Health risks

Particles vary in size and radioactivity. As a rule of thumb, the smallest particles are the least radioactive and therefore least hazardous, while the largest particles are the most radioactive and therefore most hazardous.

Expert laboratory research into the potential health effects of different particles has been carried out by the Health Protection agency for SEPA and studied by the independent Dounreay Particles Advisory Group. This work looked at the likely health effects of different particles being swallowed, inhaled or coming into skin contact. As a result, DPAG identified three categories for classifying particles according to their potential health effects:


• Significant –
Radioactivity greater than a million becquerels of caesium 137
Visible effects within a few hours if kept in stationary contact with skin; serious ulceration after 1-2 weeks

• Relevant -
Radioactivity of 100,000 to a million becquerels of caesium 137
Discernible effects after seven hours if kept in stationary contact with skin; reddening after 1-2 days

• Minor -
Radioactivity of less than 100,000 becquerels of caesium 137
No discernable health effects if kept in stationary contact with skin

The group concluded that only those particles in the significant category pose a realistic potential of causing harm to members of the public.

To date, significant particles have been found on the seabed and on the enclosed foreshore at Dounreay close to where historical sea discharges occurred.

Relevant particles have been detected on one beach used by members of the public and minor particles on this and another two beaches used by the public. No significant particles have been detected on any beach used by the public.

In its Third Report in 2006, DPAG concluded that the probability of the most frequent beach-users at Sandside coming into contact with a relevant particle is one in 80 million.

The risk to health from particles at these beaches is considered low, so public access is not restricted.
 

Summary table of finds
  Seabed Dounreay foreshore Sandside beach Dunnet beach Murkle beach
Significant Yes Yes No No No
Relevant Yes Yes Yes No No
Minor Yes Yes Yes Yes Yes
Restrictions in place Yes Yes No No No

 *A minor particle was detected on land adjacent to Dounreay in August 2009.

For more information about potential health effects, see the Third Report of Dounreay Particles Advisory Group.

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Image: A larger particle recovered from offshore

A larger particle recovered from offshore

Image: Monitoring the beach at Dunnet

Monitoring the beach at Dunnet

Image: Laboratory examination of a particle recovered from a beach

Laboratory examination of a particle recovered from a beach

Image: Aerial view of the beach at Sandside Bay, with Dounreay in the background

Aerial view of the beach at Sandside Bay, with Dounreay in the background