CTR072298_Amendment_3_-_Adds_Key_Personnel.pdf

Rev. 03-05-2025

CONTRACT

AMENDMENT

CONTRACT NO.: CTR072298

AMENDMENT NO.: 3

TITLE: ASRAC Assessment and Remediation of Hazardous Substances CONTRACTOR: Geosyntec Consultants, Inc.

ADEQ PROCUREMENT

1110 W. Washington Street Phoenix, AZ 85007 602-771-4140

THE PURPOSE OF THIS AMENDMENT IS TO:

In accordance with the Uniform Terms and Conditions, 5.1 Amendments and Special Terms and Conditions, 3.7 Subcontract, this contract is hereby amended as follows:

1. Add the following Key Personnel to this contract:

• Arthur Wickham– PL V

2. All other Requirements, Specifications, Terms and Conditions remain unchanged.

THE ABOVE REFERENCED AMENDMENT IS A

UNILATERAL ACKNOWLEDGEMENT OF

CONTRACTOR’S APPROVED CHANGED

REQUEST.

ARIZONA DEPARTMENT OF ENVIRONMENTAL QUALITY

The above referenced Amendment is hereby executed this 3rd day of December 2025 at Phoenix, Arizona.

Ana Machiche Procurement Officer

Available online at Arizona Procurement Portal (APP) eProcurement System https://app.az.gov https://app.az.gov/

ARTHUR WICKHAM, PG, CPG, CHG, PMP

Professional Level V

Contaminated Site Investigation Per- and Polyfluoroalkyl Substances (PFAS)

Groundwater, Soil and Soil Vapor Remediation, Site Closure Applied Research

Water Resources, Water Quality

EDUCATION

• MSc, Hydrologic Science and Engineering (Hydrology), Colorado School of Mines, Golden, CO,

• BSc, Geosciences (Geology), University of Arizona, Tucson, AZ, 2013

REGISTRATIONS AND CERTIFICATIONS

• Professional Geologist (PG) – State of California No. 9449; State of Wyoming No. 4098

• Certified Professional Geologist (CPG) – American Institute of Professional Geologists (AIPG)

No. 12237

• Certified Hydrogeologist (CHG) – State of California No. 1074

• Project Management Professional (PMP®) – Project Management Institute (PMI) No. 4110590

• EM 385-1-1 Supervisor (24-Hour) Training

• OSHA HAZWOPER 40-Hour Training, 8-Hour Annual Refresher

• OSHA 8-Hour HAZWOPER Supervisor Training

• OSHA 10-Hour Construction Training

• First Aid, CPR, AED Training

CAREER SUMMARY

Mr. Wickham is a Certified Project Manager (PMP®), Licensed /Certified Professional Geologist (PG, CPG) and Certified Hydrogeologist (CHG) with 13+ years of experience in environmental assessment and remediation consulting services. He has extensive experience leading teams in designing and delivering engineered solutions related to groundwater, soil and soil vapor remediation to federal, transportation, chemical, oil and gas, and mining sector clients - most recently specializing in PFAS investigations at military installation project sites.

While contributing hydrogeology subject matter expertise, Mr. Wickham leads environmental site investigation programs, specializing in conceptual site model development, contaminant fate and transport, work planning, quality control, data interpretation and visualization, technical reporting, and public outreach. Mr. Wickham possesses advanced experience in Project and Program Management, with

Arthur Wickham, PG, CPG, CHG, PMP expertise assembling and providing leadership to multi-disciplinary technical teams implementing complex remedial investigations and feasibility studies.

Wickham has demonstrated successes in marketing, business development, and client account management.

His organizational leadership experience spans multiple industry applications and includes department and office management (of various sizes and geographies), staff supervision and mentoring, and business processes definition and improvement.

Contaminated Site Investigation, PFAS

PFAS Site Investigation & Feasibility Study, Confidential Industrial Site; North Dakota Role: Program Manager, Subject Matter Expert (PFAS) Scope/Description: Conducted site investigation to determine nature and extent of PFAS impacts in environmental media (soil and groundwater) including 3D conceptual site model (CSM) development and stratigraphic flux analysis, performed desktop groundwater fate and transport assessment to support groundwater receptor survey, and conducted feasibility study for remedial action.

