222Rn in selected waters sources from Quang Nam - Da Nang region - Central part of Vietnam

This paper presents the radon concentrations of forty-eight samples collected from lakes, streams and rivers as surface water, from dug well as ground water and from boreholes and thermal waters as underground waters in the Da Nang - Quang Nam, central part of Vietnam. The measured radon concentrations varied from 0.265 (in lake water) to 107 Bq L-1 (in underground water) with the following trend from the lowest to the highest: Rn-222 in lakes<Rn-222 in rivers<Rn-222 in stream<Rn-222 in dug wells<Rn-222 in thermal waters<Rn-222 in drilled wells. Overall, the average Rn-222 concentration in groundwater is twelve times higher than that in the surface water.Assuming that each person drinks 2.10(-3) m(3) d(-1) and uses six cubic meters for washing purposes per month, the estimated total annual effective dose due to ingestion and inhalation of radon from the studied water samples ranges from 1.3 to 541 mu Sv y(-1) for adults; from 1.2 to 479 mu Sv y(-1) for children; and from 2.1 to 838 mu Sv y(-1) for infants.