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Public exposure to radon and thoron progeny in Romania
International Congress Series 1276 (2005) 373 – 374
www.ics-elsevier.com
Public exposure to radon and thoron progeny in Romania Olga Iacob*, Constantin Grecea Radiation Hygiene Laboratory, Institute of Public Health, 14,Victor Babes Street, Iassy 700465, Romania
Abstract. The purpose of our work was to determine the activity concentrations of short-lived decay products of radon and thoron in dwellings and in free air and to evaluate, in terms of effective doses, the magnitude of the resulting annual exposure of population in eastern Romania. The activity concentrations of 218Po, 214Pb, 214Bi and 212Pb have been measured in 684 typical urban and rural houses. The average values of EEC of radon were 28 Bq m 3 in detached houses and 9 Bq m 3 in block of flats, with individual values ranging from 3.8 to 564 Bq m 3. The average values of EEC of thoron were of 1.3 Bq m 3 in detached houses and 0.6 Bq m 3 in block of flats, with individual values ranging from 0.1 to 12.8 Bq m 3. Outdoor average values of EEC were 4.6 Bq m 3 for radon progeny and 0.2 Bq m 3 for thoron progeny. The overall annual effective dose per capita was 2.0 mSv (1.65 mSv from radon progeny and 0.35 mSv from thoron progeny) with a corresponding annual collective effective dose of 10,370 manSv. D 2004 Elsevier B.V. All rights reserved. Keywords: Population exposure; Radon and thoron progeny; Effective dose
1. Introduction The radiation dose from inhaled radon and thoron progeny indoors and outdoors is the dominant component of population exposure to natural radiation sources accounting for about 60% in Romania [1]. The purpose of our work was to determine the activity concentrations of short-lived decay products of radon and thoron, indoors and outdoors, and to evaluate the magnitude of the resulting annual exposure of the Romanian population. 2. Materials and methods 214
The measurements of the radon and thoron short-lived decay products (218Po, 214Pb, Bi and 212Pb) concentrations have been carried out in 684 typical urban and rural houses, * Corresponding author. Tel.: +40 232 410399; fax: +40 232 210399. E-mail address: olga [email protected] (O. Iacob).
0531-5131/ D 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.ics.2004.11.019
374
O. Iacob, C. Grecea / International Congress Series 1276 (2005) 373–374
Table 1 Indoor and outdoor average concentrations of Radio nuclide
Location
222
Rn and
220
Rn progeny and the resulting annual effective doses
3
EEC (Bqd m )
Annual effective dose
Average
Range
Average
20.3 28 9 4.6
3.8–564 2.6–19.4 1.0–7.3
1.0 1.3 0.6 0.2
0.2–6.4 0.1–2.8 0.1–0.6
(mSv) 222
Rn progeny
220
Rn progeny
INDOORS Detached house Block of flats OUTDOORS Total 222Rn INDOORS Detached house Block of flats OUTDOORS Total 222Rn
Total
1.20 1.66 0.51 0.09 1.29 0.26 0.34 0.16 0.02 0.28 1.57
(manSv) Range 0.23–33.3 0.20–1.15 0.02–0.14
0.05–0.74 0.03–0.74 0.01–0.05
Per capita
Collective
1.53
7930
0.12 1.65 0.33
593 8523 1737
0.02 0.35 2.0
109 1846 10,370
randomly selected from 8 cities and 136 villages. The method used was the active one of sucking a known volume of air through a high-efficiency filter paper and counting the deposited activity using an alpha scintillation counter [2]. Internal exposure due to inhalation of 222Rn and 220Rn daughters in indoor and outdoor air, expressed in terms of effective dose, was estimated by using the dose conversion coefficients adopted in the UNSCEAR 2000 Report [3]. An indoor occupancy factor of 0.75 and a population size of 5.2 million inhabitants (27% children and 73% adults) have been considered in all calculations. 3. Results and discussion The results of our study are included in Table 1. The average value for EEC of radon was 28 Bq m 3 in houses and 9 Bq m 3 in flats and the average value for EEC of thoron was 1.3 Bq m 3 in houses and 0.6 Bq m 3 in flats. The indoor population-weighted averages of the EECs of radon and thoron were estimated at 20.3 and 1.0 Bq m 3. The average annual effective dose to adult was 1.20 mSv from indoor inhaled radon progeny, individual values ranging between 0.20 and 33.3 mSv. The average annual effective dose to adult due to indoor inhaled thoron progeny was 0.26 mSv, with individual values ranging between 0.03 and 1.68 mSv. The overall annual effective dose per capita, in assumption that dose received by a child is twice the adult dose, was estimated at 2.0 mSv–1.65 mSv from radon progeny and 0.35 mSv from thoron progeny—with a corresponding annual collective effective dose of 10,370 manSv. 4. Conclusions The annual effective dose per capita resulting from the radon isotopes inhalation, indoors and outdoors, was estimated at 2 mSv of which 77% is due to indoor 222Rn progeny. The corresponding annual collective effective dose was calculated to be 10,370 manSv. References [1] O. Iacob, E. Botezatu, Population exposure to natural radiation sources in Romania, Proc. of the 11th IRPA Congress, 23–28 May 2004 Madrid, Spain, 2004, http://www.irpa11.com/new/pdfs/6a33.pdf. [2] Romanian Institute of Standardization, Air quality: volumetric activity determination of 218Po, 218Pb, 214Bi and 218Pb. Romanian Standard SR-13397, 1997. [3] United Nations Scientific Committee on Effects of Atomic Radiation, Report 2000, UN, New York, 2000.
