Abstract
Abstract
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.
Publisher
Springer Science and Business Media LLC
Reference72 articles.
1. Levin R, Villanueva CM, Beene D, Cradock AL, Donat-Vargas C, Lewis J, et al. US drinking water quality: exposure risk profiles for seven legacy and emerging contaminants. J Expo Sci Environ Epidemiol. 2024;34:3–22.
2. United States Environmental Protection Agency. Information about public water systems. In: Drinking water requirements for states and public water systems. 2022. Available from: https://www.epa.gov/dwreginfo/information-about-public-water-systems
3. California Waterboards. Testing your private domestic well. 2020. Available from: https://www.waterboards.ca.gov/publications_forms/publications/factsheets/docs/dom_well_factsheet.pdf
4. United States Environmental Protection Agency. National Primary Drinking Water Regulations. 2024. Available from: https://www.epa.gov/ground-water-and-drinking-water/national-primary-drinking-water-regulations#one
5. Nolan BT, Ruddy BC. Nitrate in the ground waters of the United States—assessing the risk: National Water-Quality Assessment (NAWQA) Program. U.S. Geological Survey Fact Sheet 092-96. 1996. Available from: https://pubs.usgs.gov/fs/1996/fs-092-96/