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Uranium, a naturally occurring element used in military and industrial applications, accumulates in the skeletal system of animals and humans. Evidence from animal and in-vitro studies demonstrates that uranium exposure is associated with alterations in normal bone functions. The...

Standard ecological risk assessment practices often rely on larval and juvenile fish toxicity data as representative of the amphibian aquatic stage. Although empirical evidence suggests fish early life stage tests frequently are sufficiently sensitive to protect larval amphibians...

Accounting for intraspecific and interspecific competition when assessing the effects of chemical and nonchemical stressors is an important uncertainty in ecological risk assessments. We developed novel projection of interspecific competition (PIC) matrices that allow for analysi...

The Clean Air Act establishes a two-stage regulatory process for addressing emissions of hazardous air pollutants (HAPs) from stationary sources. In the first stage, the Act requires the EPA to develop technology-based standards for categories of industrial sources. We have lar...

Protecting a diversity of species from the adverse effects of chemicals is a significant environmental challenge. Information on the effects of chemicals on species is either limited or lacking entirely, making management and mitigation of environmental contaminants difficult. Th...

The six PFAS we have studied (PFOA, GenX, PFMOAA, PFOS, NBP2, PFHxS) produced multiple common effects across all compounds, however the compounds were not toxicologically identical.  Effects common across all compounds included reduced pup and maternal bodyweights, reduced p...

1.    Introduction A growing number of pollutants are reported to negatively affect the hypothalamus-pituitary-thyroid (HPT) axis. Resorcinol is currently under consideration as a substance of very high concern in the European Union. It is used for a variety of pur...

Causal structural models are used to capture knowledge of a problem domain through framing potential events as random variables and connections as causal arcs. Moreover, the properties of causal structural models foster additional insights on causal and inferential interactions a...

As Ecological risk assessments (ERA) move beyond organism-based determinations towards probabilistic population-level assessments, model complexity must be evaluated against the goals of the assessment, the information available to parameterize components with minimal dependence ...

Changes in size at and time to metamorphosis indicate developmental effects in amphibians that could result in population-level impacts. Current risk assessment practice uses early life stage fish data when data for larval amphibians are not available. While fish are sufficiently...

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Terrestrial organisms and ecosystems are being exposed to new and rapidly changing combinations of solar UV radiation and other environmental factors because of ongoing changes in stratospheric ozone and climate. In this Quadrennial Assessment, we examine the interactive effects ...

Background and Purpose: Time series data for environmentally relevant chemicals in body fluids and tissues after an exposure is rarely made available despite their importance for risk assessment. Further, access to in vivo data is crucial for chemical safety evaluation estimate...

In recent years several OECD test guidelines have been updated and some will be updated shortly with the requirement to measure thyroid hormone levels in the blood of mammalian laboratory species. There is, however, an imperative need for clarification and guidance regarding the ...

Aquatic ecosystem resilience to wildfire can vary widely depending on the characteristics of fire and the spatial context of where a fire takes place. Researchers at EPA’s Office of Research and Development are collaborating with the US Forest Service, and Oregon State Univ...

Within the field of health risk assessment, it is essential that evaluations of reliability or validity of toxicity data are conducted with structure and transparency. To this end, different tools for evaluating toxicity studies have been developed by different groups and organiz...

Physiologically based pharmacokinetic (PBPK) models are commonly used in risk assessments to perform inter- and intraspecies extrapolations as well as to extrapolate between different dosing scenarios; however, they must first undergo quality assurance review, which can be a time...

The Quantitative Structure Use Relationship (QSUR) Summit, held on November 2–4, 2022, focused on advancing the development, refinement, and use of QSURs to support chemical substance prioritization and risk assessment and mitigation. QSURs utilize chemical structures to pr...

This study investigated the presence and human hazards associated with pesticides and other anthropogenic chemicals identified in kale grown in urban and rural environments. Pesticides and related compounds (i.e., surfactants and metabolites) in kale samples were evaluated using ...

Regulatory authorities aim to organize substances into groups to facilitate prioritization within hazard and risk assessment processes. Often, such chemical groupings are not explicitly defined by structural rules or physicochemical property information. This is largely due to ho...

This Subproduct is a slide deck for an invited presentation at the Georgetown University Center for PFAS and Cancer (CPAC) Joint Virtual Symposium.  Slide deck presents the results of our group's PFAS developmental toxicity mixture studies.  This work demonstrates the d...

1-Bromopropane (CASRN 106-94-5): or 1-BP is a volatile organic chemical that is considered moderately persistent in the environment but does not have the potential to bioaccumulate in fish or other animals. The majority of the 1-BP production volume (~ 47%) is used as a vapor deg...

Trichloroethylene (TCE) has a wide-range of uses in consumer and commercial products and in industry. An estimated 84% of TCE's annual production volume is used as an intermediate in the manufacture of the hydrofluorocarbon HFC-134a. Another 15% of TCE production volume is used a...

N-methylpyrrolidone (NMP), also called N-methyl-2-pyrrolidone, or 1-methyl-2-pyrrolidone, is a chemical that is widely used during the manufacture and production of polymers, pharmaceuticals, agrichemicals and petroleum products. Information from the 2016 Chemical Data Reporting ...

EPA evaluated the following categories of conditions of use of chrysotile asbestos in this draft risk evaluation: Manufacturing; processing; distribution in commerce; occupational and consumer uses; and disposal.