Phase I PFAS Remedial Investigations at Multiple Remote Long-Range Radar Stations (LRRS), Air Force Civil Engineering Center (AFCEC), Indian Mountain, Sparrevohn, Tatalina, Cape Romanzof, Cape Newenham, & Fort Yukon, Alaska Role: Subject Matter Expert (PFAS, Hydrogeology) Scope/Description: Conducted accelerated RIs at multiple remote LRRS’ to characterize and delineate the nature and extent of PFAS-impacts at one or more validated AFFF source areas at each installation, for various media (groundwater, soil, sediment, surface water, porewater). The work included compliance with CERCLA and non-CERCLA regulations, and coordination with DoD, public, and State regulatory stakeholders.

Phase I PFAS Remedial Investigation (RI), AFCEC, Eielson AFB, Fairbanks, Alaska Role: Hydrogeology Lead Scope/Description: Conducted accelerated base-wide Remedial Investigation at Eielson AFB, Alaska to delineate the nature and extent of PFAS via adaptive high-resolution site characterization and development of a flux-based CSM to support source removal, groundwater containment, and future risk assessments. Contributed as hydrogeology lead within the technical group: focused on field work scoping and implementation, data management and analysis, and conceptual site model development to inform ranking and prioritizing source areas for removal actions determinations. Technical review results were presented to client and regulatory stakeholders via meetings/presentations. Provided additional support to development and coordination of deliverables, project work plans, and reports.

PFAS Groundwater Monitoring and Well Maintenance, AFCEC/US Army Corps of Engineers (USACE) Omaha District, Peterson Space Force Base (SFB), CO, US Air Force Academy (USAFA), Colorado Springs, Colorado

Role: Program Manager Scope/Description: Conducted quarterly groundwater monitoring for PFAS at Peterson SFB and USAFA to monitor extent of groundwater impacts site-wide and off-site; assess trends of groundwater quality, make recommendations to USAF regarding PFAS monitoring program. Performed monitoring well network inspections and maintenance.

Phase I PFAS Remedial Investigation (RI), AFCEC Ellsworth AFB, South Dakota Role: Project Manager Scope/Description: Conducted accelerated base-wide (and off-base) Remedial Investigation at Ellsworth AFB, South Dakota to delineate the nature and extent of PFAS via adaptive high-resolution site characterization and development of a flux-based CSM. Project scope also included performing a Baseline Human Health Risk Assessment (BHHRA) and Screening-Level Ecological Risk Assessment (SLERA). Managed client communications, project financials, progress reports and invoices, subcontractor and vendor contracting, client and regulatory (SDDANR, EPA Region 8) meetings/presentations coordination and deliverables, public outreach (Town Hall Meetings), project work plan development and submittal, field work scoping and implementation, data management and analysis, and conceptual site model development.

Phase I PFAS Remedial Investigation (RI), AFCEC, Peterson SFB, Colorado Springs, Colorado Role: Project Manager Scope/Description: Conducted accelerated base-wide Remedial Investigation at Peterson SFB, Colorado to delineate the nature and extent of PFAS at four AFFF source areas via adaptive high-resolution site characterization and development of a flux-based CSM. Project scope also included performing a BHHRA and SLERA, and implementation of bench and field scale treatability studies to assess in-situ soil sorption/stabilization (ISS) for source area soils. Managed client communications, project financials, progress reports and invoices, subcontractor and vendor contracting, client and regulatory (Colorado Department of Public Health and Environment [CDPHE]) meetings/presentations coordination and deliverables, project work plan development and submittal, field work scoping and implementation, data management and analysis, and conceptual site model development.

Phase I PFAS Remedial Investigation (RI), AFCEC, Buckley SFB, Aurora, Colorado Role: Project Manager Scope/Description: Conducted accelerated base-wide Remedial Investigation at Buckley SFB, Colorado to delineate the nature and extent of PFAS at four AFFF source areas via adaptive high-resolution site characterization and development of a flux-based CSM. Project scope also included performing a BHHRA and SLERA, and implementation of bench and field scale treatability studies to assess in-situ soil sorption/stabilization (ISS) for source area soils. Managed client communications, project financials, progress reports and invoices, subcontractor and vendor contracting, client and regulatory (CDPHE) meetings/presentations coordination and deliverables, public outreach (RAB), project work plan development and submittal, field work scoping and implementation, data management and analysis, and conceptual site model development.

