Cadmium and arsenic exposure in a mining impacted community

Institution: Sierra Streams Institute
Investigator(s): Peggy Reynolds, Ph.D. - Joanne Hild, M.S. Zoology -
Award Cycle: 2013 (Cycle 19) Grant #: 19AB-2400 Award: $202,989
Award Type: CRC Pilot Award
Research Priorities
Etiology and Prevention>Etiology: the role of environment and lifestyle



Initial Award Abstract (2013)

Introduction: Arsenic (As) and cadmium (Cd), both carcinogenic metals, are pervasive contaminants throughout the Gold Country region of northern California as a result of extensive gold mining that began with the California Gold Rush of 1849. Exposure to Cd has been associated with increased risks of breast and endometrial cancers while inorganic As at low concentrations causes increased growth of estrogen-responsive breast cells. No human health studies have been conducted in this region to determine whether residents have an elevated level of these contaminants in their bodies, despite the fact that the three most populous counties in Gold Country have breast cancer rates that rank in the top ten of the 58 counties in California. This project seeks to determine whether further study is warranted of a link between breast cancer incidence and exposure to legacy mining contaminants.

Question(s) or hypotheses: The primary hypothesis of this proposal is that build-up of legacy mining contaminants, namely Cd and As, is elevated in the bodies of residents in a gold mining community.

General methodology: The proposed study is an effort to engage the community in an investigation into the human health consequences of residence in a mining-impacted community. Community engagement will be accomplished by means of two community forums, to be hosted by Sierra Streams Institute (SSI), and the establishment of a Community Advisory Board. Community input will direct all phases of the proposed human health study. A total of 60 women over the age of 21 who are residents of western Nevada County will be recruited for a biological study. The participants will complete a questionnaire to elicit basic sociodemographic, residential, and activity data. The participants will provide minimally invasive biological samples consisting of first-morning urine for the measurement of As and Cd, and toenail clippings for the measurement of As. Statistical analyses of the measured concentrations of these metals and of questionnaire data will be conducted to determine the relative contributions of length of residence in Gold Country, residential proximity to mine waste, activity patterns, and sociodemographic characteristics.

Innovative elements: The proposed study would be the first human health study conducted in the Gold Country region focused specifically on body burden of mining-related toxins, and on the relationship between body burden and factors related to residence in Gold Country.

Community involvement: The project was conceived at the community level, prompted by widespread opposition to plans to reopen major gold mining operations. SSI is a non-profit scientific monitoring, restoration, education and research organization based in Nevada City. Founded as Friends of Deer Creek in 1996 by a group of concerned local residents to protect the creek, the group remains a citizen-based grassroots organization dedicated to engaging local people in the stewardship of their own environment. A 2011 community conference hosted by SSI and CBCRP, to encourage community-based projects that advance knowledge of breast cancer etiology, led to demand for a study of the health effects of living among abandoned mine waste. A community survey conducted by SSI volunteers in 2012 confirmed the level of concern, with 85% of respondents agreeing or strongly agreeing that abandoned gold mine waste is a human health hazard. SSI on behalf of the community has worked closely with CPIC and UNR over the course of fourteen months to develop a project that will address the community’s concern. The primary aim of the project is to involve the community in all stages of the study, from participating in a community advisory board, designing the study, participating in the study, interpreting the findings, and guiding future plans.

Future Plans: The primary goal of the proposed pilot study is to determine whether the findings justify further epidemiological studies. Further research activities may include: evaluating the geographic distribution of breast cancer incidence in relation to the location of abandoned mine sites; biomonitoring of additional mining contaminants such as lead and mercury; expanding biological specimen collection to include a larger geographic area; residential dust sampling; studies of other outcomes related to exposure to mining contaminants such as other cancers, birth outcomes, and overall mortality. This planned future research will benefit residents of the targeted communities by validating and empowering the work of citizen scientists, determining and disseminating strategies that will minimize exposure, engaging the community in cleanup efforts and information campaigns, and supporting requests for funding to clean up mining’s toxic legacy throughout Gold Country.




Final Report (2016)

Cadmium and Arsenic, cancer-causing metals associated with increased risk of breast and uterine cancers, are widespread contaminants throughout the Gold Country of northern CA as a result of extensive historic gold mining. Although both metals are known to be endocrine-disruptors and carcinogens, no human health studies have been conducted to determine whether levels of these contaminants are elevated in residents of Gold Country, despite the fact that age-adjusted breast cancer rates rank in the top ten of the 58 counties in California. The study was designed to engage the local community in investigating whether further study is warranted to determine whether body burden of cadmium and arsenic is related to length of residence in Gold Country, residential proximity to mine waste, activity patterns and/or sociodemographic characteristics.

