Heather Lynch, MPH, DABT

Principal, Toxicology, Health, and Ecological Science

Heather Lynch, MPH, DABT Principal, Toxicology, Health, and Ecological Science

Ms. Lynch is a Principal and board-certified toxicologist with 15 years of experience in toxicology, epidemiology, and human health risk assessment. Her areas of expertise include systematic review and weight-of-evidence (WoE) analyses, regulatory and site-based risk assessment, and the toxicity of heavy metals and persistent compounds, including polychlorinated biphenyls (PCBs) and per- and polyfluoroalkyl substances (PFAS). She also has extensive project experience pertaining to EPA programs and regulations such as the Integrated Risk Information System (IRIS) and the Toxic Substances Control Act (TSCA), including collating and analyzing consumer and occupational exposure data for submission to EPA. She previously worked as a contractor to several government agencies, managing large, chemical-specific risk assessments for the EPA National Center for Environmental Assessment (NCEA) and conducting toxicity reviews of substances petitioned for inclusion in the USDA National Organic Program. Ms. Lynch has published numerous original peer-reviewed articles on a range of substances and health effects. She is also a governor-appointed member of the Massachusetts Toxics Use Reduction Act Science Advisory Board. She recently served on the ad hoc Science Advisory Committee on Chemicals to conduct independent peer review of the draft TSCA risk evaluations for two chemicals.

Heather Lynch, MPH, DABT

Principal, Toxicology, Health, and Ecological Science

PFAS

State of the Science Review of Regulatory Standards and Human Serum PFAS Concentrations, United States Analyzed the regulatory framework for PFAS drinking water guidance and limits at the state and federal level and changes over time, provided a state-of-the science review of the toxicokinetics of PFAS in humans, interpreted measured serum concentration data, and evaluated modeling in an attempt to predict historical serum concentrations of PFAS.

Evaluation of Occupational Exposure to PFAS and Research Monitoring, United States Leading a project evaluating dermal exposure to PFAS through protective clothing, the relative contribution of such exposures to total exposure, and the potential for health risks to workers. This project also involves ongoing monitoring of agency and academic research on PFAS exposures and health effects in occupational populations.

PFAS and Emerging Contaminants Support for a Federal Agency, United States Managing ongoing contract with federal agency for scientific support related to emerging contaminants, with a focus on PFAS. Work includes technical reviews of PFAS toxicity value derivation, in-depth evaluation of human health effects of PFAS, strategic analysis, and development of recommendations and agency guidance. To date, developed a framework for the evaluation of agency assessments of PFAS and other emerging contaminants, authored white papers on the potential for and mechanisms of thyroid toxicity and immunotoxicity of PFAS, and performed technical reviews of recently developed state-level PFAS drinking water guidance values. Current projects include developing several manuscripts intended for submission to peer-reviewed journals.

Analysis of PFAS Toxicity and Ecological Transfer to Fish, Beef, and Edible Plants, Australia Managed several tasks for a human and ecological risk assessment of a PFAS-contaminated site in Western Australia, which is being assessed for reuse. Evaluated the uptake of three PFAS—perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), and perfluorohexane sulfonate (PFHxS)—in plants, fish, and livestock. Conducted comprehensive literature reviews and provided recommendations on transfer factors for PFAS uptake in the following pathways: soil to pasture grass consumed by cattle, soil to fruits and vegetables consumed as bush tucker, pasture grass to cattle (beef), and water/diet to three species of fish consumed by locals. Summarized the potential toxicity of PFOA, PFOS, and PFHxS for a variety of endpoints. Results were used to derive proposed remedial goals and actions at the site.

State of the Art Assessment of Carcinogenicity of PFOA and PFOS, United States Managed an assessment of the epidemiological and toxicological evidence of the carcinogenic potential of PFOA and PFOS, including prostate, bladder, breast, and kidney cancers. Developed a streamlined study quality evaluation system by refining the EPA methods for risk evaluations under TSCA. Integrated the key human, animal, and mechanistic studies while considering study quality, the consistency of findings within and across lines of evidence, and species concordance. Findings were summarized in a white paper.

Epidemiological and Regulatory Analysis of PFAS, United States In the context of several natural resource damage and toxic tort cases, conducted comprehensive reviews and syntheses of the available epidemiological literature of the potential associations between five different long- and short-chain PFAS and numerous human health endpoints, including cancer, liver disease, immunotoxicity, cardiovascular disease, and thyroid disease. These projects also included critical review of the bases for agency toxicity values for PFAS and the development of alternative toxicity values. As part of this effort, the team evaluated the toxicological significance of exposure to PFAS in drinking water relative to other sources (e.g., food and dust), and the scientific support for commonly used default exposure assumptions for intake of PFAS from each source.

Regulatory Support

TSCA Occupational Dermal and Inhalation Exposure Assessment, United States Supported two consortia of companies in the design and conduct of method validation and occupational dermal wipe sampling and inhalation sampling campaigns at numerous facilities across the United States; results were provided in reports to EPA. The dermal hand wipe method has been submitted for publication.

TSCA Consumer Product Emissions Testing, United States Supporting a consortium of companies in designing and carrying out product emissions tests and emission rate calculations for submission to EPA under a TSCA Section 4 test order.

TSCA Regulatory Support, United States Supported several industry trade groups in reviewing and commenting on EPA TSCA rulemaking and draft risk evaluation documents for the first 10 chemicals being evaluated using the new TSCA framework mandated by the 2016 Lautenberg Act.

