Plutonium levels near Devonport spark call for more testing
Levels of radioactive plutonium found near a nature reserve in Devon have led to calls for increased monitoring.
Kinterbury Gate, near Devonport naval dockyard, has shown sharp spikes of plutonium and americium since 2007, Food Standards Agency reports show.
A senior scientist at Plymouth University said more investigation was needed into how the potentially cancer causing materials got into the water.
The Environment Agency said the "trace" amounts were no risk to public health.
Nearby Kinterbury Creek is designated as a County Wildlife Site "because of the interest in its maritime habitats" according to Plymouth City Council's website.
The materials found, plutonium 239 and 240 and americium 241, do not occur naturally in the environment and are by-products of nuclear energy plants, said Emeritus Professor Geoff Millward, director of the radiation analysis unit at Plymouth University.
"There should be absolutely no mystery about the origin of these alpha-emitting radionuclides, it should be known," he added.
FACTFILE: PLUTONIUM AND AMERICIUM
- Plutonium is used in the production of nuclear weapons and, like americium, is a by-product of nuclear energy plants
- Plutonium is best known as the main ingredient of atomic bombs
- Plutonium and americium are highly toxic to humans if ingested
- They are called "alpha emitters" like polonium which killed Russian spy Alexander Litvinenko
The Environment Agency said the spikes, shown in the Food Standard Agency's annual Radioactivity in Food and the Environment (RIFE) reports, were "most likely" due to a change in the government agencies that collected and analysed the samples in 2007.
And it said the "trace amounts" found at Kinterbury "are most likely to have originated from spent fuel reprocessing elsewhere" and "not related to activities or discharges" from Devonport, where Britain's nuclear submarine fleet is serviced.
The quantities of the radioactive materials found at Kinterbury, measured in radiation units or Becquerels per kilo (Bq/Kg), are well below levels found in other parts of the country such as Eskmeals near Sellafield nuclear power plant where 720 Bq/Kg of plutonium and 1,600 Bq/Kg of americium were found in 2014, according to the latest RIFE report.
Dr Jill Meara, director of Public Health England's (PHE) Centre for Radiation, Chemical and Environmental Hazards, said: "There is nothing we have seen in these reports that lead us to believe that recorded levels of discharges of radionuclides to the UK environment pose a threat to public health - technology allows the measurement of radioactivity in the environment at levels far below those that would cause public health concerns."
ANALYSIS: JOHN LARGE, NUCLEAR ENGINEERING CONSULTANT
There should not be any plutonium (Pu) or americium sources at Devonport unless, that is, there has been some historic spillage at Bull Point and/or the old Saltash nuclear warhead stores, both of which have been out of commission for years.
Similarly, there might have been a spillage from the clean-up operations under way at the Winfrith nuclear plant in Dorset, although most of this decommissioning programme should have been completed several years back.
It could have been a leak from the French nuclear power plant at la Hague or an incident at sea.
Nuclear powered submarine reactors do not generate much Pu, and if it derived from an incident involving a nuclear warhead then to breakdown the Pu a relatively energetic event, ie fire would be expected to have occurred.
Dr Jill Meara, director of Public Health England's Centre for Radiation, Chemical and Environmental Hazards, said it was unaware of "any information which suggests radiation levels detected in the Tamar River pose a risk to public health".
A Plymouth City Council spokesperson said the Environment Agency and Public Health England were "very clear" and "levels of radioactive material do not pose a threat to public health".
A Ministry of Defence spokesperson said it welcomed the monitoring by the Environment Agency and "doses to members of the public in the Devonport area are very low and absolutely safe".
An Environment Agency spokesman added: "The levels of plutonium and americium in the water are very low and there is no increasing trend.
"There is no link between operations at Devonport naval dockyard and the monitoring results.
"The test results are provided to the Food Standards Agency, forming one element of the RIFE report."