Starting in 2009, The Sierra Fund has conducted surveys of people fishing at regional water bodies, to learn whether they are being exposed to mercury from eating locally caught fish.
Survey results were originally published in 2011; the full report is available here, and a 2-page executive summary is also available. Additional surveys have been collected since that time, and an update of the report coming soon!
Millions of pounds of mercury were used in California’s Sierra Nevada’s during the Gold Rush. Much of it was lost to rivers, lakes and streams where it remains today.
Mercury is a danger to humans, especially when they eat fish from areas with mercury pollution. Mercury exposure from eating contaminated fish can cause developmental delays in children—this is why children younger than 18, women of childbearing age, and pregnant women need to avoid eating fish high in mercury.
There is limited information available to local fishermen about mercury levels in fish, despite health warnings issued by the State of California regarding the eating of fish at nearly every water body that has been tested.
In an effort to assess awareness about mercury exposure from fish in areas with historic mercury pollution, The Sierra Fund conducted a survey of local fishermen. Trained interviewers went to popular fishing spots in the Deer Creek, Yuba, Bear and American River watersheds, and asked fishermen a series of questions about how much fish they ate, what kind, and whether they were aware of any warnings about eating fish.
Most of the fishermen ate fish that was locally caught. Many reported feeding that fish to children under 18, women of childbearing age, and to a lesser extent, pregnant women.
The most popular fish eaten were bass and trout, and bass is a species that typically has the highest levels of mercury. As a result of high mercury contamination, bass are the subject of fish consumption advisories at many Sierra water ways, and at lakes and reservoirs throughout California.
There were no posted warning signs for mercury exposure at most of the survey locations. Instead, the fishermen who answered our survey said they got health information they really trusted from their doctors. This is important because the clinics we contacted in the Sierra did not report providing information on the dangers of consuming mercury-contaminated fish, not even to their pregnant patients.
Based on the results of the survey, The Sierra Fund suggests that signs with information about mercury in fish be posted where people fish, including both state-issued safe eating guidelines, and general information about mercury. Ideally, legacy mine sites need to be remediated to reduce overall mercury in the environment.
Angler Survey Full Report – The Sierra Fund’s full 85-page report covering survey questions, methods, locations, all results and recommendations
Angler Survey Executive Summary – A 2-page summary of The Sierra Fund’s survey report, including key findings and recommendations
OEHHA Fish Consumption Advisories – State-issued fish consumption advisories for lakes, reservoirs and rivers in California from the CA Office of Environmental Health Hazard Assessment
TSF’s Project to Post Fish Consumption Advisories – An annual volunteer-powered event to post state-issued fish consumption advisories at Sierra reservoirs
Environmental Health Outreach – The Sierra Fund’s campaign to bring information about public health exposures to legacy mining toxins to rural Sierra communities, and the doctors and nurses who serve them
Mercury Trainings for Healthcare Professionals – The Sierra Fund’s program to educate regional doctors about mercury in the human body, and how to talk to their patients about eating fish