MERCURY IN SPORT-CAUGHT FISH FROM OWYHEE RIVER

November 27, 1996

Contacts:   Dave Stone, Environmental Specialist, 503-731-4012
  Ray Huff, Malheur Environmental Health, 541-473-5186

FOR IMMEDIATE RELEASE

ELEVATED LEVELS OF MERCURY IN SPORT-CAUGHT FISH FROM OWYHEE RIVER UPSTREAM FROM OWYHEE RESERVOIR, MALHEUR COUNTY

PORTLAND: The Oregon Health Services in cooperation with Malheur 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 Owyhee River upstream of Owyhee Reservoir and downstream of Three Forks. There have been similar advisories for several years affecting Owyhee Reservoir, Jordan Creek and Antelope Reservoir in the same general area. Those advisories continue in effect and this new advisory is added to them. The advisory recommends specific limits on the amount of fish eaten from the river itself, through a stretch of about 80 miles from the reservoir upstream to the Three Forks area.

Today's release is based upon mercury tests of edible fish tissue from Owyhee River fish beginning in 1969 and 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 on a regular basis. The advisory aims to prevent brain and nerve injury to fetuses, infants and small children; and to protect adults who eat large amounts of fish from injury to their kidneys, livers and nervous systems.

The average level of mercury found in sport caught fish from the affected portion of the river, they said, is 0.54 parts per million. The recommended consumption limits in the advisory are calculated to protect consumers of these fish from any known harmful effects due to mercury.

The recommended consumption limits are as follows:

1. Children six years of age and younger should not eat more than one 4-ounce fish meal every six (6) weeks;
2. Children older than six years and women of childbearing age, especially if they are pregnant or nursing, or if they plan to become pregnant should not eat more than one 8-ounce meal of fish every three (3) weeks; and

3. Women past the age of childbearing and all other healthy adults may safely eat as much as one 8-ounce meal of fish every (5) days.

The source of the mercury in the Owyhee basin is thought to be natural volcanic and geothermal deposits in the drainage area, possibly influenced by historical mining practices in parts of 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.

Generally in Oregon lakes, reservoirs and rivers squawfish and largemouth bass appear to have higher body loads of mercury than fish of other species. Persons who regularly consume fish of these two species should be very careful not to exceed recommended limits. Large fish of any species should be expected to contain higher levels of mercury in their tissues than smaller fish of the same kind.

Anglers are encouraged to practice catch-and-release fishing, especially for larger specimens of any species. (See Oregon fishing regulations book for instructions about releasing 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, the Health Services encourages catching and eating fish from Owyhee River so long as consumption does not exceed the levels recommended in this advisory.