The community-academic team successfully completed all phases of the project. Sixty women were recruited as participants, all successfully returned questionnaires and biological samples, and data were entered into a database. The assay results from the California Environmental Health Laboratory consisted of a panel of ten metals including the targeted metals, cadmium and arsenic. Individual results were returned to all participants who requested them, and were discussed in a dedicated participant meeting. Summary results of the study were presented and discussed at a subsequent community meeting and through radio and newspaper interviews.

Major accomplishments include the development of a successful community-academic partnership, establishment of a community-wide dialog about the human health consequences of living in a mining-impacted environment and possible remediation to prevent exposure, discovering significantly elevated body burden of cadmium among older women who are long term residents of Gold Country compared to younger and recent arrivals to the area and discovering elevated body burden levels of arsenic in our study participants compared to national samples.

Findings from this pilot study gave rise to a second pilot to address two additional issues: (1) the association between body burden of arsenic and cadmium and breast cancer status, (2) the association between body burden of these chemicals and levels in household dust, water and soil samples. The second pilot study began in 2015 and is currently in progress.




Conference Abstract (2016)

Cadmium and Arsenic Exposure in a Mining-Impacted Community: A Community Based Participatory Research Project

Joanne Hild, Executive Director, Sierra Streams Institute
Jane Sellen, Watershed Coordinator, Sierra Streams Institute
Peggy Reynolds, Senior Research Scientist, Cancer Prevention Institute of California;
Katy Janes, Watershed Coordinator, Sierra Streams Institute
Christine Duffy, Senior Program Manager, Cancer Prevention Institute of California
Julie Von Behren, Research Associate, Cancer Prevention Institute of California
Ruiling Liu, Research Associate, Cancer Prevention Institute of California

Arsenic (As) and cadmium (Cd), both carcinogenic metals, are pervasive contaminants throughout the Gold Country region of northern California as a result of extensive gold mining that began with the California Gold Rush of 1849. Exposure to Cd has been associated with increased risks of breast and endometrial cancers while inorganic As at low concentrations causes increased growth of estrogen-responsive breast cells. No human health studies had been conducted in this region to determine whether residents have an elevated level of these contaminants in their bodies, despite the fact that the three most populous counties in Gold Country have breast cancer rates that rank in the top ten of the 58 counties in California.

In response to community concerns about elevated breast cancer incidence in the region and the endocrine-disrupting properties of the target metals of interest a study was initiated (“Community Health Impacts from Mining Exposures,” CHIME) in collaboration between a community environmental organization, Sierra Streams Institute and a cancer research organization, the Cancer Prevention Institute of California with two specific aims:

Aim 1: Establish a community dialogue about exposure to historical mining contaminants, the purpose and design of a health and exposure study, how best to give back individual study results, and ways to limit exposure, all through community forums and a community advisory board (CAB).

Aim 2. Conduct a pilot biological measurement study to characterize body burden of Cd and As in relation to sociodemographic characteristics, length of residency, residential proximity to mines and mine waste, and the types of daily and recreational activities performed in the Gold Country.

Community input through a CAB directed all phases of the study. A total of 60 women over the age of 21 who were residents of western Nevada County were recruited. Participants completed a questionnaire and provided biological samples consisting of first-morning urine for the measurement of As and Cd. Statistical analyses of the concentrations of these metals and of questionnaire data were conducted to determine the relative contributions of length of residence in Gold Country, activity patterns, and sociodemographic characteristics. Levels for the two metals were compared to those for similarly aged women from the most recent National Health and Nutrition Survey as representative of national averages.

Notable findings from the study were: 1) although on average, cadmium levels in CHIME participants were lower than the national average, they were significantly elevated in women over age 35 who had lived in Gold Country 10 years or more; 2) average levels of arsenic were significantly higher than the national average.

Individual results were returned to participants. Although not a common practice when health effects are not fully understood, the CAB and many community members felt strongly that it was an individual’s right to know about her own body levels.

It is hoped that the current research as well as future activities arising from this community-academic partnership will benefit residents of the Gold Country region of California as well as other communities impacted by mining activity.