Photo of Mary Ellen Tucillo

Mary Ellen Tuccillo

Senior Environmental Scientist

Staring out of an airplane window not long after my first geology course, I was amazed at how the landscape features jumped out at me. I saw clearly how river flow, sediment, and time had interacted. That wonder is still with me as I apply what I know about geology and geochemistry to protect our nation’s groundwater, drinking water, and infrastructure. My work is diverse, and I like it that way because it allows me to bring a deep understanding of the earth and environmental sciences to a wide array of subsurface and surface environmental problems.


Dr. Mary Ellen Tuccillo (she/her/hers) is a senior environmental scientist with more than 20 years of experience in basic and applied research and regulatory development. With a strong background in geochemistry, she supports water quality work on topics including subsurface biogeochemical processes, soil and groundwater contamination, aquifer recharge, underground injection, hydraulic fracturing, geologic carbon sequestration, source water protection, water reuse, nanomaterials, and the impacts of wet weather flows on drinking water sources.

Mary Ellen has provided technical leadership on dozens of projects for the U.S. Environmental Protection Agency, Water Research Foundation, and others. She has extensive experience in sediment and groundwater sampling and analysis and bench-scale experimental work. She has researched microbially mediated redox processes in groundwater, the speciation of heavy metals in suburban runoff, and stormwater management. She has presented her work widely at government workshops and national conferences. Mary Ellen has conducted analyses of hydraulic fracturing fluid data, and she served as a the lead author on the wastewater chapter of EPA's Assessment of the Potential Impacts of Hydraulic Fracturing for Oil and Gas on Drinking Water Resources. She has also served as a research fellow with EPA's Urban Watershed Management Branch.

Mary Ellen holds a B.S. in geology from Yale University, an M.S. in geology from the University of Michigan, and a Ph.D. in environmental sciences from the University of Virginia. When not working, she enjoys hiking, photography, and playing the violin.