Low-dose radiation has small but measureable long-term risk

Nature : A study of 300 000 nuclear-industry employees from France, the UK, and the US has provided the first clear look at the risks of low-dose ionizing radiation. The researchers obtained exposure records dating back 60 years for employees who worked in the industry for at least one year while wearing a dosimeter. The researchers then followed up to track mortality from leukemia, lymphoma, and multiple myeloma. The study revealed that on average the workers received 1.1 mSv per year above the average yearly background radiation, which is about 2–3 mSv. As the amount of radiation exposure increased, there was a linear increase in the rate of leukemia as well. Similar patterns for other cancers were not statistically significant. Instead of the 134 deaths expected from leukemia, the researchers found there were 531. And while none of those deaths occurred in any employee who received less than 50 mSv of radiation, the linear extrapolations suggest that every 10 mSv of radiation exposure increases the risk of leukemia by 0.002%.