Identification of Potential Sources of PFAS in the Gurabo Water Treatment Plant Watershed

Abstract

The drinking water treatment plant (WTP) of the municipality of Gurabo in Puerto Rico, is owned and operated by the Puerto Rico Aqueduct and Sewer Authority (PRASA). In its 2023 drinking water quality report, the WTP detected the presence of per- and polyfluoroalkyl substances (PFAS). Although there are thousands of PFAS compounds, the report specifically identified four: PFBA, PFHxA, PFOS, and PFPeA. This study aims to identify potential sources of PFAS contamination in the surface waters supplying the Gurabo WTP's watershed. Additionally, the research explores the relationship between PFAS concentrations and land use types within the watershed, comparing estimated PFAS levels from different land uses to the actual concentrations reported in 2023. The study identified 22 industry types within the watershed with potential PFAS contamination due to their use of these chemicals in their processes. The comparison between estimated and reported PFAS concentrations revealed an error margin of 10%, providing insights into the accuracy of land use association with contaminant concentrations under study. Key Terms - Gurabo Water Treatment Plant, Land Cover/Use, NAICS Codes, PFAS, PRASA, Watershed.