Superfund Research Program
Congratulations to the 2022 winners of the K.C. Donnelly Externship Award!
Laura Dean, Ph.D., is a postdoctoral research scholar with the University of Iowa (UI) Superfund Research Program (SRP) Center under the mentorship of Hans-Joachim Lehmler, Ph.D. For her externship, Dean will work with Lei Guo, Ph.D., at the National Center for Toxicology Research — a branch of the Food and Drug Administration — in Jefferson, Arkansas.
Dean studies how the body breaks down environmental pollutants called polychlorinated biphenyls (PCBs). So far, her work has focused on PCB metabolism in the brain cells of young rats. For her externship, Dean will use human-derived liver cell cultures, developed by Guo, to study the role of cytochrome P450 proteins — which process foreign chemicals — in metabolizing airborne PCBs. The research could inform future studies that assess PCB breakdown by cytochrome P450s in the brain.
"My goal is to become an analytical and forensic toxicologist," Dean said. "I'm excited to learn new techniques from Dr. Guo and experience what it's like to work in a government agency lab."
Rebecca Dickman is a doctoral candidate at the State University of New York at Buffalo, where she works with Diana Aga, Ph.D., an SRP individual research project grantee. Dickman's externship will take place remotely, with collaborators Jon Sobus, Ph.D., and James McCord, Ph.D., from the Environmental Protection Agency (EPA) in Research Triangle Park, North Carolina.
For her graduate work, Dickman develops ways to detect and identify unknown per- and polyfluoroalkyl substances (PFAS) in environmental samples. Those methods often employ mass spectrometry — a technique for analyzing molecules based on their mass and charge — and liquid chromatography, which separates molecules based on their mobility through a medium. With her EPA mentors, Dickman will evaluate how the presence of other compounds affect PFAS behavior during chemical analysis. That data will inform a preliminary computer model designed to quantify unknown PFAS in complex mixtures. Ultimately, such a model could be used to measure the efficacy of remediation efforts to break down PFAS in environmental samples.
"Through this opportunity, I hope to sharpen my skills in data science and computational chemistry while improving techniques for identification and quantification of unknown PFAS," Dickman said. "In addition, this externship will give me a chance to gain experience in the public sector, which has been a major goal of mine throughout my academic training."
Avinash Kumar, Ph.D., is a post-doctoral researcher with the Louisiana State University SRP Center in the lab of center director Stephania Cormier, Ph.D. For his externship, Kumar will work with Ilona Jaspers, Ph.D., at the University of North Carolina at Chapel Hill SRP Center.
Kumar's current research looks at the connection between respiratory tract infections in infant mice and exposure to combustion byproducts known as environmentally persistent free radicals (EPFRs). Through his externship, Kumar will learn new techniques to analyze microorganisms and metabolic byproducts in EPFR-exposed mice. The aim is to better understand how an imbalance in microbial communities can affect the severity of influenza stemming from EPFR exposure.
"Growing up in a rural area, I witnessed a lack of facilities and treatment options," Kumar said. "I feel obligated to improve understanding of common but rampant pathologies like influenza infection, nutritional disorders, inflammation, and metabolic disorders."
Francisco Léniz is a doctoral candidate under the mentorship of Dibakar Bhattacharyya, Ph.D., at the University of Kentucky SRP Center. He will complete his externship with Yale University's Julie Zimmerman, Ph.D., a project leader with the Harvard University SRP Center.
Léniz will build on his graduate work studying water purification technologies. Earlier, he focused on creating an artificial membrane to filter PFAS from water. During his externship, he will learn about technologies for — and obstacles to — separating arsenic from water, with the goal of developing a more efficient platform for treating water containing the toxic element and other substances of concern.
"Applying the knowledge, perspectives, and experiences I've gained over the past four years to the K.C. Donnelly externship is what I have been waiting for," Léniz said. "This opportunity will help me enhance my skills as a researcher and expand my collaborative work to ultimately provide innovative solutions to environmental health problems."
Martine Mathieu is a doctoral candidate at North Carolina State University studying under Jennifer Richmond-Bryant, Ph.D., a project leader with the Louisiana State University (LSU) SRP Center. For her externship, Mathieu will work with Keri Hornbuckle, Ph.D., and Andreas Martinez, Ph.D., at the UI SRP Center, which Hornbuckle also directs.
Mathieu uses spatial and statistical modeling to study particulate matter, such as EPFRs, emanating from a Superfund site in Louisiana. At UI, she will learn how to use AERMOD, a software program that predicts air pollutant dispersion from its source. As part of her externship, Mathieu will work with UI SRP Center trainee Alexis Slade to learn about airborne PCB contamination at a Superfund site in Oregon. Together they will install air quality samplers at both Superfund sites. Ultimately, Mathieu plans to integrate various air quality data into a model that estimates pollutant exposure levels based on chemical concentrations.
"The knowledge I gain will enhance my understanding of EPFR toxicity and lung disease," Mathieu said. "I also look forward to broadening my professional network and helping the LSU SRC and UI SRP centers collaborate."
Charlotte Wirth is a doctoral candidate at the Harvard University SRP Center in the lab of Quan Lu, Ph.D. Her externship will entail research at the University of California, Berkeley SRP Center, with guidance from Christopher Chang, Ph.D.
Wirth studies how lead exposure affects immune cells called microglia. For her externship, she will apply a molecular labeling technique to a culture of microglia to see whether lead exposure increases cellular stress. She hypothesizes that cellular stress may trigger the release of molecular signals from microglia that might contribute to inflammation and neurotoxicity associated with lead exposure. Her findings could help inform the identification of biomarkers, or biological signs, of cognitive disorders.
"As a tutor or teaching assistant for eight classes in my undergraduate career, I developed a passion for inspiring scientific interest in others," Wirth said. "I hope to apply what I learn using the chemical labeling technique to my thesis work and to training others."
Melissa Woodward is a doctoral candidate at the University of Rhode Island SRP Center, where she works with center director Rainer Lohmann, Ph.D. Her externship will take place at the Duke University SRP Center, in the lab of center director Heather Stapleton, Ph.D.
For her graduate work, Woodward develops sampling devices from resin-filled plastic tubes designed to absorb PFAS in outdoor and indoor air. She is also devising a method to measure PFAS in dust. At Duke, Woodward will learn a new analytical technique for identifying PFAS in field samples. She will also investigate whether her samplers can measure other air pollutants, such as organophosphate esters.
"My goal is to create tools that can measure a wide scope of pollutants in different environmental situations," Woodward said. "By learning where they are, we can better understand human and animal exposure to these contaminants."