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Dead careless

Dead careless

作者:漆救疤  时间:2019-03-08 09:08:01  人气:

By Rob Edwards EXPOSURE to the radioactive isotopes used in medicine and industry can, in extreme cases, lead to leukaemia within a few months, warn scientists in Russia and Britain. The discovery adds to growing concern about procedures for handling radioactive sources in the workplace. It comes shortly after a senior official of the International Atomic Energy Agency (IAEA) accused the agency of failing to protect workers from millions of the radioactive sources used in factories, hospitals and laboratories around the world. A study by the Institute of Biophysics in Moscow and the National Radiological Protection Board (NRPB) in Didcot, Oxfordshire, found signs of leukaemia in the blood of a man just five months after he was first exposed to a portable radioactive source (Radiation Protection Dosimetry, vol 81, p 85). The man, an unnamed Russian, had been driving about with unshielded caesium-137 in the door of his truck. The isotope, thought to be from an industrial gauge, was emitting 48 gigabecquerels of radioactivity. When the man was admitted to hospital in Moscow in July 1995 with fatigue and hair loss, doctors noticed that he had up to 35 times the normal levels of the immature white blood cells known as band neutrophils. At first they thought this was a sign that his bone marrow was starting to recover from the radiation exposure, but 15 months later he was diagnosed with leukaemia. He died in April 1997. David Lloyd of the NRPB, one of the paper’s authors, says that the raised levels of neutrophils now appear to have been an early indication of cancer. “It is a unique and very instructive case,” he says. The Russian case is exceptional, but experts in radiation protection are worried about blasé attitudes to the dangers posed by radioactive sources. Abel Gonzales, the radiation safety director of the IAEA, has accused the agency of having an “apparent lack of interest” in the hazards of radioactive sources in the past. In place of genuine guidance, it had offered no more than “motherhood and apple pie”, he said at a conference in Dijon, France, in September. Since 1986, at least a dozen deaths have been caused by the mishandling of similar radioactive sources. They include four people contaminated by a medical isotope in Brazil, a man who stole a caesium-137 source from a scrap yard in Estonia, and a soldier exposed to a source left in Georgia by Soviet forces. The IAEA says that as many as 110 countries lack a proper system for licensing and inspecting the radioactive sources used in industry and medicine. Fifty of those are members of the IAEA, and the agency is working with them to establish safeguards by the end of 2000. It can do nothing, however,