A program is underway in Italy to identify construction materials with high radioactivity contents and to evaluate the resulting indoor exposure on a nationwide scale. Building materials surveyed include those of natural origin and those employing particular by-products such as fly ash and phosphogypsum. The survey currently emphasizes natural building materials, which are widely used in many areas having particular geological features. First results show that Italy includes areas of high natural background, i.e. in Lazio and Campania, in which very high levels of indoor exposure occur that can be directly related to specific activities of the building materials. Moreover, 220Rn daughters are sometimes present at such levels that their contribution to the lung exposure is comparable to that from 222Rn daughters.

Existing data on 210Pb in human teeth are reviewed for various countries. The mean value of 210Pb in the teeth of population groups exposed to "normal" levels of radon-daughter exposure is about 2 mBq/g. A detailed analysis of 48 samples from a "normal" Italian population group revealed that smoking habits and age may have some influence on 210Pb content of teeth, while this is not the case for differences in sex. A group of 45 Austrians exposed to elevated levels of radon and radon daughters is compared with the Italian group. After subtraction of background levels of 210Pb as found for the normal Italian population, the incremental 210Pb tooth content due to excessive radon-daughter exposure has been correlated with the individual cumulative exposure corrected for background radon-daughter exposure. A statistical analysis shows the significance of the linear correlation at the alpha = 0.01 level. For the incremental increase of 210Pb in teeth, a value of 1.2 mBq/g has been used for a lifetime exposure to 1 WLM. This result is compared to corresponding data published in the literature, which are predominantly related to the 210Pb content of bone after short-time exposure at high levels, e.g. in uranium mines. The comparison seems to indicate the influence of the exposure rate and the need for a comprehensive model, which takes into account radon-daughter inhalation, radon dissolved in body fluids and 210Pb metabolism.