ELEVATED LEVELS OF MERCURY IN SPORT-CAUGHT FISH FROM DORENA RESERVOIR IN LANE COUNTY
February 25, 1997

Contact: Bonnie Widerburg, 503-731-4180
Technical Contacts:
  Dave Stone, Environmental Specialist, 503-731-4012
  Stan Petrasek, Lane County Health Dept., 541-687-3731

(PORTLAND) The Oregon Health Services, in cooperation with Lane County Health Department and other affected state agencies, is advising the public today of moderately elevated mercury levels in the meat of fish caught in Dorena Reservoir, a man-made recreational reservoir in Lane County. The advisory recommmends specific limits on the amount of fish eaten from that reservoir.

Today's release is based upon mercury tests of edible muscle tissue from fish taken from the reservoir beginning in 1992 and continuing to the present time. Ken Kauffman, environmental toxicology section at the Health Services, said the mercury levels are sufficient to pose chronic health concerns especially for susceptible persons who consume fish from the 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 Dorena Reservoir fish from injury to their kidneys, livers and nervous systems.

Tests of edible muscle samples show an average level of 0.37 parts per million in the fish from the reservoir. 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:

• 1. Children six years of age and younger should not eat more than one 4-ounce fish meal every four (4) weeks;
• 2. Women of childbearing age, including pregnant females and breastfeeding mothers, should not eat more than one 8-ounce meal of fish every two weeks; and
• 3. Women past the age of childbearing, children older than six years of age and all other healthy adults may safely eat as much as one 8-ounce meal of fish every four (4) days.

The source of the mercury in Dorena Reservoir fish is thought to be natural volcanic and geothermal deposits in the upper drainage area. The movement of mercury into waterways and bioaccumulation may be influenced by historical mining practices in the watershed, but this subject has not been well studied. Once mercury enters the food chain it bioaccumulates and is not likely to diminish or disappear from organisms in the reservoir. 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.

Anglers are encouraged to practice catch-and-release fishing, especially for larger specimens of any species, since the older and larger the fish, the greater the mercury concentration is likely to be in the fish.

Mercury is bound in the muscle tissue of fish, so exposure to consumers cannot be significantly reduced by cleaning, cooking, brining, smoking, canning or any other processing activities.

Because fish is known to be an excellent source of nutrients for people of all ages, Health Services encourages fishing and eating of fish from Dorena Reservoir so long as consumption does not exceed the levels recommended in this advisory.