Purdue researchers monitor the human health risks of PFAS exposure

Written By: Stacey Mickelbart, smickelb@purdue.edu

The West Calumet Housing Complex was built in East Chicago in Northwest Indiana in the early 1970s, on the site of former plants that smelted, refined and salvaged lead. Even then, officials were unsure if the land previously zoned for heavy industry could be safe for residential housing. Research in the 1980s and ’90s revealed many of the 90% Black or Latino residents, especially children, had elevated blood lead levels. In 2009, the complex was declared a Superfund site that is severely polluted and was added to the Environmental Protection Agency’s (EPA) National Priorities List. In 2016, approximately 1,100 residents were told they should move out of the complex for their safety — initially with only 60 days’ notice.

The resulting media coverage and public and community meetings attracted Ellen Wells’ attention. Wells, a professor in the Purdue University College of Health and Human Sciences’ Department of Public Health and School of Health Sciences, studies environmental epidemiology, or how environmental issues impact the distribution, patterns and effects of disease in a population.

“I attended some of the meetings to get more information about what was going on because I’ve had a long-term interest in understanding health effects of lead exposure,” Wells said.

She began working with fellow scientists and community members in northern Lake County to examine air, water and road dust samples for a variety of contaminants, including heavy metals. Now, at the request of members of the Northern Lake County Environmental Partnership, she’s added PFAS to that list.

Investigating human exposure to PFAS

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are commonly known as “forever chemicals” because they persist in the environment and are difficult to break down. 

They are used to manufacture a wide variety of industrial and consumer products, such as firefighting foams, stain-repellent coatings on carpets and furniture, nonstick pans and cosmetics. They bioaccumulate, or build up, in the body and are found in our blood and urine, as well as the environment — including animals, water, air and soil. PFAS are increasingly recognized as a widespread hazard to human and environmental health.

“I’m interested in any group that we would consider vulnerable for some reason or other,” Wells said.

At-risk populations include pregnant mothers, children, the elderly and specific occupational populations.

“Some people are more vulnerable because of their biology, and others are more vulnerable because they’re in places with higher contamination,” Well said.

She meets with the advisory board at least four times a year to learn which environmental contamination issues they’re concerned about, adding them to her study so she’ll be better equipped to answer questions from community members in addition to her own scientific inquiries. The group of researchers working together includes Julie Peller and Christopher Iceman, professors of chemistry at Valparaiso University; Graham Peaslee, professor emeritus of nuclear physics at the University of Notre Dame; Ken Brown, professor of chemistry at Hope College; and Jodi Allen, associate professor of nursing at Purdue University Northwest.

“One of the risks of that combination of contaminants is that we know they could affect neurological health,” Wells said.

Neurological disorders that affect the brain, spinal cord and nerves might affect a person’s behavior, memory, ability to learn, and communication and social skills.

In addition to testing environmental samples, Wells and her team ask participants in the study about their health history, including interactions with hobbies or occupations that might have exposed them to environmental contamination. With expertise from Bridgette Kelleher, professor and director of digital health in the Indiana University Institute for Human Health and Wellbeing and adjunct professor of psychological sciences at Purdue, and Dan Foti, professor of psychological sciences at Purdue, they conduct neurological function tests with questions on cognition, memory and emotional regulation.  They also collect biomarkers such as hair, saliva and blood.

“Measuring how much has actually gotten into someone’s body gives a much better estimate of the extent to which environmental contaminants are affecting a given person,” Wells said.

Analyzing from many angles

Wells shares her samples with collaborators in Purdue’s Institute for a Sustainable Future on the PFAS strategic research team. Their labs have techniques to measure contaminants she can’t. Her soil samples are tested by Linda Lee, distinguished professor of agronomy and sustainability engineering and environmental engineering and assistant dean of agricultural research and graduate education, whose liquid chromatography-tandem mass spectrometer can detect PFAS in parts per billion to parts per trillion.

Wells shares saliva samples with Jennifer Freeman, professor of health sciences and assistant vice president for research development in the Office of Research, for epigenetic analyses, examining how behaviors and environment can cause changes in gene function.

Working with Freeman is essential. Studying human health is complex because humans themselves are so complex. Where the lab is a controlled environment, humans interact with multiple contaminants and experience factors that might impact results, such as stress. So, while human studies can provide a more comprehensive understanding of all the conditions influencing our health, they can make it difficult to measure the impact of a single contaminant — information necessary to develop effective policy and regulations for contaminants.

Translating from model species to humans

“I work with the zebrafish model system because it helps to increase our confidence in translatability to human studies,” said Freeman. “If we see similar changes happening in different model systems, then it’s more likely we’re also going to see those changes in humans.”

Zebrafish are a common model in developmental biology, so Freeman uses them to understand the types of neurotoxicity we might see following PFAS exposure.

PFAS have been found to cross the blood-brain barrier in multiple species, so they can accumulate in brain tissue. Freeman studies whether observed changes in the brain related to PFAS can lead to damage of the neurons that help receive, process and transmit information.

“We’re concerned about PFAS exposure in children because if it’s affecting their brain development, we might see changes in their learning ability and different behavioral outcomes related to hyperactivity,” Freeman said.

Freeman aligns her exposures and collaborative projects with Chongli Yuan, Charles Davidson Professor of Chemical Engineering, who maintains a human neuronal cell line, “so that work can have a direct translation between the whole animal model and the human cells, so we can compare them.”

Protecting public health

 “There was more variety and quantity of different types of PFAS than I was initially expecting,” Wells said, with the analysis of about half her most recent soil samples complete. “We were expecting that a lot of this community’s exposure to PFAS was going to come from consumer products. So, the fact that we found measurable quantities in the soil of not only legacy PFAS but also some of the newer PFAS is noticeable.”

Lee, whose collaborative research includes engineering partners who work to filter PFAS through absorption (taking it in) or adsorption (causing PFAS to stick to the surface of another material), would like to see changes in how PFAS are handled in manufacturing.

“First, clean or pre-treat PFAS as a byproduct, no matter what. Second, require and encourage transparency so that when manufacturers find something, they’re able to come forward,” she said, citing previous voluntary cleanup programs for gas and coal plant sites. “Third, the EPA ought to be conducting a certain subset of sampling every year.”

Improving public health continues to drive Wells.

“Interacting with the community gives me a much fuller picture of what they’re experiencing and what they think the priorities are,” she said. “We work with a lot of really supportive and appreciative community members, so when I talk with them, they remind me of how important it is to keep trying.

“Members of vulnerable populations tend to have the most severe impacts from contaminants, so by protecting those populations, the hope is that we can protect everybody.”