Greg Lehn joined Life Cycle Geo, LLC in February 2024. His expertise lies in aqueous geochemistry, mineral weathering, reactive transport modeling, stable and radiogenic isotopes, and forensic geochemistry. Greg’s client portfolio spans a diverse range of sectors, including mining, power, industrial, solid waste, oil and gas, and water treatment. Greg enjoys incorporating complex environmental datasets into “fit-for-purpose” hydrogeochemical conceptual models that help unravel the most challenging questions posed by clients. His project experience includes material characterization, water quality modeling using software including PHREEQC, The Geochemist’s Workbench, and MIN3P, as well as forensic geochemical investigations and contaminant source identification. During his Ph.D. research at Northwestern University, Greg conducted a multi-proxy investigation (major ions, trace metals, stable and radiogenic isotopes) focused on understanding the impact of seasonal permafrost thaw dynamics on mineral weathering in watersheds located on the North Slope of Alaska. Greg currently resides in Denver, Colorado. When he isn’t working, Greg enjoys spending time with his wife and two sons, running, traveling, backpacking, skiing, and baking.