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Your Environment. Your Health.

Xabier Arzuaga, Ph.D.

Superfund Research Program

Xabier Arzuaga, Ph.D., is a former SRP-funded graduate student and post-doctoral researcher from the University of Kentucky. He is now working as a risk assessor and toxicologist for the Integrated Risk Information System at the EPA.


Xabier graduated magna cum laude from the University of Puerto Rico in 1998 with a Bachelors of Science in Coastal Marine Biology. While there, he participated in an undergraduate exchange program, which brought him to the University of Kentucky (UK)., where he worked in an aquatic toxicology laboratory. This experience sparked his interest in toxicology and prompted his decision to return to Kentucky and join the Graduate Center for Toxicology after completing his undergraduate coursework.


While at UK, Xabier studied in the lab of Dr. Adria Elskus in the Department of Biological Sciences. He investigated the molecular and biochemical mechanisms of resistance to organic pollutant-induced toxicity in chronically contaminated killifish populations. His project was entitled "Mechanisms of resistance to halogenated and non-halogenated AHR ligands in chronically contaminated killifish populations." He completed his graduate research in 2004.


After finishing his graduate research, Xabier worked as a post-doctoral researcher in Dr. Bernhard Hennig's lab, on a project to understand the interactions between nutrition and persistent organic pollution exposure. Here, he was afforded many opportunities. He mentored undergraduate students and helped them design projects in cardiovascular and nutritional toxicology research. He says this helped him to gain confidence in his leadership skills and teamwork. The work also led to a greater appreciation of the role nutrition plays in health outcomes after pollutant exposure. Xabier's work in Dr. Hennig's lab helped him to appreciate the role that nutrition plays in the outcomes of pollution exposure. He now considers nutrition to be an important risk factor that should be taken into consideration. The appreciation for multiple factors and their impact on health outcomes has benefitted his work on risk assessment projects with the EPA.


Now that he has left academia, Arzuaga says that life is a little different. At the EPA, Arzuaga works on chemical assessments and preparation of toxicological reviews for the Integrated Risk Information System (IRIS) at the EPA. IRIS is EPA's electronic database containing information on human health effects that may result from exposure to various substances in the environment. The peer-reviewed information in IRIS is often used in combination with exposure information in a Superfund risk assessment to characterize the public health risks at hazardous waste sites. These risk characterizations form the basis of risk-based decision making, regulatory activities, and other risk management decisions designed to assess and protect public health. It is sometimes referred to as EPA's "gold standard" for toxicity information and is used world wide.


While not directly related to his academic work, he uses his knowledge of emerging technologies to help understand the mechanisms or modes of action by which exposure can lead to disease. "I now consider myself a consumer of the research data generated by research and academic institutions like the ones that form part of the SRP," he says.

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