Natasha Sihota is an Environmental Hydrogeologist with the Site Assessment and Remediation team of Chevron's Energy Technology Company in San Ramon, California. She provides technical guidance for domestic and international hydrocarbon remediation projects and supports internal technology research and development for site assessment and remediation tools. Natasha developed the surficial CO2 efflux approach for evaluating NAPL management through natural source zone depletion (NSZD). She has extensive experience with applying the NSZD concept to achieve different site management objectives. Natasha has been involved in developing guidance documents in the US for evaluating and applying the NSZD concept through the American Petroleum Association, ITRC, and other state groups. She has provided NSZD training to environmental regulators, industry colleagues, and university groups. Natasha earned a bachelor's degree in hydrogeology, ecology and environmental chemistry from the University of British Columbia, Canada in 2009 and a Ph.D. in contaminant hydrogeology in 2014.