Reclaiming the Sierra

Like it or not: Mercury threat exists in Gold Country fish – response to the Union opinion column

June 11, 2013

The Sierra Fund’s fully referenced response to The Union 6/7/2013 guest column “Concern about mercury overblown

A recent opinion voiced by Robert S. Shoemaker in the Union newspaper deceptively stated, “Very small amounts of mercury have been found in fish” – he is correct about that, but it is also true that it takes only a very small amount of mercury (in the form of methylmercury) to poison a developing fetus in utero, resulting in permanent developmental disabilities.

If you are a pregnant woman, it is important to eat fish, which are an essential source of omega-3 fatty acids, but you need to choose fish that are lower in mercury, such as wild caught salmon.

The remainder of Mr. Shoemaker’s opinion was not just deceptive, but simply incorrect.  He proclaimed, “No one in the United States has ever been sick or died from mercury poisoning from eating any kind of fish.” The unfortunate truth behind the gold mining era is that mercury poisoning occurred prolifically amongst California gold miners in the 1850s and regrettably, continues to poison small-scale gold miners today in developing countries worldwide.

Numerous studies by universities, physicians, and government agencies have established the dangers posed by mercury that accumulates in the food chain, and how the consumption of too much high mercury fish poses a health threat.[1] Dr. Jane Hightower, a diagnostic physician in San Francisco, recorded numerous instances of methylmercury poisoning in California patients who consumed high mercury fish in the last decade.[2] The Office of Environmental Health Hazard Assessment (OEHHA) has issued several studies on the health threat posed by mercury in California fish, and issues fish consumption warnings for different fish species throughout California, all of which are available on their website.[3] The State Water Resources Control Board (SWRCB) also lists mercury-impaired water bodies and related studies on their website.[4]

The Yuba River watershed saw the greatest impacts from mining and mercury use in the state[5] and nearly every water body that has been tested here is listed as impaired due to mercury.  For some fish species such as rainbow trout, it may be safe to eat one or two servings per week, but bass and catfish often have a “Do Not Eat” warning.

It is important to note that some fish species have higher mercury content than others, and some reservoirs are of more concern than others. We encourage people to go to OEHHA’s website and the SWRCB website and look for your local fishing spots to find out if there are fish consumption advisories posted, or if that water body is listed as impaired due to mercury.  Not all water bodies have been sampled for mercury and therefore, may not have any warnings. When there is no local advisory present, the EPA recommends limiting sport fish consumption to one meal per week.[6]

The Sierra Fund (TSF) is committed to providing scientifically sound information about the risk of eating high mercury fish, particularly locally caught or “sport fish” found here in the Sierra. TSF is reaching out to different Sierra communities with a focus on educating high risk individuals, such as tribal people who may be subsistence fishing, as well as women who are or may become pregnant.

To get fish consumption advisories near you go to the SWRCB’s website at:   and click on your local water body to view the advisory.


[1] Some studies that indicate the danger of mercury in fish:

K. He, P. Xun, K. Liu, S. Morris, J. Reis, E. Guallar. 2013. Mercury Exposure in Young Adulthood and Incidence of Diabetes Later in Life: The CARDIA trace element study. Diabetes Care 36(6): 1584-9.

Dalgard C., P. Grandjean, P. J. Jorgensen, P. Weihe. 1994. Mercury in the Umbilical Cord: Implications for Risk Assessment for Minamata Disease. Environ Health Perspect 102:548-550.

Debes F., E. Budtz-Jorgensen, P. Weihe, R.F. White, P. Grandjean. Impact of Prenatal Methylmercury exposure on Neurobehavioral Function at Age 14 Years. 2006. Neurotoxicology and Teratology 28: 363-375.

J.L. Domingo, Omega-3 Fatty Acids and the Benefits of Fish Consumption: Is All that Glitters Gold? 2007. Environment International 33: 993-998.

L.R. Goldman, M.W. Shannon. Technical Report: Mercury in the Environment: Implications for Pediatricians. 2001. Pediatrics 108(1): 197-205.

M. Harada, T. Fujino, T. Oorui, S. Nakachi, T. Nou, T. Kizaki, Y. Hitomi, N. Nakano, H. Ohno. Followup Study of Mercury Pollution in Indigenous Tribe Reservations in the Province of Ontario, Canada, 1975-2002. 2005. Bull Environ Contam Toxicol 74:689-697.

J.M. Hightower, D. Moore. Mercury Levels in High-End Consumers of Fish. 2003. Environ Health Perspect 111(4): 604-608.

C. Monohan.  2011.  Gold Country Angler Survey:  A Pilot Study to Assess Mercury Exposure from Sport Fish Consumption in the Sierra Nevada.

E. Oken, J.S. Radesky, R.O. Wright, D.C. Bellinger, C.J. Amarasiriwardena, K.P. Kleinman, H. Hu, M.W. Gillman. Maternal Fish Intake during Pregnancy, Blood Mercury Levels, and Child Cognition at Age 3 Years in a US Cohort. 2008. Am J Epidemiol 15: 1171-81.

F. Shilling et al. 2010. Contaminated Fish Consumption in California’s Central Valley Delta. Environmental Research. 110(2010)334-344

[2] Hightower, Jane M. Diagnosis: Mercury: Money, Politics, and Poison. Washington, D.C.: Island Press, 2009.

[3] California Office of Environmental Health Hazard Assessment (OEHHA) Fish Consumption Guidelines are available online here:

OEHHA studies on mercury in California fish, and other reports at, include:

OEHHA, 2008, Development of Fish Contaminant Goals and Advisory Tissue Levels for Common Contaminants in Sport Fish: Chlordane, DDTs, Dieldrin, Methylmercury, PCBs, Selenium, and Toxaphene

OEHHA, 2006, General Protocol for Sport Fish Sampling and Analysis – This report was modified on 12/14/2006 to correct a typographical error on page 4 that created potential confusion regarding the size of fish in composite samples and the “75 percent rule.”

OEHHA, 2006, Draft document: Development of Guidance Tissue Levels and Screening Values for Common Contaminants in California Sport Fish: Chlordane, DDTs, Dieldrin, Methylmercury, PCBs, Selenium, and Toxaphene

[4] A list of California Lakes and Reservoirs impaired by mercury is available on the State Water Resources Control Board website here:

Additionally, an interactive map where you can look up impaired water bodies is available here:

Information on the State Water Resources Control Board’s ongoing efforts to address mercury in California’s water bodies is available here:

[5] California Department of Conservation, 2003, Abandoned Mine Lands Assessment of the North Yuba Watershed, available at

[6] The US EPA’s Fish Consumption Advisories Web site – This site provides general information on fish advisories, public information materials, technical guidance documents, and related links.  The Joint Federal Advisory on mercury and fish is available here: