Principal Technical Expert Environmental Soil & Groundwater
Shell Global Solutions US Inc.
George DeVaull is employed by Shell Global Solutions US Inc. in Houston, Texas. His work includes evaluation of chemical fate and transport in the environment, development and application of risk assessment methods, and guidance and standards development. He has worked on many hundreds of soil and groundwater projects across the oil and gas industry.
Natural Source Zone Depletion Estimated based on Compositional Change
Spills and releases of petroleum can result in zones of non-aqueous phase liquids (NAPL) in soils and groundwater. The chemical constituents in the NAPL deplete at different rates due to dissolution, volatilization, and degradation, and the NAPL composition will vary over time. Here we present estimates for several case examples, including bulk NAPL and constituent depletion trends over time. Methods for selecting the most conserved markers in the NAPL mixtures, estimating depletion based on those markers, and confidence in the depletion estimates are shown.