Atmospheric Environment 39 (2005) 7761 7767 www.elsevier.com/locate/atmosenv Seasonal variation of indoor radon in dwellings of Malwa region, Punjab Surinder Singh a,, Rohit Mehra b, Kulwant Singh a a Department of Physics, Guru Nanak Dev University, Amritsar, India b Department of Applied Sciences, Malout Institute of Management and Information Technology, Malout, India Received 15 April 2005; accepted 7 August 2005 Abstract Indoor radon measurements in 105 dwellings belonging to 21 villages of Muktsar and Ferozepur districts of Malwa region, Punjab, have been carried out, using LR-115 type II cellulose nitrate films in the bare mode. The annual average indoor radon value in the study area varies from 76.25 to 145.50 Bq m 3, which is well within the recommended action level [ICRP, 1993. Protection against radon at home and work. Annals of ICRP, ICRP Publication, p. 65]. Seasonal variation of indoor radon shows high values in winter and low values in. The winter/ of radon concentn has been computed for all 105 dwellings. The winter/ of indoor radon ranges from 0.84 to 1.89 with an average of 1.46. The indoor radon values obtained in the present investigation are more than the world average of 40 Bq m 3 r 2005 Elsevier Ltd. All rights reserved. Keywords: Radon; Thoron; Cancer; Dwellings; LR-115 1. Introduction Radon ( 222 Rn) a decay product of radium in the naturally occurring uranium series is a radioactive inert gas and is responsible for about half of the radiation dose received by the general population (UNSCEAR, 1994). Radon isotopes can isolate themselves and migrate away from the parent mineral due to diffusion process through the soil and enter the atmosphere. The radon and its progeny attached to aerosols present in the ambient air constitute significant radioactive hazards to human lungs. During respin radon progeny Corresponding author. Tel.: +91 183 225 7007; fax: +91 183 225 8820. E-mail address: surinder51@yahoo.com (S. Singh). deposits in the lungs and irradiate the tissue thereby damaging the cells and may cause lung cancer. Henshaw et al. (1990) claimed that indoor radon exposure is associated with the risk of leukemia and certain other cancers, such as melanoma and cancers of the kidney and prostate.the concentn of radon and its decay products show large temporal and local fluctuations in the indoor atmosphere due to the variations of temperature, pressure, nature of building materials, ventilation s and wind speed, etc. In the study area 21 villages and five houses in each village were chosen for indoor radon studies. The houses were chosen in such a way that the dwellings constructed with different types of building materials and in different localities of the village are covered. The surveyed area (Fig. 1) is bounded on the western side by 1352-2310/$ - see front matter r 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.atmosenv.2005.08.030
7762 S. Singh et al. / Atmospheric Environment 39 (2005) 7761 7767 Fig. 1. Map of Punjab showing Muktsar and Ferozepur area surveyed during the present investigations. Pakistan; on the south by Rajasthan and Haryana. The latitude and longitude of Muktsar and Ferozepur districts are 30.301N, 74.431E and 30.551N, 74.401E, respectively. Most of the area is affected by the water-logging problem. For health risk assessment, radon measurements were carried out for a period of one year. The annual exposure to occupants, the annual effective dose received by them and their lifetime fatality risk estimates have been assessed in the light of guidelines given by International Commission on Radiological Protection (ICRP, 1993). 