Critical aspects of radon remediation in karst limestone areas: some experiences in schools of South Italy.

The final results of radon monitoring in 438 schools located in the province of Lecce (Puglia Region, South Italy) showed an average radon concentration of 215 ± 20 Bq m-3 and that 7% of schools exceeded 500 Bq m-3, the current Italian action level for radon in workplaces, and consequently required remedial actions. The activity described in the present paper includes the main elements of the remediation project in a subgroup of school buildings. The main radon control systems adopted were sub-slab depressurization (in 57% of schools) and the active ventilation of the crawlspace (in 21% of schools). This experience allows us to put in evidence relevant critical aspects, such as the influence of the karstic nature of the area, the optimization of remediation, the architectural constraints in the case of buildings of architectural or historical interest, which are discussion herein. Moreover, considering the new reference level for radon in workplaces introduced by the new EU Basic Safety Standards, a new analysis of data, achieved in the first survey, highlighted that 20% of schools need to be remediated.

Indoor radon levels in schools of South-East Italy.

A survey was conducted to evaluate average levels of indoor radon and gamma doses in all educational buildings (506 schools) located in South-East Italy (the Salento peninsula, province of Lecce). In this paper the final findings relating to measurements performed with SSNTD dosemeters in 438 schools (86% of the sample) are reported. The average annual activity concentration of radon in schools located in the province of Lecce is 209 ± 9 Bq/m(3). Radon values actually ranged from 21 Bq/m(3) to 1608 Bq/m(3). About 7% of schools showed radon concentration values above 500 Bq/m(3), the Italian action level for workplaces.

A pilot study on natural radioactivity in schools of south-east Italy.

In the period 2005-2006 a survey on natural radioactivity in about 500 schools located in south-east Italy (the Salento peninsula, province of Lecce) was 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 detectors (SSNTD) and electret ionization chambers (EIC), as well as thermoluminescence dosimeters (TLD), respectively. SSNTD dosimeters were placed in every school, while electrets and TLD have been employed in a pilot study performed in a selected sample of 56 schools in order to achieve preliminary information. Moreover the study foresaw a quality control on electret dosimeters' perfomances in terms of homogeneity and reliability. The results of this check have been taken into account in the data analysis. In this paper final results concerning the pilot study are reported. The indoor radon levels measured in the schools ranged from 65Bq/m(3) to 1808Bq/m(3), and only six schools (corresponding to 13% of the sample) showed radon annual average above 500Bq/m(3), Italian action level for workplaces. For the average absorbed dose rate in air due to gamma radiation, the recorded values ranged between 47 and 83nGy/h with an average value of 61nGy/h.