Women living downwind from nuclear power plants are at five times greater risk of developing breast cancer, experts have warned.
In three separate studies, a team of scientists looked at the rates of various cancers in populations living close to Trawsfynydd power station in North Wales, Bradwell in Essex and Hinkley Point in Somerset.
They discovered breast cancer rates, in particular, were higher than expected national averages at all three sites.
At Trawsfynydd, rates of the disease were five times greater than average, while in Essex and Somerset women had double the risk of developing breast cancer.
The research, supervised by Dr Chris Busby, who was previously based in Aberystwyth but is now attached to the Latvian Academy of Sciences in Riga, also found other types of cancer were recorded at double the rate in Trawsfynydd.
The Welsh plant is the only nuclear power station built inland in the UK.
It acts as a cooling water source and is also a sink for radioactivity released from the plant.
A significant amount of radioactive material exists in the lake bed sediment.
The power station ceased operation in 1993 but has yet to be fully decommissioned.
The prevailing winds at the site are south westerly and more than 90 per cent of those living downwind of the power station were surveyed by researchers working for Dr Busby.
The paper, published this month by Jacobs Journal of Epidemiology and Preventive Medicine, states: ‘Trawsfynydd is a “dirty” nuclear power station.’
‘As it has carbon dioxide, gas-cooled graphite block reactors, its releases into the air are higher than most other types of nuclear reactor.
‘In addition, all the liquid releases are discharged to the lake, where they have accumulated to the lake body sediment,’ the researchers noted.
‘Results show very clearly that the downwind population has suffered because of these exposures.
‘This is most clear in breast cancer in the younger women below 60, where the rates were almost five times the expected.
‘Additionally we see a doubling of risk in those who ate fish from Trawsfynydd lake, which supports the conclusion that it is mainly a nuclear power station effect that is being seen.’
Other forms of cancer showing elevated levels included prostate, leukaemia, mesothelioma and pancreas.