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

Abstract

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 and that 7% of schools exceeded 500 Bq m, 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.

Radon Spatial Variations in University’s Buildings Located in an Italian Karst Region

“…Both surveys show values of annual Rn much higher than the value of 52 Bq/m 3 (AM) estimated for Puglia region in [22]. The karstic nature of the province of Lecce could be responsible for higher Rn values due to the high permeability of the soil and the high number of faults and cavities that facilitate the radon transport [4,17,23].…”

“…Moreover, a radon campaign carried out in 500 schools in Salento highlighted the presence of high indoor radon activity concentrations in areas characterized by the presence of a complex karst substrate associated with a rather irregular alternation of both calcareous and calcarenitic lithotypes and clayey deposits [15,16]. The radon remediation actions adopted in several schools allowed to observe how, in the case of buildings located in karst area, typical radon reduction interventions may sometimes be less effective [17]. Recently, in the same region, a new radon survey has been carried out in the buildings of UniSalento University in order to evaluate the variations of indoor radon concentrations in a high number of buildings placed in a restricted area and different by year of construction, materials used, type of fixtures, type of heating system, and building size.…”

Effectiveness of passive ventilation on radon indoor level in Puglia Region according to European Directive 2013/59/EURATOM

“…24 Because of the peculiar soil geology, building materials, ventilation design and occupants' behaviour, identifying the most effective remedial action is complex without on-site measurements. 25 In this study, a simple, cheap and effective remedial action was selected to reduce the high concentration of indoor radon: passive ventilation through opening the windows. 26 A first short-term measure lasting one week was performed using short-term electrets in combination with chamber (SST configuration) 27 in order to verify the value of the concentration of radon gas obtained in 2013.…”

Indoor Radon Exposure in Italian Schools

“…Based on the increasing body of evidence on the relationship between radon levels and chronic diseases, radon concentrations should be routinely monitored where individuals live or work. In particular, as underscored by several studies [ 4 , 5 , 6 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ], attention should be focused on schools, where students, teachers, and other personnel spend numerous hours daily. Apart from the long exposure to elevated radon concentrations, several concerns should be raised regarding the potential high vulnerability of some population groups, such as children.…”