nan Matiullah

Measurement of natural radioactivity in Jordanian sand

Abstract Sand samples were collected from Adasiah (near Amman), Jerash and Ghor As-Safi (near Karak). 226 Ra, 232 Th and 40 K activities, present in these samples, were measured using a gamma ray spectroscopy technique. The average values of the radium equivalent activities were calculated and were found to be 41.06 Bq kg −1 , 54.7 Bq kg −1 and 85.53 Bq kg −1 in samples collected from Adasiah, Jerash and Ghor As-Safi, respectively. These values are within the limit (i.e. less than 370 Bq kg −1 ) recommended for the safe use of construction materials for dwellingsby OECD.

Indoor radon concentration measurement in the dwellings of district Poonch (Azad Kashmir), Pakistan

The present study deals with measurement of indoor radon concentrations in dwellings of the district Poonch of the state of Azad Jammu and Kashmir, Pakistan. In this context, CR-39-based box-type radon detectors were installed in drawing rooms and bedrooms of 80 selected houses and were exposed to indoor radon for 3 months. After exposure, the CR-39 detectors were etched for 9 h in 6 mol NaOH at 70 degrees C and the observed track densities were related to radon concentrations. Measured indoor radon concentrations in the studied area ranged from 27 +/- 6 to 169 +/- 4, 29 +/- 6 to 196 +/- 4 and 31 +/- 5 to 142 +/- 2 Bq m(-3) in the drawing rooms and 74 +/- 5 to 172 +/- 3, 32 +/- 6 to 191 +/- 4 and 27 +/- 5 to 155 +/- 2 Bq m(-3) in bedrooms of the Abbaspur, Hajira and Rawalakot regions of the district Poonch, respectively; whereas weighted average radon concentration ranged from 93 +/- 6 to 159 +/- 4, 33 +/- 5 to 118 +/- 3 and 31 +/- 6 to 155 +/- 5 Bq m(-3) in the dwellings of Abbaspur, Hajira and Rawalakot, respectively. Estimated doses due to the indoor radon ranged from 2.35 +/- 0.15 to 4.00 +/- 0.10, 0.83 +/- 0.08 to 2.98 +/- 0.08 and 0.78 +/- 0.15 to 3.91 +/- 0.13 mSv y(-1) for Abbaspur, Rawalakot and Hajira, respectively. Comparing the current indoor radon results with those of the Health Protection Agency UK and US EPA (i.e. 200 and 148 Bq m(-3)) limits, majority of the houses surveyed in the present study are within the safe limits.

Assessment of indoor radon doses received by the students in the Azad Kashmir schools, Pakistan.

Several epidemiological studies conducted on thousands of underground miners suggest that long- term exposure to high radon concentration can increase the risk of lung cancer. Keeping in view the importance of the subject, numerous studies throughout the world have been carried out to measure indoor radon concentration and its resulting doses at occupational and non-occupational sites. The purpose of the current study was to measure indoor radon concentration and its resulting doses received by the students of Azad Kashmir government schools. For this purpose, CR-39 radon detectors were installed in 80 carefully selected schools. The detectors were placed at a height of 3-5 ft. (depending upon average height of students in particular class) from the ground. After exposure of 90 d detectors were etched for 9 h in 6 M NaOH at 70°C and the observed track densities were related to radon concentrations. The measured indoor radon concentration ranged from 22 ± 9 to 228 ± 3 Bq m(-3) with a mean value of 78 ± 5 Bq m(-3). Based on the measured indoor radon data, the annual effective doses were found to vary from 0.55 ± 0.04 to 0.71 ± 0.03 mSv y(-1). The overall mean effective dose for the studied area was found to be 0.63 ± 0.04 mSv y(-1). Reported values for radon concentrations and corresponding doses are lower than ICRP recommended limits for workplaces.

Preliminary radon concentration-survey in some houses of Islamabad

Abstract Measurements of radon and its daughter products have been carried out in 13 houses in the city of Islamabad (Pakistan). Both CR-39 and CN-85 detectors were installed in bed rooms, kitchens and drawing rooms of the chosen houses and were exposed to radon and its daughters over a period of about four months. All the exposed detectors were processed employing the optimized etching conditions. Significant variation in radon concentration has been observed in the houses under investigation.

