The Oregon Health Authority is issuing recommendations on the amount of lamprey from the Columbia River and its Oregon tributaries that people should eat.  Fish tissue data from the Columbia River Inter-Tribal Fish Commission show polychlorinated biphenyls, or PCBs, at levels of concern in lamprey for the general population, and for PCBs and mercury for vulnerable populations, including children under 6 years old, people who are or may become pregnant, and nursing mothers.  OHA issues advisories when fish or shellfish tissue data show that the levels of contaminants — in this case, PCBs and mercury — are high enough to potentially harm health.  The OHA recommends the general population limit whole body meals of lamprey to four per month in the general population and two per month for those in vulnerable populations.