2. Experimental methods Several methods are in use for measurement of radon and its daughter elements in dwellings. Some measuring the short-term values are called active methods and others measuring the integrated values are called passive methods. LR-115 type II plastic track detector films and the bare mode technique (Mishra and Ramachandran, 1997; Ramola et al., 1998; Singh et al., 2001) have been employed to measure the concentn of radon in the indoor environment. The detectors of size 1.3 cm 1.5 cm were suspended in the rooms on quarterly basis at a height more than 2 m above the level of the ground (so that the detectors are not disturbed by the movement of the residents) and about 1 m below the ceiling of the room so that direct alpha particles from the building material of the ceiling do not reach the detectors. We have assumed that a room with a door and without window is poorly ventilated, that with one window and a door as partially ventilated and with more than two windows and a door as well ventilated. All the detectors were removed and
S. Singh et al. / Atmospheric Environment 39 (2005) 7761 7767 7763 Table 1 Indoor radon levels in the dwellings of Muktsar and Ferozepur Districts of Punjab Sr. no. Sample location (village) No. of dwellings studied (Bq m 3 ) in winter (Dec Feb) (Bq m 3 ) in spring (Mar May) (Bq m 3 ) in (June Aug) (Bq m 3 ) in autumn (Sep-Nov) Annual averageradon concentn (Bq m 3 ) Life-time fatality risk X10 4 Annual average dose (msv) Muktsar district 1 Abul Khurana 5 170 154 16075.84 116 95 10779.52 139 109 121711.1 103 87 9476.87 120.50 1.59 2.06 2 Deon Khera 5 112 96 10378.02 81 68 7775.24 76 54 6178.79 91 79 8474.82 81.25 1.07 1.39 3 Phoolu Khera 5 228 223 22672.23 104 87 9476.80 137 118 12978.54 117 101 10975.83 139.50 1.84 2.38 4 Kabarwala 5 128 116 12475.45 75 58 6776.59 94 78 8775.80 125 117 12173.19 99.75 1.32 1.70 5 Pakki 5 181 150 170713.73 109 99 10374.02 123 110 11875.17 132 104 117712.15 127.00 1.68 2.17 6 Giddarbaha 5 131 116 12275.85 97 92 9471.92 94 87 9272.92 104 79 89710.93 99.25 1.31 1.69 7 Badal 5 151 112 138715.04 75 64 7274.53 97 79 9076.78 97 69 84711.21 96.00 1.27 1.64 8 Jandwala 5 143 112 13278.79 86 70 7776.22 109 92 10176.67 113 98 10775.72 104.25 1.38 1.78 9 Jurar 5 100 85 9578.91 62 51 5774.97 71 54 6376.59 102 87 9375.79 77.00 1.02 1.31 10 Malout 5 120 96 112710.91 75 63 6974.82 89 71 7877.52 98 79 9177.79 87.50 1.16 1.49 11 Virk Khera 5 135 127 13374.46 81 62 7176.98 117 89 97711.51 111 87 9479.78 98.75 1.30 1.69 12 Muktsar 5 118 96 11271.41 98 80 8977.92 81 69 7275.10 89 73 8276.42 88.75 1.17 1.52 13 Sarawan 5 143 120 13478.79 113 92 10279.18 103 87 9476.61 91 74 8477.12 103.50 1.37 1.77 Ferozepur district 14 Dangar Khera 5 154 142 15275.85 86 73 7974.97 111 89 102710.25 104 92 9774.82 107.50 1.42 1.84 15 Abohar 5 124 115 12072.72 79 56 7279.76 98 78 8378.43 87 63 80710.03 88.75 1.17 1.52 16 Khubban 5 190 143 161724.8 103 74 92711.78 128 112 12176.40 111 71 91717.31 116.25 1.53 1.98 17 Radhewala Chak 5 240 228 23375.87 111 79 98714.21 151 129 13878.93 140 98 123719.21 145.50 1.92 2.48 18 Himmatpura 5 181 166 174710.91 117 95 10779.48 122 102 11377.81 153 103 134721.64 132.00 1.74 2.25 19 Sitoguno 5 108 58 75722.82 78 70 7373.39 94 69 80710.42 83 70 7775.26 76.25 1.01 1.30 20 Balluana 5 131 120 12575.89 85 57 79712.20 99 69 85712.94 106 95 10274.53 97.75 1.29 1.67 21 Ferozepur 5 135 116 130712.14 79 65 7175.12 90 74 7976.32 99 83 9176.26 92.75 1.22 1.58
7764 S. Singh et al. / Atmospheric Environment 39 (2005) 7761 7767 Table 2 Indoor radon concentns (Bq m 3 ) during winter and for dwellings belonging to different areas of Muktsar and Ferozepur districts of Malwa region Sr. no. Sample location s dwelling 1 s dwelling 2 s dwelling 3 s dwelling 4 s dwelling 5 1 Abul Khurana Well ventilated 170 139 1.22 Partially ventilated 154 109 1.41 Well ventilated 158 118 1.34 Well ventilated 158 117 1.35 Well ventilated 158 121 1.31 2 Deon Khera Poorly ventilated 112 76 1.47 Poorly ventilated 96 54 1.78 Poorly ventilated 101 58 1.74 Poorly ventilated 103 56 1.84 Partially ventilated 100 62 1.61 3 Phoolu Khera Poorly ventilated 228 137 1.66 Poorly ventilated 223 118 1.89 Poorly ventilated 226 122 1.85 Poorly ventilated 228 132 1.73 Poorly ventilated 226 136 1.66 4 Kabarwala Partially ventilated 128 94 1.36 Partially ventilated 116 78 1.49 Well ventilated 123 88 1.4 Partially ventilated 127 89 1.43 Well ventilated 123 87 1.41 5 Pakki