The Nycomed Amersham plant near Cardiff makes radioactive isotopes for the pharmaceutical industry. It is Britain's second largest emitter of radioactive pollution after the British Nuclear Fuel's Sellafield reprocessing plant and has been the target of environmental protest for years. A report commissioned by the local Bro Taf Health Authority found that levels of birth defects 2 - 7km around the plant were 20% higher than would be expected.

Despite the above, the fact that tritium levels in flounders in the Severn Estuary doubled 1999-2000, and that traces of tritium and carbon-14 had been found in local fruit and vegetables, Bro Taf Health Authority and Nycomed Amersham denied any firm evidence of a link.

US scientists were very concerned that radioactive pollution from nuclear testing at its Nevada Test site 1956-92 might soon contaminate the well water in Beatty, a town of 1,500 people in the nearby Oasis Valley.

Before the tests were carried out, conventional geology supposed that underground water barely moved, and that radioactive particles would be sealed into cavities by the blast. Not so. They have now discovered that radioactive particles like long-lived plutonium-239 can travel in water, and that the groundwater is flowing more rapidly than predicted by 1950’s guesswork.