www.ics-elsevier.com
Public exposure to radon and thoron progeny in Romania Olga Iacob*, Constantin Grecea Radiation Hygiene Laboratory, Institute of Public Health, 14,Victor Babes Street, Iassy 700465, Romania
Abstract. The purpose of our work was to determine the activity concentrations of short-lived decay products of radon and thoron in dwellings and in free air and to evaluate, in terms of effective doses, the magnitude of the resulting annual exposure of population in eastern Romania. The activity concentrations of 218Po, 214Pb, 214Bi and 212Pb have been measured in 684 typical urban and rural houses. The average values of EEC of radon were 28 Bq m 3 in detached houses and 9 Bq m 3 in block of flats, with individual values ranging from 3.8 to 564 Bq m 3. The average values of EEC of thoron were of 1.3 Bq m 3 in detached houses and 0.6 Bq m 3 in block of flats, with individual values ranging from 0.1 to 12.8 Bq m 3. Outdoor average values of EEC were 4.6 Bq m 3 for radon progeny and 0.2 Bq m 3 for thoron progeny. The overall annual effective dose per capita was 2.0 mSv (1.65 mSv from radon progeny and 0.35 mSv from thoron progeny) with a corresponding annual collective effective dose of 10,370 manSv. D 2004 Elsevier B.V. All rights reserved. Keywords: Population exposure; Radon and thoron progeny; Effective dose
1. Introduction The radiation dose from inhaled radon and thoron progeny indoors and outdoors is the dominant component of population exposure to natural radiation sources accounting for about 60% in Romania [1]. The purpose of our work was to determine the activity concentrations of short-lived decay products of radon and thoron, indoors and outdoors, and to evaluate the magnitude of the resulting annual exposure of the Romanian population. 2. Materials and methods 214
The measurements of the radon and thoron short-lived decay products (218Po, 214Pb, Bi and 212Pb) concentrations have been carried out in 684 typical urban and rural houses, * Corresponding author. Tel.: +40 232 410399; fax: +40 232 210399. E-mail address: olga [email protected] (O. Iacob).
0531-5131/ D 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.ics.2004.11.019
374
O. Iacob, C. Grecea / International Congress Series 1276 (2005) 373–374
Table 1 Indoor and outdoor average concentrations of Radio nuclide
Location
222
Rn and
220
Rn progeny and the resulting annual effective doses
3
EEC (Bqd m )
Annual effective dose
Average
Range
Average
20.3 28 9 4.6
3.8–564 2.6–19.4 1.0–7.3
1.0 1.3 0.6 0.2
0.2–6.4 0.1–2.8 0.1–0.6
(mSv) 222
Rn progeny
220
Rn progeny
INDOORS Detached house Block of flats OUTDOORS Total 222Rn INDOORS Detached house Block of flats OUTDOORS Total 222Rn
Total
1.20 1.66 0.51 0.09 1.29 0.26 0.34 0.16 0.02 0.28 1.57
(manSv) Range 0.23–33.3 0.20–1.15 0.02–0.14
0.05–0.74 0.03–0.74 0.01–0.05
Per capita
Collective
1.53
7930
0.12 1.65 0.33
593 8523 1737
0.02 0.35 2.0
109 1846 10,370
randomly selected from 8 cities and 136 villages. The method used was the active one of sucking a known volume of air through a high-efficiency filter paper and counting the deposited activity using an alpha scintillation counter [2]. Internal exposure due to inhalation of 222Rn and 220Rn daughters in indoor and outdoor air, expressed in terms of effective dose, was estimated by using the dose conversion coefficients adopted in the UNSCEAR 2000 Report [3]. An indoor occupancy factor of 0.75 and a population size of 5.2 million inhabitants (27% children and 73% adults) have been considered in all calculations. 3. Results and discussion The results of our study are included in Table 1. The average value for EEC of radon was 28 Bq m 3 in houses and 9 Bq m 3 in flats and the average value for EEC of thoron was 1.3 Bq m 3 in houses and 0.6 Bq m 3 in flats. The indoor population-weighted averages of the EECs of radon and thoron were estimated at 20.3 and 1.0 Bq m 3. The average annual effective dose to adult was 1.20 mSv from indoor inhaled radon progeny, individual values ranging between 0.20 and 33.3 mSv. The average annual effective dose to adult due to indoor inhaled thoron progeny was 0.26 mSv, with individual values ranging between 0.03 and 1.68 mSv. The overall annual effective dose per capita, in assumption that dose received by a child is twice the adult dose, was estimated at 2.0 mSv–1.65 mSv from radon progeny and 0.35 mSv from thoron progeny—with a corresponding annual collective effective dose of 10,370 manSv. 4. Conclusions The annual effective dose per capita resulting from the radon isotopes inhalation, indoors and outdoors, was estimated at 2 mSv of which 77% is due to indoor 222Rn progeny. The corresponding annual collective effective dose was calculated to be 10,370 manSv. References [1] O. Iacob, E. Botezatu, Population exposure to natural radiation sources in Romania, Proc. of the 11th IRPA Congress, 23–28 May 2004 Madrid, Spain, 2004, http://www.irpa11.com/new/pdfs/6a33.pdf. [2] Romanian Institute of Standardization, Air quality: volumetric activity determination of 218Po, 218Pb, 214Bi and 218Pb. Romanian Standard SR-13397, 1997. [3] United Nations Scientific Committee on Effects of Atomic Radiation, Report 2000, UN, New York, 2000.