| Summary: | The indoor Radon-222 concentration and emanation rate in Gua Penyu, Gua Gelanggi Complex, Pahang were measured using Solid State Nuclear Track Detector CR-39 (SSNTD CR-39) to evaluate the air quality and radiological exposure in this recreational cave. A total of 20 SSNTD CR-39 dosimeters were placed inside the cave at about 15 m apart each. 10 dosimeters were embedded 5 cm into cave floor to determine emanation rate, while the other 10 dosimeters were placed at one meter above the floor level for concentration measurement. The control samples were placed outside the cave 15 m from the main entrance. These SSNTD CR-39 samples were left for a month before undergone etching process with NaOH solution (6 M) at 70 °C for six hours. The radon concentration and emanation rate were both determined from the track density in each CR-39 (1cm ☓ 1cm) sampling. The results showed that the radon emanation rates varied between 0.030 ±0.004 Bqm-2day-1 and 0.120 ± 0.017 Bqm-2day-1 with the average rate of 0.080 Bqm-2day-1. The radon concentration was between 3.72 ± 1.60 Bqm-3 and 7.89 ± 2.10 Bqm-3 with the average of 4.8 Bqm-3. These values were lower compared to indoor concentration allowed by the International Commission on Radiation Protection (ICRP) 2009 that is 200 – 300 Bqm-3. The annual effective dose were found to range between 0.09 mSv.y-1 and 0.20 mSv.y-1 which was lower than recommended value 3 to 10 mSv.y-1 put forth by the ICRP 1993. Hence, this recreational cave is safe to be visited by public. © 2018, Malaysian Society of Analytical Sciences. All rights reserved.
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