Native Americans who fished in the Columbia River may have been exposed to much more radiation from the Hanford Nuclear Reservation than previously thought, according to a draft report prepared for the federal government. Earlier research estimating the exposure rates for people living downwind of Hanford assumed that people ate about 90 pounds of fish per year during the 1940s and ’50s when radioactive iodine contaminated fish. But the new research suggests that members of tribes along the Columbia may have been eating more than 500 pounds of fish per year.