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Seasonal occurrence and distribution of per- and polyfluoroalkyl substances in an urbanized tropical estuarine embayment: San Juan Bay, Puerto Rico
Citation:
Katz, D., J. Sullivan, I. Capielo-Cosme, E. Huertas, Alana Hanson, M. Molina, T. Boving, AND A. Oczkowski. Seasonal occurrence and distribution of per- and polyfluoroalkyl substances in an urbanized tropical estuarine embayment: San Juan Bay, Puerto Rico. SETAC North America, 43rd Annual Meeting, Pittsburgh, PA, November 13 - 17, 2022.
Impact/Purpose:
Per- and polyfluorinated alkyl substances (PFAS) are a class of chemicals with thousands of variations that may pose ecological risk. In this study, we quantified a small list of PFAS compounds and used a chemical reaction to reveal other PFAS present that were not on the targeted list. Samples were collected during both the dry and rainy seasons in surface waters of San Juan Bay, Puerto Rico to better assess the risk these compounds may pose to human and ecological health in a tropical estuary. PFAS were present throughout the estuary; the lowest PFAS values occurred at points with the shortest tidal flushing time and the highest values occurred in the tidally restricted lagoons. Clear differences in PFAS concentrations were observed between seasons and between different parts of the estuary. At many stations, PFAS concentrations during the rainy season were more than double those at the same stations in during dry seasons. After the chemical reaction, higher PFAS concentrations were observed in almost all samples – often a factor of 5 – 10 times higher compared to unaltered samples. The large differences in PFAS levels between methods underscores the need to routinely perform a more comprehensive PFAS analysis. The San Juan Bay estuary system is heavily relied upon by the local population for recreation and livelihood, and chemical contamination potentially exposes an underserved community in the tidally connected Cano Martin Peña to adverse risk.
Description:
Per- and polyfluorinated alkyl substances (PFAS) are a large class of organic contaminants associated with both point and non-point source contamination. Most environmental reports of PFAS are from temperate locations and estimates of PFAS exposure in the tropical environment are limited, where climatic and socio-economic differences from temperate locations may pose an increased ecological risk. In this study, we quantified a targeted list of PFAS compounds and total PFAS using the total oxidizable precursors (TOP) method during the dry and rainy seasons in surface waters of San Juan Bay, Puerto Rico to better assess the risk these compounds may pose to human and ecological health in a tropical estuary. PFAS were present throughout the estuary, with the lowest values occurring at points with the shortest hydraulic residence time and highest values typically occurring nearest to the tidally restricted lagoons. Clear differences in PFAS concentrations were observed between seasons and between sub-embayments of the estuarine system, with targeted ∑PFAS concentrations ranging from 0.9 – 25.9 ng/L during the dry season and 1.9 – 32.9 ng/L during the rainy season. However, at many stations ∑PFAS concentrations in November 2019 (rainy) were more than double those at the same stations in March 2021 (dry). After the TOP method, higher PFAS concentrations were observed in almost all samples – often a factor of 5 – 10 times higher compared to un-oxidized samples. These large increases post-TOP method underscore the need for comprehensive PFAS analysis, where high concentrations of the dark pool of novel PFAS without authentic standards would otherwise remain unknown. The San Juan Bay estuary system is heavily relied upon by the local population for recreation and livelihood, and chemical contamination potentially exposes an underserved community in the tidally connected Cano Martin Peña to adverse risk.
