100 kBq m-3 Radon Activity Concentration in the Atmosphere of a Bathroom Supplied with Groundwater From A Gneissic Rock Area with Consanguineous Intrusions.

Inhalation of escaping radon from groundwater comprises the largest part of radiological hazard from groundwater radionuclides in the uranium and thorium series. Groundwater containing 1.5 mg dm uranium and 3 kBq dm radon activity concentration supplied an ordinary bathroom of 15 m in a home. Using the showerhead, atmospheric levels of radon activity in the bathroom exceeded 100 kBq m within a period of about 1 h.