Partially ventilated 181 123 1.47 Well Ventilated 150 110 1.36 Partially ventilated 169 119 1.42 Well ventilated 177 117 1.51 Poorly ventilated 170 122 1.39 6 Giddarbaha Partially ventilated 131 94 1.39 Well ventilated 116 87 1.33 Well ventilated 120 92 1.3 Well ventilated 120 93 1.29 Partially ventilated 123 94 1.31 7 Badal Poorly ventilated 151 97 1.56 Partially ventilated 112 79 1.42 Partially ventilated 143 89 1.61 Partially ventilated 143 92 1.55 Partially ventilated 143 93 1.54 8 Jandwala Partially ventilated 143 109 1.31 Well ventilated 112 92 1.22 Well ventilated 135 102 1.32 Well ventilated 135 97 1.39 Well ventilated 135 105 1.29 9 Jurar Partially ventilated 100 71 1.41 Partially ventilated 85 54 1.57 Partially ventilated 94 59 1.59 Well ventilated 96 66 1.45 Poorly ventilated 100 65 1.54 10 Malout Partially ventilated 120 89 1.35 Well ventilated 96 71 1.35 Partially ventilated 120 76 1.58 Well ventilated 112 82 1.37 Poorly ventilated 112 72 1.56 11 Virk Khera Well ventilated 135 117 1.15 Partially ventilated 127 89 1.43 Well ventilated 135 96 1.41 Partially ventilated 131 93 1.41 Well ventilated 133 90 1.48 12 Muktsar Poorly ventilated 118 81 1.46 Well ventilated 96 69 1.39 Partially ventilated 116 70 1.66 Partially ventilated 120 69 1.74 Well ventilated 112 71 1.58 13 Sarawan Well ventilated 143 103 1.39 Partially ventilated 120 87 1.38 Partially ventilated 135 90 1.5 Well ventilated 135 99 1.36 Partially ventilated 139 92 1.51 14 Dangar Khera Partially ventilated 154 111 1.39 Poorly ventilated 142 89 1.6 Well ventilated 154 107 1.44 Poorly ventilated 154 93 1.66 Partially ventilated 154 110 1.4 15 Abohar Well ventilated 124 98 1.27 Well ventilated 115 78 1.47 Partially ventilated 120 80 1.5 Partially ventilated 121 80 1.51 Partially ventilated 120 79 1.52 16 Khubban Poorly ventilated 190 128 1.48 Well ventilated 143 112 1.28 Well ventilated 150 124 1.21 Well ventilated 160 117 1.37 Well ventilated 162 124 1.31 17 Radhewala Chak Poorly ventilated 240 151 1.59 Poorly ventilated 228 129 1.77 Partially ventilated 231 142 1.63 Poorly ventilated 233 136 1.71 Poorly ventilated 231 131 1.76 18 Himmatpura Poorly ventilated 181 122 1.48 Poorly ventilated 166 102 1.63 Well ventilated 171 109 1.57 Well ventilated 172 118 1.46 Partially ventilated 173 114 1.52 19 Sitoguno Well ventilated 108 94 1.15 Well ventilated 58 69 0.84 Well ventilated 75 78 0.96 Well ventilated 63 72 0.88 Well ventilated 73 87 0.84 20 Balluana Partially ventilated 131 99 1.32 Partially ventilated 120 69 1.74 Poorly ventilated 123 74 1.66 Well ventilated 123 89 1.38 Partially ventilated 125 94 1.33 21 Ferozepur Partially ventilated 135 90 1.5 Partially ventilated 116 74 1.57 Poorly ventilated 130 76 1.71 Poorly ventilated 135 78 1.73 Poorly ventilated 134 77 1.74
S. Singh et al. / Atmospheric Environment 39 (2005) 7761 7767 7765 etched using 2.5N NaOH solution at 60 1C for 90 min. The track density was counted using an optical microscope at a magnification of 400 and was converted using a calibn constant 0.02 tracks cm 2 day 1 ¼ 1Bqm 3 (Eappen et al., 2001). 3. Results and discussions The indoor radon concentn levels recorded in 21 villages of Muktsar and Ferozepur districts are given in Table 1. The annual effective dose and average lifetime fatality risk for each of the 21 villages have also been calculated. The calculations have been made using the conversion factors given elsewhere (ICRP, 1993; Raghavayya, 1994). ICRP assumes 80% occupancy (7000 h/yr) indoor and an F (equilibrium factor) value of 0.4 for dwellings. One working level month (WLM) corresponds to the exposure of an individual to radon progeny of 1 WL concentn (2.08 10 2 mj m 3 ) for a dun of 170 h, which results 1 WLM equivalent to 3.54 mj h m 3. The conversion factors of 3 10 4 WLM 1 and 3.88 msv WLM 1 (ICRP, 1993) are used for calculating the lifetime fatality risk and the annual effective dose, respectively. The annual average indoor radon value in the study area varies from 76.25 (Sitoguno village) to 145.50 Bq m 3 (Radhewala chak