From Mark Shilton
I just had to comment on your short article describing the leakage of 20
tonnes of radioactive water from the Tsuruga power station
(24 July, p 25).
The figure of 46 000 becquerels in 20 tonnes of water sounds similar to the normal
concentration of radioactivity I would expect in ordinary groundwater in some
regions of Cornwall or Scotland.
The British “standard man” as defined by the National Radiological Protection
Board contains 4166 becquerels of natural potassium-40. This is about a tenth of
the radioactivity you reported had leaked from the Japanese reactor. I reckon
there would be more radioactivity in the team of safety workers cleaning up the
spillage than there was in the spillage itself.
Aston Clinton, Buckinghamshire
