February 26, 1996. Copyright, 1996, Graphic News. All rights reserved

BECQUERELÕS LEGACY: A CENTURY OF RADIOACTIVITY
By Nicholas Booth, Science Editor

LONDON, February 26, Graphic News- A hundred years ago today (26 February), a 44-year old French scientist Ð a distinguished man with a flowing beard already tinged with white Ð began an experiment which would change the world in which we live. Henri BecquerelÕs aim was to see if crystals of uranium would leave their trace on a photographic film after being exposed to the Sun. But February 26, 1896 happened to be a cloudy day, so he placed the crystals and the film in a drawer until the clouds dispersed. Three days later, when he found the film fogged by the crystals, he realised he had made an important discovery.

Radioactivity, as BecquerelÕs finding was later christened, came as quite a shock. By the 1890s, scientists thought the atom was immutable and unchanging. The discovery of X-rays in 1895, followed by BecquerelÕs discovery and that of electrons a year later, totally changed the perception of the atom. It introduced uncertainty into a strictly clockwork notion of science, and only later was it realised that X-rays and electrons are part of the atomic emanations which are classed as radioactivity.

This week, many of the worldÕs most important scientists will meet in London to commemorate BecquerelÕs legacy at the Royal Society of Arts. To be opened on February 29 by Secretary of State for Environment, John Selwyn Gummer, the conference is designed to Ôillustrate the pervasive nature and beneficial uses of radioactivityÕ, for in the century since Becquerel made his discovery it has revolutionised our lives.

And yet radioactivity has always had a bad press, for there are many myths and rumours about the invisible rays which occur in nature and their effects are often misunderstood. 

Extremely low levels of radiation are emitted from buildings and from the EarthÕs rocks, and are found in the air that we breathe and in our food and drink. It is this natural emission to which most people are subjected, with negligible material effects. It is, of course, the use of uranium which has received most obvious attention, for the Curies classified many of the properties of radioactivity by examining uranium salts in detail. This was, alas, at great personal cost to themselves for they both died from leukaemia, probably contracted from handling the metal unprotected. 

The chemically-inert gas, radon, results from the breakdown of uranium and this itself produces unstable products which are potentially carcinogenic. (Radon accounts for the largest single source of the average personÕs dosage of naturally-occuring radiation). And in the mushroom-shaped legacy of its most powerful expression, the atomic bomb, radioactivity is indelibly associated with manÕs most fearful weaponry.

But far from being insidious, radioactivity is a tool which has innumerable uses in modern life. Be it the X-raying of metallic objects in airport security areas, the dating of archaeological artifacts or the triggering of smoke alarms by radioactive sensors, life without them would not be the same. And in the field of medicine, the tracing of medicines around the body, the targeting of diseased organs or tumours and their destruction, via radiotherapy, ensures that our lives are healthier than they would have been without BecquerelÕs discovery.

Source: National Radiological Protection Board, Royal Society of Chemistry, Amersham International

EDITORÕS NOTE: Becquerel started his experiment on February 26, 1896. His discovery of radioactivity took place on March 1, 1896. Please amend copy accordingly to your use.