|An out-of-date publicity campaign... ...|
We cannot escape from radioactivity. Granite rocks are lightly radioactive owing to the presence of thorium, uranium and several of their radioactive descendants. A celebrated thermal source used this feature as an advantage when radioactivity was being cheered by the public in the 1930s. Seventy years on, another source from the same region prefers using the smile of the popular soccer player Zinedine Zidane superimposed onto the Auvergne mountains to proclaim the quality of its water. The low levels of radioactivity, however, mean that both waters are perfectly healthy.