Seasonal variation in indoor radon concentrations in dwellings in six districts of the Punjab province, Pakistan

An indoor radon measurement survey has been carried out in six districts of the Punjab province. These included Gujranwala, Gujrat, Hafizabad, Sialkot, Narowal and Mandibahauddin districts. In each district, 40 representative houses were chosen and indoor radon levels were measured in these dwellings in autumn, winter, spring and summer seasons using CR-39 based NRPB radon dosimeters. After exposure to radon, the CR-39 detectors were etched in 25% NaOH at 80 degrees C and track densities were related to radon concentration levels. From the observed data, average radon concentration levels and a seasonal correction factor were calculated. The average 222Rn concentration level was found to vary from 40 +/- 15 to 160 +/- 32 Bq m(-3) and 38 +/- 17 to 141 +/- 26 Bq m(-3) in the bedrooms and living rooms of the houses surveyed, respectively. The annual mean effective dose received by the occupants has been calculated using ICRP (1993 Ann. ICRP 23) and UNSCEAR (2000 Sources and Effects of Ionizing Radiation (New York: United Nations)); it varied from 1.2 to 1.7 mSv and from 1.8 to 2.4 mSv, respectively.

Environmental radioactivity in Dera Ismail Khan and its adjacent area - Pakistan

Abstract Natural radioactivity in air, soil and water samples has been determined in Dera Ismail (D.I.) Khan city and its adjacent areas in Pakistan. CR-39 detectors were used for investigating radon concentration in the air of different kinds of rooms. HPGe detectors were employed for gamma ray activity measurements in the soil used normally to produce the construction materials. 235U concentration was determined from water by drying the water drops on CN-85 detectors and irradiating them with thermal neutrons.

Radon signals for geological explorations

Abstract Laboratory and field work concerning radon measurements have shown that radon signals can be used to locate oil, uranium deposits, faults, for earthquake prediction and many other studies. The SSNTD-Laboratory (PINSTECH) is carrying out experiments relating to radon diffusion/migration in different media of interest and is presently exploiting it for uranium exploration, earthquake predition and to locate geological faults in Pakistan.

Measurement of natural radioactivity in sand samples collected along the bank of rivers Indus and Kabul in northern Pakistan

Radioactivity is a part of the natural environment. The presence of natural radioactivity in sand and other building materials results in internal and external exposure to the general public. Therefore, it is desirable to determine the concentration of naturally occurring radionuclides, namely (232)Th, (226)Ra and (40)K in sand, bricks and cement which are commonly used as building materials in Pakistan. In this context, sand samples were collected from 18 different locations covering an area of ∼1000 km(2) along the banks of river Indus (Ghazi to Jabba) and river Kabul (Nowshera to Kund) in the northern part of Pakistan, whereas bricks and cement samples were collected from local suppliers of the studied area. In order to measure the specific activities in these samples, a P-type coaxial high-purity germanium-based gamma-ray spectrometer was used. In sand samples, the average specific activities of (226)Ra, (232)Th, and (40)K were found to be 30.5±11.4, 53.2±19.5 and 531±49 Bq kg(-1), whereas in brick samples, specific activities of 30±14, 41±21 and 525±183 Bq kg(-1) were observed, respectively. In cement samples, measured specific activity values were 21±5, 14±3 and 231±30 Bq kg(-1), respectively. Radium equivalent activities were calculated and found to be 143.8±38.6, 124±49.8 and 56.69±7 Bq kg(-1) for sand, brick and cement samples, respectively. The annual mean effective dose for the studied sand samples was found to be 0.40 mSv. External and internal hazard indices were less than unity for all the studied samples. The present results have been compared with those reported in the literature.

External dose assessment from the measured radioactivity in soil samples collected from the Islamabad capital territory, Pakistan

It is a well known fact that natural radionuclides are the major contributors towards the gamma ray exposure received by the general public. In this context, soil samples were collected from the Islamabad capital territory and activities due to (226)Ra, (232)Th, (40)K and (137)Cs were measured using gamma ray spectrometry: activities ranged from 41.5-106.2 Bq kg(-1), 4.0-193.8 Bq kg(-1), 325.3-657.4 Bq kg(-1) and 1.6-9.45 Bq kg(-1), respectively. From the measured activities, the external hazard index, internal hazard index, absorbed dose rate and mean annual effective dose were calculated. External and internal hazard indices were calculated as 0.76 and 0.95, respectively. The mean absorbed dose rate was found to be 130.97 nGy h(-1). The mean effective dose was estimated as 0.16 mSv y(-1), which is less than the maximum permissible dose of 1 mSv y(-1).

Radon — A measure of living standard

Abstract An experiment was carried out to measure the radon and its airborne daughter product levels in the bed rooms of 40 houses. The houses chosen for this experiment were constructed from same building material and the bed rooms chosen were approximately of similar dimensions. The main objective of this experiment was to study the living standards (e.g. ventilation of the houses) of the residents from the measured values of radon and its daughter product concentration levels. Our results indicate that, except for a few cases, one can predict the living habits of the occupants from the measured values of radon and its daughter concentration levels.