Remedial Investigation/Feasibility Study (RI/FS), Site DA090 – RV Parking Lot Drum Site, AFCEC, Joint Base Elmendorf-Richardson (JBER), Anchorage, Alaska Role: Hydrogeology Lead Scope/Description: Conducted site-wide RI/FS to support site closure, consisting of soil and groundwater characterization and delineation. Identified multiple data gaps and potentially unidentified source soils contributing to TCE groundwater impacts. Leading technical efforts to develop scope and 2D fate and transport groundwater modelling to address data gaps and inform removal action(s) and risk assessments.

Property Sale Soil Investigation, Union Pacific Railroad, Minturn, Colorado Role: Project Manager Scope/Description: Provided project management and finalization of deliverables for a screening-level assessment of shallow soils on a property in support of sale for residential use.

Groundwater, Soil and Soil Vapor Remediation, Site Closure

Environmental Groundwater Remedy Study, AFCEC, Port Heiden Radio Relay Station (RRS), Alaksa Role: Hydrogeologist Scope/Description: A Groundwater Remedy Study was prepared for the United States Air Force (USAF) evaluating existing groundwater data to determine if the current selected remedy of Long Term Monitoring (LTM) with annual groundwater monitoring, Monitored Natural Attenuation (MNA) and Land Use Controls (LUCs) remained appropriate, or if a new revised remedy is necessary to achieve cleanup level (CUL) goals at a site historically impacted with polychlorinated biphenyls (PCBs), petroleum, oil and lubricants (POLs), and chlorinated solvents in soil and groundwater.

Remedial Action-Construction (RA-C), AFCEC, Cape Romanzof Long Range LRRS, Alaksa Role: Hydrogeologist Scope/Description: Remedial action-construction (RA-C) activities were conducted at multiple sources across a site historically impacted with PCBs, metals (lead), POLs to achieve unlimited use and unrestricted exposure (UU/UE) site closure. Activities included demolition, sampling and analysis of soils, offsite disposal of contaminated soils, and restoration of a landfill cap.

Fort Saskatchewan Facility, Dow Chemical Company, Fort Saskatchewan, Alberta, Canada Role: Project Manager Scope/Description: Conducted a vapor intrusion investigation to establish baseline environmental conditions at a site prior to building occupancy. The site activities supported Dow’s risk assessment in future property transfers and also served to assess the effectiveness of engineered controls of former waste capped adjacent to the property.

Union Carbide Corp. Torrance Facility, Dow Chemical Company, Torrance, California Role: Project Manager Scope/Description: Conducted groundwater monitoring and OMM activities at a former polyethylene manufacturing facility with multiple aquifers and free-product (DNAPL and LNAPL), conducted under a Voluntary Cleanup Agreement with the California EPA Department of Toxic Substances Control (DTSC). Monitoring activities were previously performed by another consultant. Notified the client of potential waste procedure non-compliance and reporting issues and proposed and implemented solutions in a short turnaround time. An effort was made to reassess site data and trends in order to optimize the program in 2020 (reduce sampling and reporting frequency), in cooperation with DTSC.

Former C&NW Rail Yard, Union Pacific Railroad, Casper, Wyoming Role: Senior Technical Consultant/Reviewer Scope/Description: Groundwater monitoring, monitored natural attenuation remediation, and aquifer testing activities conducted at the former fueling facility in Casper, WY. Reviewed regular reports as senior technical reviewer. The monitoring program was optimized via an in-depth Five-Year Review.

Cheyenne Railroad Fueling Site, Union Pacific Railroad, Cheyenne, Wyoming Role: Senior Technical Consultant/Reviewer Scope/Description: Groundwater monitoring, LNAPL removal, and groundwater sampling activities were conducted at the former fueling facility in Cheyenne, WY – conducted under a Remedy Agreement with the Wyoming Department of Environmental Quality (WDEQ). Reviewed regular reports as senior technical reviewer. The site is complex with multiple plumes as a result of residual free-product in the groundwater. A Five-Year Review was conducted to further assess trends and to make future recommendations to UPRR.

