Drinking water source and exposure to regulated water contaminants in the California Teachers Study cohort

Distributions of long-term (1990–2015) average concentrations of community water system (CWS) exposures, and percent of years the annual average concentration was at or above the maximum contaminant level (MCL) and half of the MCL.

Author: Spaur, Maya; Medgyesi, Danielle N.; Bangia, Komal; Madrigal, Jessica M.; Hurwitz, Lauren M.; Beane Freeman, Laura E.; Fisher, Jared A.; Spielfogel, Emma S.; Lacey, James V.; Sanchez, Tiffany; Jones, Rena R.; Ward, Mary H.

Description: BACKGROUND: Pollutants including metals/metalloids, nitrate, disinfection byproducts, and volatile organic compounds contaminate federally regulated community water systems (CWS) and unregulated domestic wells across the United States. Exposures and associated health effects, particularly at levels below regulatory limits, are understudied.

OBJECTIVE: We described drinking water sources and exposures for the California Teachers Study (CTS), a prospective cohort of female California teachers and administrators.

METHODS: Participants’ geocoded addresses at enrollment (1995-1996) were linked to CWS service area boundaries and monitoring data (N=115,206, 92%); we computed average (1990-2015) concentrations of arsenic, uranium, nitrate, gross alpha (GA), five haloacetic acids (HAA5), total trihalomethanes (TTHM), trichloroethylene (TCE), and tetrachloroethylene (PCE). We used generalized linear regression to estimate geometric mean ratios of CWS exposures across demographic subgroups and neighborhood characteristics. Self-reported drinking water source and consumption at follow-up (2017-2019) were also described.

RESULTS: Medians (interquartile ranges) of average concentrations of all contaminants were below regulatory limits: arsenic: 1.03 (0.54,1.71) µg/L, uranium: 3.48 (1.01,6.18) µg/L, GA: 2.21 (1.32,3.67) pCi/L, nitrate: 0.54 (0.20,1.97) mg/L, HAA5: 8.67 (2.98,14.70) µg/L, and TTHM: 12.86 (4.58,21.95) µg/L. Among those who lived within a CWS boundary and self-reported drinking water information (2017-2019), approximately 74% self-reported their water source as municipal, 15% bottled, 2% private well, 4% other, and 5% did not know/missing. Spatially linked water source was largely consistent with self-reported source at follow-up (2017-2019). Relative to non-Hispanic white participants, average arsenic, uranium, GA, and nitrate concentrations were higher for Black, Hispanic and Native American participants. Relative to participants living in census block groups in the lowest socioeconomic status (SES) quartile, participants in higher SES quartiles had lower arsenic/uranium/GA/nitrate, and higher HAA5/TTHM. Non-metropolitan participants had higher arsenic/uranium/nitrate, and metropolitan participants had higher HAA5/TTHM.

IMPACT: Though average water contaminant levels were mostly below regulatory limits in this large cohort of California women, we observed heterogeneity in exposures across sociodemographic subgroups and neighborhood characteristics. These data will be used to support future assessments of drinking water exposures and disease risk.

Subject headings: Humans; Female; California; Drinking Water; Water Pollutants, Chemical; Prospective Studies; Middle Aged; Environmental Exposure; Adult; Water Supply; School Teachers; Uranium; Arsenic; Environmental Monitoring; Nitrates; Disinfection by-products; Environmental justice; Exposure modeling; Metals; Volatile organic compounds

Publication year: 2025

Journal or book title: Journal of Exposure Science & Environmental Epidemiology

Volume: 35

Issue: 3

Pages: 454-465

Find the full text: https://www.strategian.com/fulltext/Spaur2025.pdf

Find more like this one (cited by): https://scholar.google.com/scholar?cites=13641266961759627538&as_sdt=1000005&sciodt=0,16&hl=en

Serial number: 4171

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