Douglas Walker, PhD, is an Associate Professor in the Gangarosa Department of Environmental Health at Emory University and adjunct Assistant Professor at Utrecht University. He is an environmental engineer and analytical chemist with training in metabolomics and developing EWAS (exposome-wide association study) methodologies for environmental health and precision medicine research. He received his BS in Civil Engineering from the University of Massachusetts-Dartmouth and PhD in Environmental and Water Resources Engineering from Tufts University. At Emory University, Dr. Walker’s research focuses on continued development and application of advanced analytical strategies for measuring the occurrence, distribution and magnitude of previously unidentified environmental exposures and assisting in delineating the mechanisms underlying environment-related diseases in humans. The approaches he developed show it is possible to measure over 100,000 chemical signals that include exposure biomarkers, nutrients, dietary chemicals and associated biological response in a high-throughput and cost-effective manner, establishing a foundation for operationalizing the exposome framework for precision medicine. Ongoing research projects are now focused on using high-throughput exposome methods to establish disease-exposome atlases, and development of methods for measuring biomarkers of complex exposures of emerging concern, including microplastics, e-waste and polyfluorinated chemicals. Dr. Walker leads the Comprehensive Laboratory for Untargeted Exposome Science (CLUES), which was established to provide high-quality, untargeted screening of biological samples for nutrition, precision medicine and environmental health research.