Assessment of WL-values and their correlation with the resulting dose-rates to lung tissue:
The radioactive noble gas radon and its decay products (daughters) are known to be inducers of lung cancer among uranium miners. Also, there is strong evidence from epidemiological studies and experiments on rats that there is a synergistic effect between radon and tobacco smoke (by active or passive smoking) as well as to radon (being present in indoor air in practically every building). The radon problem has been recognized as being a potential health risk to all members of the general population.
The following questions need to be addressed.
What is the usefulness of the WL-level of inhaled air in estimating the dose-rate to the lung, and which other physical or biological parameters might possibly be of importance? We wish to carry out radon inhalation experiments on rats in which the dose-rate to the lungs is determined by killing rats immediately after radon exposure and measuring the resulting activity in the lungs and other tissues. This will be done for different exposure conditions (by TNO and by LPP, Razes, respectively) by varying parameters like the composition of inhaled activity (ie different ratios of daughter concentrations), aerosol conditions and breathing rate of the animals.
By which measuring procedure can WL-levels best be determined? This should involve careful examination of some methods used in laboratory and mining practice, like the Thomas method, the Rolle method and the Lucas method. Their reliability should be tested under different conditions as the way of air sampling seems to be very important.
This may lead to recommendations on WL-measurements in the future, and to a reevaluation of WL-values available at present.
Funding SchemeCSC - Cost-sharing contracts