Enhanced frequency of micronuclei in lymphocytes from current as opposed to former uranium miners

Micronuclei can be used as markers of past radiation exposure,but few pertinent studies have dealt with alpha radiation. here we report on micronuclei in lymphocytes from uranium miners,comparing some that are currently active and others that retired 15-20 years ago. their radiation exposure is assumed to come mainly from radon and its decay products in the air breathed at the work place. current miners showed a greater micronucleus frequency than former miners. this can be attributed to their recent radiation exposure,while the lower frequency in the former miners probably results from the disappearance of potentially micronucleus containing lymphocytes from the peripheral blood,which is known to occur with a half-life of about one year. for current miners there is a significant correlation between micronucleus frequency and effective dose received over the last 12 months. the dose at which a doubling of the micronucleus frequency is observed is around 10 msv. this is a much smaller dose than would usually be expected to be detectable with this test,and raises a number of questions about the induction of micronuclei by alpha radiation from radon and its decay products.