Sierra Streams Institute is engaged in research in all aspects of watershed science, in an effort to expand our understanding of how to protect and improve watershed health and to protect the health of the people who live in specific watersheds. We undertake studies, publish papers, present at conferences, and share data with universities and agencies.

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Community Health Impacts of Mining Exposure

Age-Adjusted Invasive Cancer Incidence Rates by County in California, 1988 – 2014. Based on Oct 2016 Extract. California Cancer Registry. Retrieved Jan 12, 2018, from

Our Rural Health Research and Advocacy Initiative is to provide environmental health research and advocacy for rural communities of California’s Gold Country. An integral sector of this research is the Community Health Impacts of Mining Exposure (CHIME) study, funded by state tobacco taxes through the California Breast Cancer Research Program, investigated the concentrations of heavy metals, like cadmium and arsenic, in a group of approximately 100 Nevada County women. We not only found interesting links between body burden (the total amount of a particular chemical present in a human’s body) and the amount of time living in the area, but were also able to educate the community about the health hazards of heavy metal exposure. The second phase of the study focused on the amount of cadmium and arsenic in the bodies of women with and without breast cancer residing in historical Gold Country.

These two metals are of interest because they are found at high levels throughout Gold Country, are known carcinogens and may play a role in developing breast cancer.  The three most populous counties in Gold Country, including Nevada County, have breast cancer rates that rank in the top ten counties in California. We are continuing our research in this field by expanding the research to include all counties within Gold Country, we are also conducting another pilot study expanding this investigation by assessing whether young children, who represent a particularly important window of vulnerability for breast cancer, are being exposed to the metals of concern in preschool gardens, through incidental soil ingestion, inhalation of metal-containing dust, and consumption of plants grown in local gardens.


One viable strategy for abandoned mine sites in riparian areas such as Providence Mine is phytoremediation. Phytoremediation uses green plants to alleviate environmental contamination at a fraction of the cost compared to traditional methods. Additionally, this remediation technique has two-fold benefits of both contamination removal and ecological restoration.

Sierra Streams Institute has been researching phytoextraction, a specific type of phytoremediation, using Providence Mine as our laboratory. In phytoextraction, the plant concentrates the contaminant into its aboveground biomass, that biomass can then be harvested and used for something else like biofuels or energy via incineration, with the contaminants remaining in ash that can then be disposed of as hazardous waste. Biomass produced from phytoextraction could also be used as a raw material for paper production and charcoal, or a source for textiles. Research findings were published in Ecological Restoration and presented at the Sierra Fund’s Reclaiming the Sierra 2015 conference. Throughout the research studies, we are focused on identifying plant species that are native to this area that show sufficient growth in contaminated soils as well as have phytoremediation capacity. Results will inform future restoration and re-vegetation efforts of historic mining sites.