William Goodfellow is a Principal Scientist and the Director of Exponent’s Ecological and Biological Sciences practice. He is a Board-Certified Environmental Scientist (BCES) with special emphasis in Environmental Toxicology and a Fellow of the Society of Environmental Toxicology and Chemistry (SETAC). Mr. Goodfellow has more than 35 years of experience in wastewater treatment, environmental toxicology and causal effect assessments including addressing impacts from physical and chemical stressors such as metals, dioxin/furans, PCBs, PFAS, PAHs, 6PPD-Q, microplastics, pesticides/herbicides, pharmaceuticals, and personal care products. Mr. Goodfellow is an internationally recognized expert in environmental assessment, toxicology, Toxicology Reduction Evaluation (TRE) technology and wastewater permitting. Mr. Goodfellow has served on peer-review panels, advisory boards, task forces, and editorial committees for natural resources, environmental assessment, toxicology, and TRE issues, as well as being widely published.