The levels of mercury in fish from Owyhee Reservoir ranged between 0.65 - 1.77 ppm. Since mercury collects in edible portions of fish tissue, the only way to limit exposure is to reduce the amount of fish eaten from contaminated waterways. Therefore, OHS warns that pregnant women, nursing women and children up to 6 years of age should not consume any fish from this body of water. Children older than 6 years and healthy adults should limit their consumption of fish from Owyhee Reservoir to no more than one-half pound (eight ounces) of fish six times a year (approximately one meal every other month). The U.S. Environmental Protection Agency is currently reviewing this health standard.
The source of the mercury appears to be from natural geological mercury in the rocks and soils in this area, and possibly, past mining activities. Additional fish sampling surveys will be conducted by DEQ and Oregon Department of Fish and Wildlife (ODFW) to further characterize the extent of mercury contamination.
Because sport fishing is a popular activity at Owyhee Reservoir, OHS and ODFW suggest that fishermen practice catch-and-release fishing. A catch-and-release approach allows fishermen to still enjoy fishing as a high-quality recreational experience, according to ODFW officials.