Nebraska Solvents Company, Union Pacific Railroad, Grand Island, Nebraska Role: Senior Technical Consultant/Reviewer Scope/Description: Groundwater monitoring and sampling activities were conducted plume-wide, primarily monitoring PCE degradation products – conducted under a Voluntary Cleanup Agreement with Nebraska Department of Environment and Energy (NDEE). Reviewed regular reports as senior technical reviewer. The monitoring program was designed to be dynamic in order to be optimized or expanded as COC trends are observed in three different monitoring ‘zones’ throughout the plume.

Site Remediation and Closure Assessment, Western Midstream LP, Colorado Role: Project Manager Scope/Description: Groundwater monitoring, site characterization and remediation at five oil and gas compressor stations to support compliance and site closure with the CDPHE Voluntary Clean-Up Program (VCUP). Groundwater and soil was impacted by chlorinated solvents and petroleum hydrocarbons. Recommended active remediation and fate and transport/monitoring natural attenuation modelling to achieve site closure at three sites. Identified significant data gaps in the existing site groundwater monitoring network. Implemented an accelerated schedule to address data gaps and to apply for site closure at three sites. Re-established relationship with VCUP after project was left unattended by previous consultant for multiple years.

Twins Inn Superfund Site Vapor Intrusion Investigation, Dow Chemical Company, Arvada, Colorado Role: Project Manager Scope/Description: Conducted a supplemental vapor intrusion investigation in and around the source area of a chlorinated solvents groundwater plume. Provided technical and risk assessment support to Dow. Identified potential vapor intrusion risk and developed a phased source area and soil vapor investigation. Work was completed outside of an EPA Consent Decree; however, heavy involvement from stakeholders and regulators (including CDPHE, the property owner, Colorado School of Mines) as well as spending cutbacks from Dow made assessing risk and technical recommendations very challenging.

Twins Inn Superfund Site Groundwater Monitoring, Dow Chemical Company, Arvada, Colorado Role: Project Manager Scope/Description: Conducted groundwater monitoring of a chlorinated solvents groundwater plume.

Additional source area investigation and vapor intrusion assessment was conducted. Utilized spatial and temporal analysis, optimized the groundwater monitoring network and associated reporting, resulting in client savings. Identified potential vapor intrusion risk and developed a phased source area and soil vapor investigation.

Cleburn Street Well Superfund Site, Union Pacific Railroad, Grand Island, Nebraska Role: Task Manager, Field Team Leader Scope/Description: Managed quarterly groundwater monitoring and sampling/maintenance of a Vapor Intrusion Mitigation System (VIMS) at a former solvents site. Scheduled and managed field events, processes, interprets and reports results (including mass removal rates) and status to the client. Lead field efforts for additional groundwater and soil source investigations. Optimized the sampling network to estimate mass removal rates of the VIMS. Identified issues related to operation and maintenance and completed timely repairs.

Former Nebraska Solvent Company, Union Pacific Railroad, Grand Island, Nebraska Role: Task Manager, Field Team Leader Scope/Description: Former company operations resulted in a solvents groundwater plume. Consulting services included soil excavation, groundwater monitoring, and indoor air monitoring. Responsible as field team leader for site air and soil vapor sampling, building surveys, and associated reporting.

Contributed technically to site characterization and hydrogeologic cross section development, to support remedial technology design.

Remediation Design/Remediation Action, U.S. Army Corps of Engineers, Cheyenne, Wyoming Role: Hydrogeologist, Task Manager, Field Quality Manager Scope/Description: The Pre-Design Investigation involved an extensive field effort to delineate the distal end of a TCE groundwater plume at a former Atlas Missile Site. Served as the field activities task manager to coordinate field staff, soil borings, sampling, and groundwater monitoring well installations. Contributed technically to site characterization and hydrogeologic cross section development as the project hydrogeologist, working closely with project engineers to aid in biobarrier design and installation.

Plume Remediation Evaluation, Rio Tinto Minerals, Boron, California Role: Hydrogeologist Scope/Description: Project objectives for the plume (Total Dissolved Solids and Arsenic) remediation evaluation included reviewing previous reports and models, identifying data gaps, characterizing aquifer properties via pump testing, and the development of a Corrective Action Plan (CAP) and CSM.

