Breast Cancer Risks from California's Gold Mining Legacy
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: 2025

description: Introduction: Arsenic (As) and cadmium (Cd), cancer-causing metals possibly associated with increased risk of breast cancer, are widespread contaminants throughout the Gold Country region of northern CA as a result of extensive historic gold mining. This region is also characterized by breast cancer incidence rates significantly higher than the State average. Findings from two Community Health Impacts of Mining Exposure (CHIME) pilot studies found elevated As body burdens in local women compared to what might be expected from national data, higher levels of Cd in long-term residents, and higher body burden and residential soil levels of some metals in women with a history of breast cancer. Data from both studies suggested that body burden levels of As were higher in women who reported routine consumption of produce from home gardens and were active in running and walking on local trails. In a third pilot study we are currently working alongside the community to conduct an extensive and comprehensive exposure assessment to identify potential routes of exposure by identifying environmental hazards in a sample of participants’ home, garden, school and recreational areas. The goal of the proposed study is to further pursue the implications of these pilot studies’ findings by taking an expanded look at the pattern of breast cancer incidence throughout the Gold Country region and to collect information on personal and household risk factors that might help explain pilot study findings to date. Question(s) or hypotheses: The primary hypotheses of this proposal are 1) Breast cancer incidence is higher in closer proximately to mines sites; 2) Cd and As body burden is associated with environmental exposures through gardening and trail use in areas with mining residue. General methodology: The proposed study is an effort to continue active community engagement in an investigation into the health consequences of living in a mining-impacted community. An established and expanded Community Advisory Board (CAB) will guide and oversee all phases of the study. The aims of this study are to assess patterns of breast cancer incidence in Gold Country using geographic information about mines and other land features, as well as socioeconomic factors. We will also conduct an exposure assessment by recruiting and training citizen scientists to estimate residents’ daily exposure to cadmium and arsenic. This project will continue the environmental risk communication and dialogue in the community, disseminate and explain study results, and ultimately generate community guided strategies for exposure reduction. Innovative elements: The study will retain three innovative elements of the CHIME pilot studies: 1) CHIME was the first ever CBCRP-funded CRC project to be awarded to a community partner as prime with the academic partner as the sub-contractor, reflecting the project’s genesis within the community; 2) CHIME also broke new ground as the first ever project approved by the scientific partner’s IRB to return individual results to participants, identified by the CAB as critical to the community’s right to know; and 3) CHIME featured citizen science, with a continued view to active participant engagement to conduct further data collection to increase participation in historically underrepresented groups . In addition, new work with our University of Arizona partner, is developing innovative methods of assessing sources of exposure to the metals of interest to inform potential for remediation and risk reduction. Community involvement: This is a project conceived by the community, prompted by concern among local residents about the health effects of their mining legacy in light of efforts to reopen mining operations. In addition, environmental assessments by SSI have revealed widespread heavy metal contamination. The primary aim of CHIME is to establish a community dialogue and involve the community in all aspects of the study. A key element of community engagement is to train participants as citizen scientists to collect environmental data, an approach that is central to SSI’s stewardship model. With 19 years of citizen-generated validated environmental data, SSI will lead the environmental data collection effort by using rigorous protocols and training participants in their use. Future Plans: Future research is expected to include epidemiological research on other outcomes related to Cd and As such as child development, birth outcomes, and other cancers. Future studies would also benefit the community by disseminating strategies that minimize exposures and prevent the target metals from entering homes, thereby reducing body burden. The findings of the pilot and of future studies will also be used to support requests for funding of efforts that engage the local community in cleaning up mining’s toxic legacy throughout Gold Country.