Determination of radon exhalation from granite, dolerite and marbles decorative stones of the Azad Kashmir area, Pakistan

Abstract

Extensive export quality reserves of granite, dolerite and marbles which are used for interior decorations as wall facing, paving floors, kitchen counter tops, etc., are available in Azad Kashmir. Since these stones contain radium in trace amounts, therefore, its use as a building material may be a potential source of indoor radon. In order to assess health hazards due to the use of these stones as a building material, samples were collected from different mining sites. After processing, these samples were placed in plastic containers and box type radon detectors were installed in it at the height of 25 cm above the surface of the samples. The containers were then hermetically sealed. After 60 days of exposure to radon, CR-39 detectors were etched in 6 M NaOH at 70°C for 9 h and measured track densities were related to radon concentration. Radon exhalation rate form the studied granites, marble and dolerite samples varied from 87 ± 26 to 353 ± 36 mBq m -2 h -1 , 79 ± 25 to 650 ± 42 mBq m -2 h -1 and 90 ± 26 to 324 ± 36 mBq m -2 h -1 , respectively. These decorative stones are therefore used in buildings and for export purposes as the observed radon exhalation values are smaller than that of the EPA recommended-action level.

A review of radon measurement studies with nuclear track detectors (NTDs) in Azad Kashmir

“…These findings are comparable to the radon exhalation rate values reported by Rehman et al. 37,38 but noticeably smaller as compared to UNSCEAR (2000) reported values.…”

“…Measured values of radon exhalation rate from building materials' samples (soil, sand, aggregates and bricks) varied from 193 AE 11 to 308 AE 14 mBq m À2 h À1 , 366 AE 8 to 649 AE 8 mBq m À2 h À1 , 168 AE 17 to 322 AE 11mBq m À2 h À1 , 184 AE 14 to 231 AE 14 mBq m À2 h À1 , respectively. These findings are comparable to the radon exhalation rate values reported by Rehman et al37,38 but noticeably smaller as compared to UNSCEAR (2000) reported values.Radon exhalation rate from decorative stones, available in Azad Kashmir, were studied by Rafique et al37 Radon exhalation rate from the studied granites, marble and dolerite samples varied from 87 AE 26 to 353 AE 36 mBq m À2 h À1 , 79AE 25 to 650 AE 42 mBq m À2 h À1 and 90 AE 26 to 324 AE 36 mBq m À2 h À1 , respectively.Rafique et al38 investigated seasonal variations of indoor radon concentrations in four districts of Azad Kashmir, viz., Muzaffarabad, Hattian, Neelum and Poonch. Their findings show elevated values of radon in winter, while lower values were observed in summer season.…”

“…Radon exhalation rate from decorative stones, available in Azad Kashmir, were studied by Rafique et al. 37 Radon exhalation rate from the studied granites, marble and dolerite samples varied from 87 ± 26 to 353 ± 36 mBq m −2 h −1 , 79 ± 25 to 650 ± 42 mBq m −2 h −1 and 90 ± 26 to 324 ± 36 mBq m −2 h −1 , respectively.…”

Geological Materials as Sources of Rn Emissions

“…One can also highlight the results of Rafique & Rathore [11] which showed a significant value for a marble, being located in the central region of the histogram of log values and higher than many values for granites.…”

“…The consulted publications presented results of mass exhalation rates or surface exhalation rates or both (few publications) from diverse types of rocks. Granites are the rock type most frequently considered (Allen et al [3]; Chauhan [4]; Marocchi et al [5]; Moura et al [6]; Pereira et al [7,8]; Bavarnegin et al [9]; Pereira et al [10]; Rafique & Rathore [11]; Guillén et al [12]; Marques et al [13]; Andrade et al [14]), but there are also studies that include other igneous rocks (Chauhan [4]; Marocchi et al [5]; Moura et al [6]; Pereira Gómez et al [7]; Rafique & Rathore [11]; Guillén et al [12]), with a predominance of pyroclastic rocks (studied in Marocchi et al [5] ]; Andrade et al [14]; Turhan et al [15]; Kayakökü et al [16]. There are some studies with results on metamorphic rocks such as marbles (Bavarnegin et al [9]; Rafique & Rathore [11]; Andrade et al [14]) and silicate metamorphic rocks (Chauhan [4]; Marocchi et al [5]; Pereira et al [10]; Andrade et al [14]), and also some studies that include information in sedimentary rocks being (Bavarnegin et al [9]; Pereira et al [10]; Andrade et al [14]).…”