Groundwater Extraction Treatment System, Kinder Morgan Colton South Fuel Terminal, Bloomington, California Role: Hydrogeologist, Task Manager Scope/Description: This project involved the design, implementation, system maintenance and regular reporting of remedial actions at the SFPP Colton Fuel Terminal in Bloomington, CA. Contributed to the installation and development of groundwater monitoring and groundwater extraction wells to support an on-site groundwater extraction treatment system (GWETS) and numerical groundwater model to characterize and contain MTBE and other petroleum hydrocarbons. Served as the task manager for the groundwater monitoring and status reports that are submitted to the water quality control board monthly, quarterly, semi-annual and annually.

Soil Vapor Extraction Pilot Study, Drilube Superfund Site, Glendale, California Role: Hydrogeologist Scope/Description: This project involves the design, installation, testing, and sampling of a network of soil vapor monitoring wells, soil vapor extraction (SVE) wells and groundwater monitoring wells, in order to track, model and mitigate the extent of soil vapor contaminants and vapor intrusion in nearby properties.

Responsibilities included oversight of SVE well installation and testing, frequent soil vapor sampling, indoor and outdoor air sampling, and management of data. Site studies are being used to develop journal articles, related to comparison of SVE to subslab depressurization (SSD) as a mitigation technology.

Soil Removal and Well Abandonment, PG&E Kern Power Plant, Bakersfield, California Role: Lead Field Geologist Scope/Description: Project involved the removal of soil contaminated with oil and metals at a previously active power plant in Bakersfield, CA. Responsibilities included the on-site oversight of soil removal and categorization activities, confirmation soil sampling, and well abandonment activities. Inactive/dry wells were also decommissioned on-site to prevent further aquifer contamination. Completed successful site remediation at a publicly high-profile/sensitive site.

Adapted to unexpected field conditions related to historic operations. Acknowledged by the client for a strong safety culture.

Groundwater Monitoring and Remediation, Stringfellow Superfund Site, Riverside, California Role: Hydrogeologist Scope/Description: Field hydrogeologist for groundwater monitoring and remediation activities at an EPA Superfund Site located in Riverside, California. Led a detailed field effort to identify DNAPL contamination within fractured bedrock. Responsible for the logging and installation of groundwater monitoring wells, groundwater and soil sampling, and preparation of monitoring and installation reports.

Applied Research, PFAS

Environmental Services to Model the Leachability of PFAS Impacted Soil, AFCEC, Joint Base Elmendorf-Richardson (JBER), Anchorage, Alaska Role: Hydrogeologist Scope/Description: Developed a regulatory-approved methodology for modeling the potential leachability of ex-situ PFAS impacted soil with the goal of determining the maximum concentration of PFAS that may be present in the soil that will not result in an unacceptable risk to human and ecological receptors via the groundwater and surface water exposure pathways at JBER. The objective of this modeling effort was to determine whether a predictive model, which accounts for the unique chemical and physical properties of the PFAS constituents as well as site-specific conditions, can be employed to derive site-specific cleanup standards for PFAS-impacted sites that may differ from cleanup levels promulgated by the State of Alaska.

The anticipated modeling output resulted in generating a site-specific PFAS leach concentration from the ex-situ soils and concrete within the PFAS-impacted soil placement area that would remain protective of receptors (human and ecological) to PFAS-impacted groundwater and surface water.

PFAS Framework for Site Specific Source Strength and Leaching at AFFF Sources – ESTCP Project ER24-B1-8160, Multiple Sites, United States Role: Program Manager Scope/Description: The overall objective of this project was to develop a framework for evaluating site-specific soil-to-groundwater leaching and mass loading to facilitate site prioritization. This project assessed processes impacting fluxes of PFAS and the applicability of current vadose zone models for quantitative prediction of PFAS migration. Methods applied at two different source areas with differing depth-to-water, recharge rates, geology, and weather conditions to evaluate the broader applicability of the approach.

