Double exposure

摘要

Nuclear regulators have miscalculated the health risks from one of the world's most widespread nuclear pollutants. People are twice as likely as previously thought to develop cancer after being exposed to tritium spread in hydrogen bomb tests and discharged by nuclear plants and factories. The risks remain low, as doses are still well within international safety limits, say British regulators. But radiation experts insist that the oversight is worrying, and that people who eat fish from contaminated waters may have received much higher levels of radiation than supposed. Vast amounts of tritium, an isotope of hydrogen, were released into the atmosphere by nuclear weapons tests in the 1960s. Thousands of trillions of becquerels are still emitted each year by nuclear plants at Savannah River in South Carolina, Sellafield in Cumbria and Chapelcross in southern Scotland.