March 8.When Sir Douglas Black investigated the Sellafield leukemias,

he found that, according to his information on cause and effect,

Sellafield discharges had been too small to cause such a gross anomaly

in cancer statistics. Of course, the estimates of Sellafield discharges

were wrong -- but Sir Douglas, like the rest of us, only found this out

several years later.

The International Commission on Radiological Protection continually

reviews pathways of radioactive pollution and levels of exposure. New

pathways are constantly being identified. Levels of exposure are

continually reviewed and reduced. In fact it is almost universally

admitted now that any man-made addition to radiation exposure will have

a detrimental effect on the environment and health in general -- cancer

statistics in particular.

The ICRP has recently reviewed its estimates of ''take-up'' rates of

radioactivity. Now it tells us that we absorb much more plutonium, et

al., from the environment and consumption of food, water and air, than

it used to believe. In other words, we are much more sensitive to

Sellafield, Dounreay, Chernobyl, and nuclear waste than previously

thought.

Dr Robert Wheaton and Professor Murdoch Baxter have demonstrated the

fallibility of official monitoring. Chernobyl proved the point.

Now -- while BNFL is still reeling from the implications of the

Gardiner report, and the ICRP confirms even worse possibilities -- the

British Government continues to sanction reprocessing of nuclear

discharges which would be illegal anywhere else in the world.

Worst of all, Mrs Thatcher defies Europe by planning to dump nuclear

waste under the bed of the North Sea -- among the oil-rigs!

Are we mad?

Frances McKie,

Snowberry,

East Road,

Kirkwall,

Orkney.