Water Resources, Water Quality

Environmental Production Well Design and Testing, Eastern Municipal Water District, Hemet, California Role: Hydrogeologist, Field Team Leader Scope/Description: Served as the field team leader and provided contractor oversight and inspection services to the District during drilling and testing of a groundwater production well to a depth of 1,500 feet, and assisted with the inspection and preparation of construction equipment. Contributed to the analysis and reporting of final construction results. Preliminary results indicated that the groundwater well produced >2,500 gpm, exceeding the district’s performance expectations.

Groundwater Development Feasibility Study, Eastern Municipal Water District, Perris, California Role: Hydrogeologist, Field Team Leader Scope/Description: Provided contractor oversight and inspection services to the District during drilling of an exploratory borehole to a depth of 695 feet to evaluate the suitability of the Site for future construction of a groundwater production well, and assisted with the preparation of a drilling and testing summary report. Based on evaluation of the drilling results and performance of other nearby District wells, concluded that the site appears favorable for a properly constructed well capable of achieving the District’s target minimum pumping rate of 650 gallons per minute or 1,000 acre-feet-per year

Feasibility Study and Discharge Permit, Former Smelter Facility, New Mexico Role: Hydrogeologist Scope/Description: This site included former smelter facilities, evaporation ponds, TDS treatment facilities and a network of monitoring wells. Responsibilities included monitoring and reporting of groundwater quality data in an effort to characterize and treat TDS and sulfate plumes, as a result of previous smelter operations.

Slope Stability Monitoring and Extraction Well Installation, Arizona Role: Hydrogeologist/Field Team Lead Scope/Description: This project involved the design and implementation of a network of extraction wells intended to monitor and improve stockpile stability via high-volume extraction of pregnant leachate solution. Responsibilities as the field team lead included technical oversight of the installations, testing and operation of piezometers and extraction wells on several stockpiles.

Area-wide Aquifer Protection Permit, Resolution Copper/Rio Tinto, Arizona Role: Hydrogeologist Scope/Description: Responsibilities included well siting, installation, aquifer testing and geochemical assessment of Point of Compliance Well for historical process pond. This included hydrogeological evaluation (i.e. gradients, depths of water, and constituents of concern of former facility) for proper well siting and design, and preparation and submittal of approved Well Installation Report.

Groundwater Exploratory Drilling, Arizona Role: Hydrologist Scope/Description: This project involved the proper siting, design and installation of four groundwater exploratory borings in support of a planned installation of new water supply wells, needed to support anticipated expansion of the plant. Responsibilities included the technical oversight and documentation of the drilling and testing of the exploratory borings.

PROFESSIONAL EXPERIENCE

• Geosyntec Consultants, Phoenix, AZ, 2025-Present

• BEM Systems, Inc., Denver, CO, Phoenix, AZ, 2020-2025

• CH2M Hill/Jacobs, Denver, CO, Santa Ana, CA, 2015-2020

• Golder, Tucson, AZ, 2012-2015

AWARDS AND RECOGNITIONS

• Top Young Professional (Mountain States and Southwest Region), Engineering News-Record

(ENR), 2025

• Business Achievement Award for Project Merit, Environmental Business Journal (EBJ), 2024, Project Title: Phase I Basewide PFAS Remedial Investigation, Buckley SFB, CO; Role: Project Manager for Prime Contractor

AFFILIATIONS

• Environmental Professionals of Arizona (EPAZ), 2024-Present

• Arizona Hydrological Society (AHS), 2013-2015, 2025-Present

• Geologic Society of America (GSA), 2014-Present

• American Institute of Professional Geologists (AIPG), 2024-Present

• Interstate Technology and Regulatory Council (ITRC) PFAS Team, 2020-Present

• National Ground Water Association (NGWA), 2024-Present

• Society of American Military Engineers (SAME), 2022-Present

INVITED PRESENTATIONS

• Society of American Military Engineers (SAME) Environmental Community of Interest (COI)

National Webinar, Presenter, 2025, Virtual

• Alaska Forum on the Environment, Presenter, 2025, Anchorage, AK

• Battelle Thirteenth International Conference on Remediation of Chlorinated and Recalcitrant

Compounds, Presenter, 2024, Denver, CO

• RemTEC & Emerging Contaminant Summit, Presenter, 2023, Westminster, CO

• DCHWS-West Symposium, Panelist, 2023, Denver, CO