EPA Development of Computational Approaches Predicting Thyroid Systems Disruption in Aquatic Species

Organization

U.S. Environmental Protection Agency (EPA)

EPA-OCSPP-

10/9/2026 3:00:00 PM Eastern Time Zone

• Applications may be reviewed on a rolling-basis and this posting could close before the deadline.

A research opportunity is currently available at the Environmental Protection Agency (EPA), Great Lakes Coastal Environmental Science Laboratory, located in Duluth, Minnesota.

The mission of EPA is to protect human health and the environment. EPA works to ensure that:
Americans have clean air, land and water; national efforts to reduce environmental risks are based on the best available scientific information; federal laws protecting human health and the environment are administered and enforced fairly, effectively and as Congress intended;
Environmental stewardship is integral to U.S. policies concerning natural resources, human health, economic growth, energy, transportation, agriculture, industry, and international trade, and these factors are similarly considered in establishing environmental policy;
All parts of society have access to accurate information sufficient to effectively participate in managing human health and environmental risks;
Contaminated lands and toxic sites are cleaned up; and chemicals in the marketplace are reviewed for safety.

The US EPA is mandated to address the endocrine disrupting potential of thousands of chemicals. For the majority of these chemicals there is a lack of information regarding whether they have the potential to cause adverse effects from impacts on thyroid hormone status. Understanding the important targets within the network of processes involved in maintaining normal functioning thyroid hormone levels, and what approaches to best assess activity at those targets are critical to developing a comprehensive approach to evaluating thyroid hormone disrupting potential of large numbers of chemicals.

Recently, a number of thyroid-related in vitro high-throughput screening (HTS) assays have been developed to broaden assay coverage for molecular targets potentially leading to thyroid disruption and were implemented to screen US EPA’s Tox Cast Phase 1, 2 and E1K chemical libraries. This battery of thyroid-related in vitro HTS assays can be employed to rapidly assess potential interference with these targets.

However, this screening approach leaves uncertainties regarding the meaning of in vitro activity data as it relates to in vivo adverse outcomes. Part of this research effort aims to develop a translational process that integrates relevant information, models, and data streams to provide richer context to interpret in vitro results related to thyroid disruption. As part of the translational process, this fellowship will focus on the development of a bio-assay to quantitative monitor thyroid hormone synthesis as a complimentary assay to existing in vitro thyroid-related assays.

Assay development will be followed by the analysis of canonical and suspected thyroid disrupting chemicals to understand whether, or how, in vitro activity of chemicals translates to in vivo outcomes. Additionally, this research will employ existing computational tools such as the octanol-water partition coefficient (logKow) and quantitative structure-activity relationships (QSAR) models to provide deeper interpretation of in vitro data and further prioritize chemicals most likely to impact thyroid function in aquatic systems.

The translational principles employed will have much broader applicability across Tox Cast HTS assays and aquatic vertebrates.

• Learn how innovative in vitro to in vivo extrapolation and reverse toxicokinetic approaches are used to translate effect concentrations…