Purdue University

Chemical Exposures

Modern society has seen an explosion in the commercial use of new chemical compounds. An estimated 80,000 industrial chemicals are in everyday use but only a small fraction of these have been tested for basic human health effects and we have even less data about which chemicals people are exposed to on a daily basis. Another challenge is evaluating how multiple chemical exposures and various social factors can interact to increase health risks. Much work remains to be done with historically recognized toxicants such as heavy metals and common industrial solvents. Many of these compounds are persistent in the environment, and bioaccumulative in the body, creating concerns about long-term and transgenerational health risks. Nations around the world face thousands of contaminated locations from previous industrial activity or waste disposal that must be remediated in some manner, many in low income or minority communities. The result is a combined set of difficult scientific and social challenges.

Purdue’s Approach

Our work in this area seeks to better understand the human and environmental consequences of chemical contaminants. We are linking traditional toxicology with cutting-edge biomedical engineering tools and methods to provide a clear mechanistic understanding of the toxicity of various chemical contaminants at sequential levels of biological organization (molecular-cellular-organ-organism). Here, the goal is to quickly and effectively predict adverse outcomes resulting from exposures to chemicals. Others are gathering data about multiple chemical exposures and studying the public health implications of these exposures in a variety of populations. Our researchers also focus on understanding the fate and transport of chemical contaminants in the environment, and they are developing novel remediation technologies. In addition, our faculty are working to develop less hazardous alternatives for some of these chemicals of concern, and to effectively communicate scientific risks with the public and local communities.

Projects

Development of PFAS-free fire extinguishing foam based on new siloxane-based surfactant formulations and time-released foam additives

PI: Carlos Martinez (Materials Eng)

Purdue Co-PIs: Jason Hoverman, Maria Sepulveda, Jeffery Youngblood

Sponsor: Department of Defense, SERDP

The objective of this project is to develop a PFAS-free foam formulation (PFAS-FFF) that satisfies the MilSpec requirements and can serve as a drop-in replacement. This will be accomplished by combining new custom-synthesized silicone surfactants that are formulated based on knowledge of their molecular properties to further lower surface tension with encapsulated foam additives designed to release at specific moments to enhance foam stability while mitigating issues these additives cause. Our approach is built on a recognition that no single material can replace PFAS– however, proper combinations of foam ingredients released at the times they are needed to transform the properties of the foam after application, may overcome the challenges of building a fluorine-free firefighting foam.

PFAS White Paper

PFOS-Induced Dopaminergic Neurodegeneration Across Animal Models

PI: Jason Cannon (Health Sci)

Co-PIs: Marisol Sepulveda (FNR), Amanda Hoskins, Tyler Hoskins

Funding: NIH

Per- and polyfluoroalkyl substances (PFAS) are widespread environmental contaminants that have been investigated as developmental toxicants, with little information on long-term neurotoxicity. Preliminary mechanistic and neuropathology data in nematode and amphibian models suggest that exposure to PFAS, especially perfluorooctane sulfonate (PFOS) induces selective dopaminergic neurotoxicity. This project addresses an important gap on how PFAS exposure leads to long-term neurological disease risk. The “big data” component of this work relates to the analysis of brain transcriptome responses of amphibians chronically exposed to PFOS in order to identify genes and/or pathways disrupted by PFAS toxicity. To do this, the team performed co-expression network delineation and differential expression analyses using a de novo transcriptome assembly. Resultant data will be critical in determining the neurodegeneration potential of PFOS and in identifying which pathogenic pathways directly correlate with neurodegeneration.

Evaluating PFAS Occurrence and Fate in Rural Water Supplies and Agricultural Operations to Inform Management Strategies

PI: Linda Lee (AGRO)

Funding: EPA

Lee’s team will study the occurrence of PFAS and their concentrations in private drinking wells and water resource recovery facilities in rural communities in Indiana, Pennsylvania, and Virginia. The team will also research the relative contribution of PFAS from land-application wastewater and biosolids to rural water supplies. This work will identify landscape, hydrologic, and soil characteristics that are most appropriate for receiving biosolids or treated wastewater with minimal impact to water and crop resources.

PFAS White Paper

Assessment of Cured-In-Place Pipe Installation Emissions and Toxicity

PI: Jonathan Shannahan (HSCI)

Co-PIs: Brandon Boor (CIVIL), Andrew Whelton (CIVIL, EEE)

Nationwide and globally there is a growing need for repair of sanitary sewer, storm sewer, and drinking water pipes. The cured-in-place pipe (CIPP) method has become the most popular method to repair deteriorated water pipes. This process involves the onsite chemical fabrication of a polymer composite plastic pipe within the damaged pipe. Recent evidence has indicated public health incidences related to chemical air contamination emitted from CIPP sites. The central objective of this proposal is to investigate CIPP operational procedures that influence emissions and toxicity. Our hypothesis is that commonly utilized resin materials (styrene or non-styrene based) produce distinct emissions during the curing process that result in differential toxicity following inhalation. To address our hypothesis, we propose the following specific aims:

  1. Evaluation of differential CIPP-related emission profiles due to resin materials, and
  2. Assessment of adverse health effects following inhalation exposure to CIPP-emissions.

