THE white blood cells of workers at the Sellafield nuclear plant who have
inhaled plutonium dust have damaged chromosomes. That’s the conclusion of a
study funded by British Nuclear Fuels (BNFL), which runs the plant.
A team at BNFL’s Westlakes Research Institute in Cumbria found that 24
workers who had inhaled plutonium dust had more than twice as many broken
chromosomes in their lymphocytes as controls with little or no exposure to
plutonium. The workers, most of whom have levels of plutonium in their bodies
below the international safety limit of 1480 becquerels, also had twice as many
chromosome breaks as they did 10 years ago (Radiation Research, vol 150, p 459).
The Westlakes team suggests that the breaks are caused by alpha particles and
first form in the precursor cells in bone marrow that divide to form white blood
It’s not clear whether the workers have a higher risk of developing
leukaemia. Jan Tawn, a member of the team, says this is unlikely as the
mutations that cause the disease originate in stem cells deeper in the bone
But other experts aren’t so sure. Eric Wright of the Medical Research
Council’s Radiation and Genome Stability Unit in Harwell, Oxfordshire, fears
that mutations in precursor cells could lead to myeloid leukaemia, a form of the
disease that has been linked to radiation exposure.