Exposure assessment of per- and polyfluoroalkyl substances (PFAS) and disinfection by-products (DBPs) in drinking water during pregnancy

Abstract

BACKGROUND AND AIM: Prenatal exposure to per- and polyfluoroalkyl substances (PFAS) and disinfection by-products (DBPs) have been linked to multiple adverse birth outcomes in epidemiological studies. The aim of this study was to comprehensively assess exposure to these chemicals in drinking water during pregnancy in the Barcelona Life Study Cohort (BiSC). METHODS: A total of 1086 pregnant women living in the Barcelona Metropolitan area were recruited at the first trimester of pregnancy and followed by surveys until delivery (2018-2021). Water ingestion habits were ascertained at the first and third trimesters through questionnaires. Tap water samples were collected in a subset (N=105) during the 3rd trimester to analyze 35 PFAS. Routinely monitored DBPs (trihalomethanes, THMs) were obtained from the local public health authority for the pregnancy period (N=183). PFAS and DBPs concentrations were modelled based on geolocation and temporal variation to predict concentrations in the residential water supply of each participant from conception until delivery. RESULTS: 5/35 PFAS were detected, namely perfluoropentanoic acid (PFPeA), perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorobutane sulfonic acid, (PFBS), and perfluorooctane sulfonic acid (PFOS), at median (Interquartile range; IQR) concentrations (ng/L), respectively, of 5.7(4.3-8.3), 12.0(10.5-12.0), 3.4(2.5-4.7), 8.3(7.2-10.5), and 13.0(11.8-14.0). Median (IQR) concentrations (μg/L) of THMs were 18.6(7.3-27.6) for chloroform, 9.4(5.6-12.4) for dibromochloromethane, 6.4(2.9-10.3) for bromodichloromethane, and 26.1(16.2-36.0) for bromoform. Drinking water consumed at home was bottled (64.8%), filtered (22.9%), and tap water (12.3%). Water used for cooking was from tap (78.4%), filtered (15.7%), and bottled water (0.6%). Individual exposure estimates by trimester and for the whole pregnancy will be calculated using residential levels multiplied by amount and type of water consumed. CONCLUSIONS: The study population is exposed to relatively low concentrations of PFAS in drinking water, and THMs have a significant component of brominated species. KEYWORDS: drinking water; PFAS; disinfection byproducts; exposure assessment.