An assessment of the environmental radiation dose for residents of the Perth metropolitan area

The total environmental radiation dose for residents of the Perth Metropolitan Area is assessed. This dose is assumed to come from a variety of sources, including Rn(222) and Rn(220) progeny, background gamma radiation, radioactivity of building materials and radioactivity in drinking water. Based on the results of measurements of these sources, the average total estimated annual effective dose equivalent for residents of the Perth Metropolitan Area is 3.5 mSv. This is considerably more than the public limit for artificial sources ( 1 mSv) recommended by the ICRP. Nearly 50% of the average total dose comes from indoor Rn(222) and Rn(220) progeny with Rn(222) progeny contributing 31% (1.1 mSv) and Rn(220) progeny 17% (0.6 mSv) of the average total dose. Background gamma radiation contributed 35% (1.2 mSv). Radioactivity of local building materials contributed approximately 13% (0.4 mSv), while radioactive isotopes in groundwater contributed only 3% (0.1 mSv) to the average total annual effective dose equivalent respectively. 30 refs., 5 tabs