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Alexandra Meyers
Senior Scientist

Alexandra Meyers

Senior Scientist (503) 943-3629 portland, OR

Ms. Alexandra Meyers is a human health risk assessor with 12 years of technical experience in the fields of environmental health science, toxicology, and exposure assessment. She has provided regulatory and litigation support for private clients and public agencies for contaminated sites throughout the U.S. Ms. Meyers has managed a wide variety of projects, including baseline human health risk assessments, screening and remedial goal evaluations, and vapor intrusion assessments. She has experience evaluating the potential health impacts associated with PFAS, PCBs, chlorinated solvents, dioxins and furans, PAHs, total petroleum hydrocarbons, and metals through multimedia exposures. Her extensive experience in leading human health risk assessments is focused on understanding the uncertainty and variability in exposure patterns and how that influences risk characterization results.

Human Health Risk Assessment

Groundwater Evaluation for Non-potable Purposes at a RCRA Landfill and Solid Waste Facility, Ohio Evaluated exposure to 1,4-dioxane in groundwater by offsite residential receptors assuming groundwater use for non-potable activities. Of the potential exposure routes, exposure through the ingestion of homegrown produce irrigated with well water posed the greatest potential risk. Calculated a health protective concentration for 1,4-dioxane in well water using EPA methods. The concentrations measured in groundwater were compared to site‑specific risk-based screening levels. The analysis demonstrated that groundwater was safe for all non-potable uses.
PFAS Groundwater Exposure at a Former Solvent and Waste Reprocessing Facility Superfund Site, New Jersey A baseline human health risk assessment was performed to assess potential risks to human health from hypothetical future use of groundwater by offsite residential receptors. PFAS chemicals were considered chemicals of potential concern (COPCs) in groundwater. It was not anticipated that site-related COPCs will come into contact with offsite residential receptors because the community is served by a municipal water supply. However, potential future exposure was assumed to support risk management decisions. The risk assessment considered the interim PFAS drinking water health advisories issued by EPA.
Feasibility Study for a Mine Tailings Site, Arizona A flotation mill historically processed ore material from the late 1870s through 1960s, resulting in the formation of two mine tailing piles. Performed a human health risk assessment to support an early response action and the remedy selection process for the feasibility study. The risk assessment evaluated exposure to lead, arsenic, and vanadium in surface soil of residential properties following soil removal actions.
Human Health Risk Assessments and Remedial Action Completion Reports for U.S. Department of Defense, Vandenberg Air Force Base, California A portfolio of 10 different project sites required a human health risk addendum evaluating unrestricted, residential site closure. Project sites were previously evaluated under a restricted, industrial site use scenario. Historical site data review was required to ensure risk calculations reflected current site conditions after the completion of previous remedial efforts. Also developed remedial action completion reports that indicated successful completion of the unrestricted site use requirements to allow for site closure.
Screening Level Assessment for a Manufactured Gas Plant, Montana Compared site data to Montana-specific criteria following the Montana Department of Environmental Quality’s Voluntary Cleanup and Redevelopment Act program. Prepared an environmental assessment documenting the results of the evaluation.
Risk-Based Cleanup Level Development for a Former Railyard, Vermont Derived site-specific risk-based cleanup levels for a railyard worker assuming potential exposure to PAHs and arsenic following the Vermont Department of Environmental Conservation’s Investigation and Remediation of Contaminated Properties Rule.
Technical Review of a Human Health Risk Assessment for a Former Battery Recycling Facility, California Reviewed a recently published human health risk assessment regarding data adequacy and evaluation, conceptual site model exposure assumptions, risk conclusions, and the associated uncertainties used to inform risk management decisions. Provided a technical report that summarized the findings based on the historical site activities that led to aerial deposition of lead in the surrounding community.
Technical Review of Human Health Risk Assessments and Background Risk Evaluation for a Former Pulp Mill Superfund Site, Montana Reviewed and submitted comments to EPA on the draft assessments highlighting the need for further evaluation of background risks distinctive of site-related risks. Supported the remedial investigation report by developing a revised risk assessment that compared site data to background concentrations to develop a focused list of chemicals of concern for remedial action.
Former Creosote Wood Treatment Facility Superfund Site, North Carolina Developed a human health risk assessment work plan in close collaboration with EPA and the North Carolina Department of Environmental Quality and executed the methodology in the subsequent human health risk assessments for two operable units. The evaluations focused on exposure to site soils by residential, commercial, and recreational receptors. COPCs for the site include dioxins and furans, PAHs, and pentachlorophenol.
Former Creosote Wood Treatment Facility RCRA Site, Missouri Evaluated exposures to chemicals detected in surface water by recreational users and unhoused individuals living adjacent to the site along the river. COPCs for the site include PAHs and pentachlorophenol.
Former Creosote Wood Treatment Facility Superfund Site, Virginia Finalized risk evaluation by responding to EPA comments on the draft human health risk assessment. The finalized assessment supported remedy selection for impacted groundwater. Drafted groundwater cleanup goals that met groundwater remedial action objectives. COPCs for site groundwater include PAHs.
Revised Cleanup Performance Standard for a Superfund Site, North Carolina Executed a human health risk assessment to reevaluate the EPA record of decision for a former Superfund site. The groundwater protection pathway was the basis for the performance standard requirement for groundwater site impacts from 1,2-dichloroethane. The revised risk assessment outlined a new performance standard based on potential inhalation of 1,2-dichloroethane groundwater vapors by an outdoor worker rather than a leaching to groundwater protection pathway, which is not reflective of human health exposure.
Site Redevelopment for a Rapid Transit Station, California Led a baseline and residual soil risk evaluation, which informed site managers of the current and long-term risks associated with site redevelopment. The residual evaluation developed exposure point concentrations based on soil samples that were expected to remain in place after site redevelopment. A risk ratio approach was used to estimate risks and noncancer hazards.
Human Health Risk Assessment for a Chemical Distribution Facility, Missouri The site owner voluntarily entered into an abatement order on consent with the Missouri Department of Natural Resources as part of the RI/FS. Site impacts were a result of historical site spills involving caustics, acids, chlorinated solvents, aliphatic solvents, ketones, alcohols, surfactants, heat transfer fluids, glycols, and acetates. Evaluated risks and hazards to site workers, offsite residents, and recreational receptors from exposures to soil, groundwater, surface water, and sediment at the site and adjoining property. Drafted health-based remedial goals.
Reporting Limit Evaluation for an Industrial Chemical Facility, Georgia Addressed the reporting limit of trimethylamine in soil and concrete samples collected at an active industrial chemical facility in support of a remedial action completion report. The reporting limit for trimethylamine was greater than the EPA regional screening level. Drafted a site-specific human health risk evaluation to assess exposure by an outdoor site worker to direct contact with soil and inhalation of vapors and fugitive dust based on exposure to the reporting limit for trimethylamine in soil.
Gasoline Retail Facilities Portfolio, Pennsylvania and District of Columbia Per the Pennsylvania Department of Environmental Protection’s Act 2 Land Recycling Program, executed multiple human health risk evaluations, including the development of site-specific standards resulting from potential exposure to petroleum hydrocarbons at former and current gasoline service stations. Future site redevelopment was considered, which required the evaluation of construction workers using the Virginia Department of Environmental Quality’s trench model to estimate concentrations of volatile organic compounds in air. For sites located within the District of Columbia, utilized the Risk-Based Correction Action Tier 1 and Tier 2 forms as required by the District. During the development of the initial reports, identified risk calculation errors in the automated forms and notified the Department of Energy and Environment, which subsequently updated the forms.

Vapor Intrusion

Daycare Facility in a Disadvantaged Community, Oakland, California A daycare center serving low-income, bilingual children was closed over concerns about potentially unsafe levels of volatile organic compounds in indoor air. The facility was to remain closed until it could be demonstrated that reoccupancy was safe. Developed site-specific indoor air and soil vapor screening levels based on the exposure patterns of the individuals occupying the facility. The maximum detected concentration of available site data was compared to the site-specific screening levels to determine current and hypothetical future vapor intrusion risks.
Multiuse Residential and Commercial Property, San Francisco, California A mixed use residential and commercial property historically operated as a dry-cleaning facility. Preliminary site data indicated exceedances above state regulatory screening values. Developed a site conceptual model to identify potential exposure pathways. Exposure to volatile organic compounds in indoor air was the primary pathway of concern. A vapor intrusion assessment was performed using a multiple-lines-of-evidence approach consistent with the California Department of Toxic Substances Control guidance.

Natural Resource Damage Assessment

Former Mine Superfund Site, Washington Conducted a comprehensive review of previous trustee and responsible party injury estimates for surface water and vegetation assessment areas. Implemented refinements to the service loss area estimates based on additional data considerations.

Litigation Support

Litigation Support Regarding PCB Exposures, Confidential Location Provided technical support regarding exposure assessment for several litigation projects related to PCBs identified in sediment, surface water bodies, fish tissue, and breast milk. The work includes analysis of PCB impacts as it relates to nursing infants, tribal receptors, anglers, and recreational users. This project is ongoing.
Litigation Support Regarding Volatile Chemicals in Ambient Air, Louisiana Provided project management and technical support regarding the fate and transport of volatile chemicals detected in ambient air samples generated by a municipal landfill. The work focused on identifying chemicals that warranted further investigation based on the toxicological endpoint exceedances of EPA health protective screening levels.