A new method specifically designed to expose cells isolated in vitro to radon and its decay products.

A system was set up to provide direct exposure of cells cultured in vitro to radon and its decay products. Radon gas emanating from a uranium source was introduced at a measured concentration in a closed 10-m(3) exposure chamber. Cells were cultured on the microporous membrane of an insert that was floating over the culture medium in a six-well cluster plate.

Influence of exposure rate on lung cancer induction in rats exposed to radon progeny.

Animal studies were used in addition to epidemiological studies to investigate the effects of exposure, exposure rate and other factors in predicting risks resulting from exposures to radon progeny. A trend toward increasing tumor risk with decreasing exposure rate was observed in rats exposed at a cumulative exposure varying from about 0.72 J h m(-3) (200 WLM) up to 10.