Douglas Walker, PhD, is an Associate Professor in the Gangarosa Department of Environmental Health at Emory University, where he leads the Comprehensive Laboratory for Untargeted Exposome Science (CLUES). He also serves as adjunct Assistant Professor at Utrecht University and co-leads the NEXUS Emory University Collaborative Hub. Before joining Emory, he was an Assistant Professor at the Icahn School of Medicine at Mount Sinai in New York and a member of their Institute for Exposomics Research.
Dr. Walker is an environmental engineer and analytical chemist whose research has focused on operationalizing new analytical strategies for measuring the exposome. The exposome represents a paradigm shift in how we understand environmental contributions to human health; however, realizing this vision requires analytical methods capable of capturing the chemical complexity of human exposures. Walker’s laboratory has addressed this challenge by developing high-throughput, untargeted high-resolution mass spectrometry approaches that can simultaneously measure over 50,000 chemical signals in biological samples, including exposure biomarkers, nutrients, dietary chemicals, endogenous metabolites, and markers of biological response. These methods enable discovery-based research through exposome-wide association studies (ExWAS), which are better suited to capture complex, real-world exposures to reveal novel exposure-disease relationships and provide new insights into the mechanisms underlying diseases in humans.
The exposome methods developed in Dr. Walker’s laboratory have been applied across multiple research areas, including cancer, metabolic disease, neurodevelopmental conditions, and reproductive health, while also advancing methods for measuring biomarkers of complex exposures of emerging concern, such as microplastics and e-waste. Current projects focus on building disease-exposome atlases that map the relationships between chemical exposures and health outcomes at population scale, providing resources that can guide future research and intervention strategies. By demonstrating that comprehensive exposome measurements are achievable in a high-throughput and cost-effective manner, Dr. Walker’s research has helped establish a foundation for integrating exposomics into precision medicine and environmental health. His work bridges the gap between analytical chemistry innovation and translational applications, enabling researchers across disciplines to incorporate exposome data into their studies.
Dr. Walker received his PhD in Environmental and Water Resources Engineering from Tufts University, during which time he received extensive training in metabolomics, exposomics, and toxicology in the Clinical Biomarkers Laboratory at Emory University. He has published over 150 peer-reviewed manuscripts and has maintained continuous funding for exposome methods development and application since 2018. He is a member of the Emory HERCULES Exposome Center, an NIH-funded Environmental Health Sciences Center that provides key infrastructure and expertise for developing and refining new exposome tools and technologies. Through CLUES, his laboratory continues to provide high-quality untargeted screening of biological samples for nutrition, precision medicine, and environmental health research, supporting both internal and collaborative projects that advance the exposome field.
Fun Fact: Dr. Gary Miller (NEXUS MPI) provided Dr. Walker’s first introduction to the exposome ~14 years ago when the former helped the latter receive funding to visit Dr. Dean Jones’s (NEXUS Co-I) laboratory as a PhD student to study the exposome and neurodegenerative diseases.