He joined the Towson University Chemistry Department in 2007 as an Assistant Professor and was promoted in 2012. In 2014, he was appointed the Graduate Program Director for the Environmental Science. At Towson, He has taught General Chemistry and Introduction to Environmental Chemistry for undergraduates and Environmental Chemistry and Ecotoxicology for the Environmental Science Graduate Program. Prior to Towson he spent three years at Stephen F. Austin State University in Nacogdoches, TX. While at SFA, David was an Assistant Professor of Environmental Science, managed the Environmental Assessment Laboratory, and taught a broad range of classes including Introduction to Environmental Science, Environmental Measurements, Environmental Assessment, Ecotoxicology, and Coastal and Estuarine Environmental Issues.