In Aim 1, tubing impregnated with either styrene or non-styrene based resin will be thermally cured within the curing chamber and emissions will be characterized via photoionization detectors and gas chromatography-mass spectrometry. In Aim 2, male and female mice will be exposed to filtered air (controls), CIPP emissions, or styrene-only and examined for pulmonary and liver toxicity (inflammation and oxidative stress) as well as alterations in serum metabolites. At the completion of this project, it is our expectation that we will have begun to elucidate the relationship between CIPP resin materials, emission profiles, and toxicity. Ultimately, the long-term impact of this research will be the potential to regulate risk, related to CIPP emission exposures by the general public through defining safe operational procedures.

An award was received from US EPA for $15,000 to Shannahan and Whelton titled “Developing Practices for Responding to Chemical Incidents”. This project will allow formation of a workgroup consisting of health officials and Cured-in-place-pipe (CIPP) experts to identify best public health practices and response efforts. Individuals in the workgroup will participate in structured and focused discussions on topics meant to formulate best practices to prevent and respond to CIPP air incidents.

More information here.

Development of Amphibian Poly/perfluoroalkyl Acids (PFAASs) Toxicity Reference Values for use in Ecological Risk Assessment at Aqueous Film-Forming Foam Sites

PI: Marisol Sepúlveda (FNR)

Co-PIs: Jason Hoverman (FNR), Linda Lee (AGRO)

Funding: SERDP

The use of aqueous film-forming foams containing poly- and perfluoroalkyl substances (PFASs) at Defense Environmental Restoration Program (DERP) fire, crash, and training sites has potentially contributed to PFAS contamination of soil, water, and sediment. The overall objective of this SERDP effort is to develop amphibian toxicity reference values (TRVs) to support ecological risk assessment of PFASs in contaminated DERP sites. Such data are needed for supporting cleanup and/or exposure mitigation decisions. Specifically, the project team aims to:

1) develop toxicity reference values for perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) in amphibians, and

2) determine the potency of two additional PFASs in amphibians: 6:2 fluorotelomer sulfonate and perfluorohexane sulfonate.

More information

PFAS White Paper

Quantifying the Distribution, Movement, and Ecological Risk of Per-/Polyfluoroalkyl Substances (PFAS) in an AFFF-Impacted Wetland Ecosystem

PI: Jason Hoverman (FNR)

Co-PIs: Linda Lee (AGRO), Marisol Sepulveda (FNR)

Funding: MI DNR

Aqueous film forming foams (AFFFs) containing PFAS have been extensively used at Department of Defense Fire/Crash/Training sites since the 1970s. This widespread usage, combined with their high resistance to degradation, has contributed to contamination of soils, water, and sediment at these sites and surrounding areas. Given their propensity to bioaccumulate, there are increasing concerns over the potential movement of PFAS within food webs and health risks to wildlife and humans. Ecological risk characterization is currently limited by the lack of sufficient ecotoxicological and bioaccumulation/biomagnification data for the wide diversity of species and PFAS mixtures found at contaminated sites.

PI Jason Hoverman (FNR) and postdoctoral researcher Wes Flynn (FNR) are leading this project to examine levels of PFAS contamination in Clark’s Marsh Wildlife Area This research expands upon the team’s related work that assesses developmental effects and bioaccumulation of PFAS via aquatic, dietary, and dermal exposure routes in amphibian larvae and adults using controlled laboratory and semi-realistic wetland mesocosms. The core outcome will be an improved understanding of bioavailability, bioaccumulation, and biomagnification of PFAS within wetland food webs. The team’s empirical results will enable further refinement of PFAS ecological exposure models.

