When commenting on your recent news report on radiation being found locally, Mr Dry asks of Marconi "How do they know?" that the level of radiation, and its danger, is low (Letters, June 13).

Perhaps, he should respect the extensive scientific knowledge that there is of tritium, rather than showing his obvious lack of scientific understanding by relying on quotes out of context from his dictionary, thereby providing meaningless details.

Further, Mr Dry alludes to "conflict with all medical evidence on the subject" but fails to provide any reference to what he actually means by this, or what sources he is quoting.

It seems strange that he has access to wide-ranging and deep "medical evidence," yet his only chemical reference is his dictionary.

I trust that the Borehamwood & Elstree Times aims to providea balanced view, and realises that the term "radiation" incites concern amongst readers, largely due to extensive misunderstanding of radiation as a subject.

Quoting from Greenwood & Earnshaw, Chemistry Of The Elements, a standard degree reference: "Tritium is a low-energy beta emitter with no associated gamma rays. The radiation is stopped by 6mm of air or 6 micro-meters of material of density 1 g/cm3 (eg water).

"Tritium is one of the least toxic of radioisotopes and shielding is unnecessary."

Indeed, tritium is used regularly as a tracer, ideal for autoradiography, and to allay concerns about the water table: "Tritium has been used extensively in hydrological studies to follow the movement of ground waters" (Greenwood & Earnshaw).

Having trained as a chemist, I find Mr Dry's implication that I am a "goon" insulting, especially when he clearly illustrates a lack of understanding of the subject matter.

I hope that the details provided here might help people sleep more soundly in their beds once more.

I would like to point out that I have absolutely no connection with Marconi, working as I do in the media industry. I write out of concern of the mis-representation of scientific issues.

Richard Sillitto

BSc (Hons) Chemistry, York

June 19, 2002 16:30