A survey on natural radioactivity in schools of South-East Italy

During the years 2005 and 2006 a survey on natural radioactivity in about 500 schools located in South-East Italy (the Salento peninsula, province of Lecce) has been carried out. In particular average radon concentration and average absorbed dose rate in air due to gamma radiation have been assessed by using solid state nuclear track detection (SSNTD) and electret dosimeters, as well as TLD dosimeters, respectively. SSNTD dosimeters were placed in each school, while electrets and thermoluminescence dosimeters (TLD) were added in a selected sample of 56 schools. Moreover during the second semester, in each of 56 schools, two electret dosimeters with the same configuration were placed, in order to assure the quality in data production - as homogeneity and reliability. In this paper final results related with the measurements performed in a selected sample of schools are reported. The indoor radon levels measured in the schools ranged from 61 Bq/m3 to 1326 Bq/m3, and only six schools showed Rn concentration values over 500 Bq/m3, Italian action level for workplaces. As for the average absorbed dose rate in air due to gamma radiation, the recorded values ranged between 0.41 and 0.73 mGy/y with an average value of 0.57 mGy/y. (author)