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ELEVATED LEVELS OF MERCURY IN SPORT-CAUGHT FISH FROM THE SNAKE RIVER
April 28, 1997
Contact: Bonnie Widerburg, 503-731-4180
Technical Contact: Dave Stone, Environmental Specialist, 503-731-4012
(PORTLAND) The Oregon Health Services, in cooperation with other concerned state agencies, is advising the public today of elevated mercury levels in the meat of fish caught in the Snake River on the Oregon border. The advisory extends from the Oregon/Washington border southward to where the river enters Idaho below the town of Adrian. The advisory recommmends specific limits on the amount of Snake River fish that can be safely eaten.
Today's release is based upon mercury tests of edible tissue from Snake River fish from 1969 to the present, as well as test results from Brownlee Reservoir from 1989 continuing to the present time. Ken Kauffman of the Environmental Toxicology section of the Oregon Health Services said the mercury levels are sufficient to pose chronic health concerns especially for susceptible persons who consume fish from the river or reservoir on a regular basis. The advisory aims to prevent brain and nerve injury to fetuses, infants and small children in particular; and to protect adults who eat large amounts of Snake River fish from injury to kidneys, livers and nervous systems.
The average level of mercury found in fish from the Oregon portion of the Snake River and Brownlee Reservoir, they said, is 0.41 parts per million. The Health Services issues public advisories when the average mercury level in tissue exceeds 0.35 ppm. The recommended limits in the advisory are calculated to protect consumers of these fish from any known harmful affects due to mercury.
The recommended limits are as follows:
- Children six years of age and younger should not eat more than one 4-ounce fish meal every month
- Women of childbearing age especially if they are pregnant, nursing or are planning to become pregnant should not eat more than one 8-ounce meal of fish every two and one half (2.5) weeks
- Women past the age of childbearing, children older than six years and all other healthy adults may safely eat as much as one 8-ounce meal of fish every five (5) days or six meals per month
The advisory applies to all native species in the river whether caught above or below Hell's Canyon dam, but does not apply to steelhead because they spend very little time in fresh water streams.
The mercury in the fish is thought to be from natural volcanic and geothermal sources in the upper drainage areas, possibly influenced by historical mining practices in the watershed. Once mercury enters the food chain it bioaccumulates and is not likely to diminish or disappear from organisms in the river. The Health Services, Department of Fish and Wildlife, and the Department of Environmental Quality continue to monitor contaminant levels and will update the advisory if significant changes occur.
Persons who regularly consume large specimens of any fish species should be especially careful to not exceed the limits recommended in this advisory. Anglers are encouraged to release larger, older fish rather than using them for eating. (See catch-and-release instructions in the Oregon fishing regulations manual.)
Mercury is bound in the muscle tissue of fish, so the exposure to consumers cannot be significantly reduced by cleaning, cooking, brining, smoking, canning or any other processing activities.
Because fish are an excellent source of nutrients for people of all ages, the Health Services encourages catching and eating of fish from the Snake River and Brownlee Reservoir so long as consumption does not exceed the levels recommended in this advisory.
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