Regulatory Comment Support, United States On behalf of several industry trade groups, reviewed and provided comments for submission on multiple national and international agency guidance documents (e.g., agency guidance on systematic review methodologies) and chemical risk evaluations (e.g., EPA’s IRIS and TSCA chemical assessments).

EPA NCEA, United States Managed and acted as primary author of human health risk assessment documents on priority chemicals for the Superfund Technical Support Center under a large contract with NCEA. Documents included summary of entire epidemiological and toxicological database for the substance, principal study selection rationale, and toxicity value derivation (inhalation and oral exposure).

EPA Office of Pesticide Programs, Antimicrobials Division, United States Assessed the quality and conduct of mammalian toxicology studies (primarily reproductive and developmental assays) for pesticide products and wrote data evaluation records for the active ingredient re-registration evaluation process.

USDA, United States Evaluated and wrote technical reports on substances petitioned for inclusion in the National List of Allowed and Prohibited Substances under the USDA National Organic Program. Reports included summaries of physical and chemical properties, potential for environmental contamination, and potential for human health effects.

Systematic Review

Systematic Review and Mode of Action Analysis for Propylene Dichloride, United States Led a systematic review of the noncancer and cancer effects of propylene dichloride, a chlorinated chemical prioritized for risk evaluation under TSCA. Following the EPA TSCA systematic review framework, evaluated and integrated the toxicological, epidemiological, and mechanistic evidence to develop hazard judgments. Also conducted an in-depth assessment of the mode of action of carcinogenicity. Both papers were published in the peer-reviewed literature.

Systematic Reviews of Ethylene Oxide and Talc, United States Led two comprehensive systematic reviews of the potential human carcinogenicity of ethylene oxide and talc using a hybrid method incorporating aspects of the frameworks developed for the EPA IRIS program and TSCA existing chemical programs, and by the Institute of Medicine and the National Toxicology Program Office of Health Assessment and Translation. Epidemiological, experimental animal, and mechanistic studies were evaluated for methodological quality and integrated to reach conclusions. Both reviews were submitted to journals for peer review and publication.

Community Exposure And Risk Analysis

Community Risk Evaluation, United States Leading a project evaluating the likelihood of health risks from facility fence line exposures to a chemical prioritized under TSCA. This project involves modeling air exposures to communities surrounding chemical facilities, developing health benchmarks, and evaluating the potential for unreasonable risk to humans living nearby.

Epidemiological Analysis of Health Effects from Solvents and Metals, Confidential Location Managing and serving as an expert consultant on a multiyear project involving numerous cases alleging exposure to metals and solvents from an industrial facility and cancer and noncancer health effects in workers and a nearby community. Project involves epidemiological general and specific causation analysis and critical review and interpretation of modeled exposure concentrations relative to exposures reported in the epidemiological and toxicological literature.

Evaluation of Neurocognitive Outcomes from Lead Exposure, Washington, DC Led a large project evaluating community exposure to lead in drinking water and the likelihood of cognitive outcomes in children, including IQ deficits, attention deficit hyperactivity disorder, and autism spectrum disorder.

Human Health Risk Assessment of Crude Oil Constituents, California, United States Conducted a risk assessment and causation analysis in a case alleging exposures to petroleum hydrocarbons and related contaminants at a former crude oil storage facility. The project involved general and property-specific risk assessments, a summary of the state of knowledge for several contaminants of concern, and a review and summary of toxicology and epidemiology literature for the contaminants.

Risk Assessment of Exposure to PCBs, Western United States Managed several litigation matters alleging human health effects from exposure to PCBs. Led a site-based risk assessment of multiple exposure pathways, a historical state of knowledge evaluation, and a comprehensive review of the toxicological and epidemiological literature on PCB exposure and cancer and noncancer health endpoints.

Toxicology

Pharmaceutical Leachables Assessment, United States Conducted hazard and risk assessments of two packaging options to determine the potential risks of exposure to compounds leaching from the packaging into a drug solution. This assessment involved an in-depth surrogate chemical assessment to address toxicity data gaps for several of the identified compounds.

Quantitative Risk Assessment of the Carcinogenicity of Inorganic Arsenic, United States Conducted a meta-regression analysis of epidemiological studies of the association between exposure to inorganic arsenic and cancer to derive a revised cancer potency factor. The work was used for a state agency report and published in the peer-reviewed literature.

Database Development and Quantitative Analysis of Arsenic in Food, United States Developed a large database of speciated arsenic measurements in food based on data from peer-reviewed literature and governmental surveys. Calculated average and maximum concentrations of arsenic species and the proportions of inorganic arsenic in a variety of commonly consumed foods. Published a peer-reviewed manuscript summarizing the data and discussing the implications of daily dietary intake of inorganic arsenic on overall human health risk.

Assessment of Exposure to Lead in Food, United States Reviewed lead toxicity literature and utilized blood lead modeling to predict blood lead levels and the likelihood of harm resulting from discontinuous exposures to naturally occurring lead in processed foods.

WoE Review of Ozone and Cardiovascular Disease, United States Applied a WoE approach to evaluate the totality of evidence from human and animal studies to evaluate the likelihood of associations between short- and long-term ambient ozone exposure and biomarkers of cardiovascular disease and apical cardiovascular disease. Three separate reviews were published in the peer-reviewed literature.

WoE Review of Particulate Matter and Biomarkers of Lung Cancer, United States Applied a WoE approach to evaluate recent evidence from four realms of research (controlled human exposure, epidemiology, animal, and in vitro) to determine whether the overall evidence supported one or more mechanisms of action by which particulate matter could cause lung cancer. This work culminated in a peer-reviewed publication.

Human Health Risk Assessment

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