Project Description (Abstract) Per- and polyfluoroalkyl substances (PFAS) are contaminants of emerging concern which pose a direct threat to ecological and human health. Since 2019, the EPA Chemical Pollutants Assessment Division (CPAD) has been conducting systematic literature reviews of specific PFAS. The goal of these reviews is to compile the numerous sources of toxicological data describing these compounds and make the data more widely available to other government agencies, researchers, stakeholders, and the American public. The EPA is currently working towards the ambitious goal of reviewing and reporting on over 9,000 PFAS by 2022. The EPA CPAD aims to achieve this goal using "Systematic Evidence Mapping" (SEM) techniques. The proposed K.C. Donnelly externship project would involve the applicant's participation in the screening, data extraction, and data visualization processes required to construct the evidence maps posted on the EPA PFAS dashboard. Outcomes of the externship project for the applicant would include an enhanced familiarity with PFAS' wide-ranging physical-chemical properties and associated toxicological effects; intimate knowledge of the EPA CPAD's SEM process, data management strategies, and data visualization techniques; as well as a greater insight into the role of Federal government in protecting our natural environment.