Tapwater Analysis Project (TAP): Testing Chemicals in Water
Creators: name: University Of California Office Of The President
Publisher: name: University of California Office of the President
publisherIdentifier: https://ror.org/00dmfq477
publisherIdentifierScheme: ROR
Year: 2024

description: Virtually nothing is known about chemical contaminants in drinking water and how they influence breast cancer risk. While 32 chemicals commonly found in U.S. drinking water supplies have been shown to cause mammary tumors in animals, this likely represents the tip of the iceberg as only a fraction of potential cancer-causing contaminants are monitored in drinking water. California drinking water is threatened with chemical contamination from multiple sources, including current and historic industrial sites, mining, pesticide use, and sewage discharge. As a first step towards understanding the potential risks of breast cancer from drinking water contaminants, there is a clear need to screen drinking water for unmonitored and unregulated chemicals that are known or suspected carcinogens, mammary gland toxicants, or endocrine disruptors. Furthermore, with over 80,000 chemicals used in U.S. commerce today, most of which have not been evaluated for breast cancer risk, it is important to also identify the presence of unknown contaminants that could function as breast carcinogens based on similar chemical properties. Recent advances in the development of laboratory techniques for ‘non-targeted analyses’ has now made it possible to test for the presence of tens of thousands of potential chemicals in water. 
 Research question(s) or central hypotheses: This proposal is designed to identify drinking water contaminants that may play a causal role in breast cancer by conducting targeted and non-targeted testing for contaminants in a cross section of California communities where water may be impacted by contaminants that are not monitored under current regulations. Our central hypotheses are: 1.) Contaminants that are currently unregulated and untested occur in California drinking water; 2.) Some unregulated and untested contaminants are potential contributors to breast cancer; and 3.) Contaminant patterns in water differ in agricultural, urban, and former mining areas. 
 General methodology: Building on recently-collected survey information on drinking water sources and consumption patterns in the California Teachers Study (CTS), we will collect a minimum of 60 household tap water samples from CTS members living in the Central Valley, Gold Country, Los Angeles Region, and the San Francisco Bay Area. Within these broad geographic regions, we will target our sampling to include representation from areas with suspected water quality challenges, areas with elevated breast cancer rates, and areas that are socioeconomically disadvantaged. Samples will be analyzed for a large suite of targeted chemicals that have been identified to be of concern for breast cancer, including perfluorinated industrial chemicals, metals, pesticides, pharmaceuticals, and hormones, as well as for unknown contaminants. The water samples will also be assessed for evidence of hormonal activity in cell cultures. Individual water testing results will be provided to participants and we will work with community-based organizations on the interpretation of study findings and results dissemination. 
 Innovative elements: The mapping expertise offered by members of our study team from the California Environmental Health Tracking Program (“Tracking California”) provides us the unique opportunity to develop a water sampling strategy that targets specific regions in the State, simultaneously considering areas with elevated breast cancer rates, with vulnerability to ground water contamination, and with substantial populations that are underserved or disadvantaged. Furthermore, this project innovatively weaves together state-of-the-art laboratory techniques conducted by top Federal agencies to measure both targeted and non-targeted chemicals with novel methods for assessing the overall endocrine disrupting capacity of the mixtures of chemicals present in the water samples collected. This will help fill critical gaps in our knowledge of what chemicals California women may be exposed to through their drinking water and to better understand the degree to which they may be relevant to breast cancer risk due to endocrine-disrupting capabilities. 
 Advocacy involvement and relevance to the human issues associated with breast cancer: We are principally partnering with two community groups, Clean Water Action/Fund and Sierra Streams Institute. These groups will be working with us through all phases of the project, and will be conducting the sample collection. We will have broader input from a subgroup of the current Tracking California Implementation Advisory Group that includes breast cancer, environmental justice, and other organizations. All of our community partners will be actively engaged in translating the results of the study into actionable policy recommendations that could ultimately reduce the burden of breast cancer by mitigating exposures to cancer causing contaminants in drinking water.