village). These values are two to three times more than the world average of 40 Bq m 3 (UNSCEAR, 2000). This may be due to the difference in the concentn of radioactive elements viz. uranium and radium in the soil and building materials of the study area. However, these values are less than the lower limit of the range of the action level (200 600 Bq m 3 ), recommended by the International Commission on Radiological Protection (ICRP, 1993). The present values of indoor radon are slightly more than those in some other areas of Punjab reported by Sharma and Virk (1998) but are lower than those reported for Himachal Pradesh by Singh et al. (1998, 2001). Comparatively high values of indoor radon in some areas of Himachal Himalayas may be due to the presence of uranium mineralization reported by Kaul 180 160 Annual Average Radon Concentn (Bq m -3 ) 140 120 100 80 60 40 20 0 1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77 81 85 89 93 97 101 105 Dwellings Fig. 2. Distribution of annual average radon concentn (Bq m 3 ) in 105 dwellings of 21 villages of Muktsar and Ferozepur districts of Punjab, India.
7766 S. Singh et al. / Atmospheric Environment 39 (2005) 7761 7767 et al. (1993). The annual effective dose received by the residents of the study area varies from 1.3 to 2.48 msv with an average of 1.77 msv. In all the villages surveyed, the annual effective dose is less than even the lower limit of the recommended action level (3 10 msv). The lifetime fatality risk of the residents of the study area varies from 1.01 10 4 to 1.92 10 4 with an average value of 1.37 10 4. The average value of the lifetime fatality risk of 1.37 10 4 (0.01%) is relatively a small fraction (about 4%) of the lifetime risk of lung cancer due to cigarette smoking and chewing of tobacco (Evans et al., 1981). The seasonal variations of indoor radon concentn in 105 dwellings of 21 villages are given in Table 2. It is evident from the table that the maximum value of radon concentn is observed during the winter season and minimum during the season. This is because the doors and windows of the dwellings remain closed most of the times in winter compared with and hence the ventilation is poor in winter. The winter/ of radon concentn has been computed for all 105 dwellings. The winter/ of indoor radon ranges from 0.84 to 1.89 with an average of 1.46. Moreover, the results (Table 2) reveal that in general the indoor radon values are more in the poorly ventilated houses compared with the well-ventilated ones. Our results for seasonal variations show a behaviour which agrees with the findings of Mittal et al. (1998) for the dwellings of Rajasthan area and that of Singh et al. (2002) for Himachal Pradesh. Fig. 2 shows the distribution of the annual average radon concentn for all the 105 dwellings of 21 villages studied in Muktsar and Ferozepur districts. The annual radon concentn level for dwellings ranges from 66.75 to 160.50 Bq m 3, with an average of 103.81 Bq m 3. The difference in the values of indoor radon activity may be due to the different ventilation s, the nature and type of building materials used during construction and the variation of the radioactivity level in the soil beneath the dwellings. Fig. 3 shows the frequency distribution of the annual average radon concentn levels among 105 dwellings of 21 villages of the study area. The radon concentn lies in the ranges 50 100, 100 150 and 150 200 Bq m 3 in about 51%, 46% and 3% of the houses, respectively. In almost all the dwellings radon concentn is well below the recommended level. 4. Conclusions 1. In general the radon concentn values in the dwellings are two to three times more than the world average of 40 Bq m 3. However, these values are lower than the recommended action level. 60 54 50 48 Number of dwellings 40 30 20 10 0 3 0 0-50 50-100 100-150 150-200 Annual Average Radon Concentn (Bq m -3 ) Fig. 3. Frequency distribution of annual average radon concentn (Bq m 3 ) in 105 dwellings of 21 villages of Muktsar and Ferozepur districts of Punjab, India.
