009 through December 2010 in compliance with the DOI TCRA Work Plan. During this time, approximately 11,800 tons of waste was removed from the AOC 4 Debris Ravine. On March 15, 2011, PG&E completed the Implementation Report for the Time-Critical Removal Action at AOC 4, Pacific Gas and Electric Company Topock Compressor Station, Needles, California

Resource Conservation and Recovery Act (RCRA) Facility Investigation/Remedial Investigation (RFI/RI)

The regulatory agencies directed PG&E to proceed with the supplemental soil investigation necessary to complete the third Volume of the Resource Conservation and Recovery Act Facility Investigation/Remedial Investigation (RFI/RI) report. See the RFI/RI page under Groundwater for discussion of Volumes 1 and 2. The purpose of the soil investigation was to collect data to characterize the nature and extent of soil contamination, to evaluate potential for soil contamination to affect the groundwater, and to support the soil risk assessmentA study prepared to assess health and environmental risks due to potential exposure to hazardous substances., as well as soil remedy selection (if needed).

The first phase of soil investigation in areas outside of the Station was completed in 2008. Soil data have been reviewed, and data gaps have been identified. A Draft Soil RFI/RI Work Plan, which describes the additional data needed to address the identified data gaps at the Site, was prepared and submitted on May 6, 2011. Comments were received from Tribal Nations and agencies. A revised Soil RFI/RI Volume I Work Plan was submitted on January 14, 2013. An addendum to the Soil RFI/FI Work Plan Volume I work plan was submitted May 30, 2014. Pursuant to the California Environmental Quality Act (CEQA)A law mandating review of environmental impact of governmental action. It requires that public agencies study the significant environmental effects of proposed activities and that the public be informed and allowed to comment on project decisions. DTSC evaluated the environmental impacts associated with the soil investigation in the Final Soil EIR, DTSC filed a determination and certified the Final Soil EIR on August 24, 2015 along with the approval of the Final Work Plan. DOI also approved the Soil RFI/RI Work Plan on August 24, 2015. PG&E began the soil field investigation on October 29, 2015 and completed it in April 2017. The results of the investigation will be used to support the soil risk assessment and the data will be included in the Volume 3 - RFI/RI Report on Soil Characterization. Volume 3 of the Soil RFI/RI report is anticipated to be completed in late 2020.

Each Approved RFI/RI volume (and its addendum if applicable) will be released to the public and posted in the Information Repositories and the Document Library.

Human and Ecological Risk Assessment

The Risk Assessment Work Plan was submitted on August 25, 2008. An addendum was submitted on February 4, 2009. On September 19-20, 2013, DTSC, DOI, PG&E, and Tribal Nations met to discuss amendments to the Soil Risk Assessment Work Plan. DTSC approved the Soil Risk Assessment Work Plan and addendum on February 4, 2009 and DOI approved on February 5, 2009. A Final Risk Assessment Work Plan Addendum II was submitted on June 29, 2015, and contains updated information relevant to soil risk assessment activities and evaluation based on comments received by Tribal Nations, agencies, and stakeholders. DTSC conditionally approved the Soil Risk Assessment Addendum II on August 31, 2015 (clarified on September 15, 2015) and DOI conditionally approved the Addendum 2 on September 8, 2015. With the completion of the soil investigation in April 2017, the Soil Risk Assessment is now being prepared.  The risk assessment will provide information about potential human health threats and ecological risks posed by affected soil, and assist risk management decision making on the need for soil remediation. The Soil Risk Assessment work is anticipated to be completed in 2020. 

Coordination with Tribal Nations and Stakeholders

DTSC and DOI are coordinating the investigation and cleanup of the Site with multiple state and federal agencies, Tribal Nations, and stakeholders regularly as part of a Consultative Workgroup (CWG)A group consisting of stakeholders and multiple state and federal agencies that have an interest in the cleanup of a contaminated site, and meet regularly to discuss actions and make decisions., the Technical Workgroup (TWG)A focused stakeholder subgroup of the Consultative Work Group (CWG) where various stakeholders and their consultants discuss technical project related issues in greater detail which are then reported back to the CWG., the Clearinghouse Task Force (CTF)A group formed to develop and implement processes and tools to improve communications and enhance Topock stakeholder understanding of project technical and regulatory information., and the Topock Leadership Planning Partnership (TLP)Forum that enables senior officials to provide input to the regulatory agencies on the direction of actions necessary to complete the Topock project.

The CWG, established by DTSC in March 2000, consists of agencies, Tribal Nations, and other entities that have an interest in protecting the Colorado River and the surrounding environment. The goal of the CWG is to allow timely input on proposed activities and decisions to be made. In addition to the CWG, DTSC conducts outreach to the public, governmental representatives (including federal, state, county, and city elected officials and staff), and Tribal Nations leaders and staff.

DTSC established the TWG as a subgroup of the CWG. The TWG meets to discuss various specific Project-related issues in greater detail, with an emphasis on the technical aspects of the Project, which are then reported back to the CWG. All CWG members are invited to send staff to participate in the TWG. Technical areas of discussion include groundwater investigation, hydrogeology, soil investigation, modeling and engineering design, human health and ecological risk assessments, remediation alternatives, and remedial design for the Topock Project. The TWG usually meets monthly to quarterly depending on Project needs.

DTSC meets regularly with federal agencies, stakeholders, Tribal Nations, and PG&E representatives, as part of the CTF. The CTF has been formed to develop and implement processes and tools to improve communications and enhance Topock stakeholder understanding of Project technical and regulatory information. The goal is to foster timely and effective project management and early collaboration, and provide information to the state and federal agencies for decision making on the Topock Project.

The TLP was created as a result of an understanding that a forum was needed to enable senior officials to provide input to DTSC and DOI on the direction of actions necessary to complete the Topock Project. The purpose of the TLP is to exchange information, views, and opinions on various actions proposed by DTSC and DOI with respect to the development, selection, and implementation of the groundwater remedy for the Site. The intent is not government-to-government consultation, but to provide a senior-level perspective of each participant’s interest, and gain understanding of differing points of view that could be considered before critical decisions are made by the agencies. The TLP has met several times since 2008, prior to critical Project decisions. 

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