PFAS White Paper

The Relative Toxicities of Current Use Aqueous Film Forming Foams and Next Generation Alternatives to Aquatic Species for Informing Risk Assessment

PI: Jason Hoverman (FNR)

Co-PIs: Linda Lee (AGRO), Marisol Sepulveda (FNR)

Funding: DOD

Given the widespread contamination, persistence, and environmental impacts associated with the use of aqueous film forming foams (AFFF) containing per- and polyfluoroalkyl substances (PFAS), there is a need to develop PFAS-free foam alternatives to replace old technologies in fire-suppression operations. However, before the selection and implementation of fluorine-free foam alternatives, research must address their potential environmental impacts.  In 2020, we were funded by SERDP to assess the relative toxicity of AFFF alternatives to aquatic species (ER20-1537).  For this project, we are conducting controlled laboratory experiments with zooplankton (water fleas, Daphnia magna), fish (fathead minnows, Pimephales promelas), and larval amphibians.  We are addressing the following questions:

  1. Are AFFF alternatives toxic to common aquatic species in North America (i.e. zooplankton, fish, and amphibians)?
  2. If AFFF alternatives are toxic, what is their relative toxicity to our three focal species?
  3. How does the toxicity of AFFF alternatives compare to the short-chain AFFF formulations currently in use by the Department of Defense (DoD)?
  4. Do AFFF alternatives bioaccumulate within aquatic species and, if so, what is the distribution of bioconcentration factors across our focal species?

Because little is known regarding the toxicity of PFAS-free AFFF formulations, the first phase of our project focused on acute toxicity trials.  In brief, the acute toxicity trials were conducted across a broad range of concentrations of the formulations and survival was monitored daily for 48 hours.  The data was then used to calculate the 48-hour LC10, LC50, and LC90 values. These studies determined the general toxicity of the formulations and were used to inform our selection of concentrations for our chronic exposure experiments.

In the second phase of the project, we will conduct chronic toxicity studies to determine the long-term effects of PFAS-free AFFF alternatives on ecologically relevant endpoints (e.g., growth, development, survival; see table) in each species. The experimental designs will consist of a control and each of the formulations at 5 concentrations.  For the 5 concentrations, we will use the USEPA dilution factors (5, 10, 100, 1000) of the calculated LC5048-HR values, in addition to the LC1048-HR, obtained through the acute toxicity trials.

More information

PFAS White Paper

Groundwater Contamination and Health Equity in a Deindustrialized Midwestern Community

Co-PIs: Sa Liu (HSCI), Jennifer Johnson (ANTH)

Funding: RWJF

This project examines environmental contamination and community health in the deindustrialized Midwest. Together we focus on one community in Indiana where residents continue to source their water from a groundwater body long contaminated by multiple toxic chemical plumes released by former industries. While this community is exceptional in many ways, it is increasingly reflective of broader regional trends, especially with respect to rising rates of cancer and poverty. By engaging multiple methodological approaches and a range of community members we will pursue three intersecting research questions: How do differentially-situated community members perceive and respond to information about the risks that environmental contamination poses to their health; What are the levels of risk associated with exposure to different sources of the same environmental contaminant; and do (and if so how do) levels of risk differ in relation to socioeconomic and environmental factors, such as income, education, family size, and primary water source?

More information

Rural Environmental Health Assessment and Neighborhood-Specific Public Health Plan for Hartford City Using a Community-Engaged Approach

Co-PIs: Ellen Wells (HSCI)

Funding: NIH-CTSI

This project addresses rural health inequities related to the impact of environmental contamination in Hartford City, Indiana (population: 5,831). Environmental factors are an important, yet understudied, contributor to multiple diseases. Environmental health inequities often exacerbate overall health inequity. Community members suspect contamination from a steel recycling facility in the low-income Commercial-Main neighborhood may affect their health, but currently lack definitive data. The team will assess concentrations of heavy metals in environmental samples (air, soil, dust) and personal samples (urine, toenails) collected from adult community members living in Commercial-Main (n=50) and in comparable neighborhoods (n=50). A comprehensive health survey will be completed by 300 adults; the survey will collect data on health status and risk factors. The team will engage stakeholders throughout the project. The team anticipates that exposure will be higher and health outcomes will be worse in Commercial-Main. Based on findings, the team will work with the community to develop a public health plan to reduce exposure and improve health equity. Anticipated outcomes include determination of whether heavy metal exposures are higher in samples from Commercial-Main; characterization of health outcomes of most concern to the community as well as factors correlated with these outcomes; and development of actions that can be taken to address environmental health inequities.

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SRA CONVENER

Jennifer Freeman
Health Sciences

Jennifer Freeman is a professor of toxicology in the School of Health Sciences and Interim Director of the Center for the Environment. Freeman’s research interests are in molecular and environmental toxicology, cytogenetics, genomics and epigenomics. Current research efforts in the Freeman laboratory are defining the underlying genetic and epigenetic mechanisms of developmental exposure to environmental chemicals, including pesticides and metals, with a focus on drinking water contaminants.  Freeman received her Ph.D. in environmental toxicology and molecular cytogenetics from the University of Illinois at Urbana-Champaign and was a postdoctoral fellow at Harvard Medical School and Brigham and Women’s Hospital, Boston, Massachusetts.