S. Singh et al. / Atmospheric Environment 39 (2005) 7761 7767 7767 2. Maximum value of radon concentn is observed during the winter and minimum during the season. 3. The annual effective dose in the study area is less than even the lower limit of the recommended action level (3 10 msv). Acknowledegments The authors are thankful to the residents of the study area for their co-open during the fieldwork, and to the students and staff of MIMIT, Malout, and Laboratory staff of Guru Nanak Dev University, Amritsar, India, for their support. References Eappen, K.P., Ramachandran, T.V., Shaikh, A.N., Mayya, Y.S., 2001. Calibn factor for SSNTD-based radon/thoron dosimeters. Radiation Protection and Environment 24 (1 2), 410 414. Evans, R.D., Harley, J.H., Jacobi, W., MacLean, A.S., Mills, W.A., Stewart, C.G., 1981. Estimation of risk from environmental exposure to radon-222 and its decay products. Nature 290, 98 100. Henshaw, D.L., Eatough, J.P., Richardson, R.B., 1990. Radon as a causative factor in induction of myeloid leukemia and other cancers. Lancet 355, 1008 1015. ICRP, 1993. Protection against Radon at Home and Work. Ann ICRP. ICRP Pub., p. 65. Kaul, R., Umamaheshwar, K., Chandrashekaran, S., Deshmukh, R.D., Swarmukar, B.M., 1993. Uranium mineralization in the Siwaliks of Northwestern Himalayan, India. Journal 0f Geological Soceity of India 41, 243 258. Mishra, U.C., Ramachandran, T.V., 1997. Indoor radon levels in India: a review. In: Proceedings Third International Conference on Rare Gas Geo-Chemistry, Amritsar. Guru Nanak Dev University Press, Amritsar, India, pp. 310 319. Mittal, S., Bhatti, S.S., Jodha, A.S., Kumar, S., Ramachandran, T.V., Nambi, K.S.V., 1998. A correlation study between radon in dwellings and radium concentn in soil. In: Proceedings of XIth National Symposium, SSNTD, 12 14 October. Amritsar, pp. 268 274. Raghavayya, M., 1994. Safety standards for exposure to radon. Bulletin on Radiation Protection 17 (3 4), 1 4. Ramola, R.C., Kandari, M.S., Rawat, R.B.S., Ramachandran, T.V., Choubey, V.M., 1998. A study of seasonal variation of radon levels in different types of houses. Journal Of Environmental Radioactivity 39 (1), 1 7. Sharma, N., Virk, H.S., 1998. Indoor levels of radon/thoron daughters in some dwellings of Punjab. In: Proceedings of XIth National Symposium, SSNTD, 12 14 October. Amritsar, pp. 259 262. Singh, S., Singh, B., Kumar, J., 1998. Uranium and radon measurement in the environs of Himachal Himalayas, an application of solid state nuclear track detectors. In: Proceedings of the XIth National Symposium, SSNTD, 12 14 October. Amritsar, pp. 69 78. Singh, S., Malhotra, R., Kumar, J., Singh, L., 2001. Indoor radon measurements in dwellings of Kulu area, Himachal Pradesh, using solid state nuclear track detectors. Radiation Measurements 34, 505 508. Singh, S., Kumar, A., Singh, B., 2002. Radon level in dwellings and its correlation with uranium and radium content in some areas of Himachal Pradesh, India. Environmental International 28, 97 101. UNSCEAR, 1994. United Nations Scientific Committee on the Effects of Atomic Radiation. Ionizing Radiation: Sources and Biological Effects. United Nations, New York. UNSCEAR, 2000. United Nations Scientific Committee on the Effects of Atomic Radiation. Ionizing Radiation: Exposure due to Natural Radiation Sources. United Nations, New York.