Estimation of radon concentration in soil and groundwater samples of Northern Rajasthan, India

Age-dependent potential health risk assessment due to radioactive radon-222 in the environs of highly populated Durgapur industrial zone and nearby Bakreswar hot spring, India

It is well known that exposure to a high concentration of radon-222 causes severe health effects, including cancer. The present article includes a survey on radon-222 in the water bodies of the city Durgapur [non-geothermal area] and nearby Bakreswar hot spring [geothermal province], India. The possible sources of radon from natural radionuclides and industries have been discussed in the article. Durgapur is a densely populated [~ 3680 persons/km2] industrial city with a population of 0.57 million. On the other hand, many tourists and pilgrims usually visit Bakreswar throughout the year. Age-dependent potential health risk assessments of the dwellers at Durgapur and Bakreswar due to radon exposure were performed for the first time. The present work is the first attempt to estimate the mean ingestion /and inhalation dose per annum, total effective dose [TED] per annum and the health risk assessment for cancer in adults, children and infants due to radon exposure at Durgapur and Bakreswar. In some cases, the values of TED exceed the permissible limit of 100 micro Sievert per year [µSv/y] as recommended by EUC and WHO. The radiation profile maps relating to radon concentration and associated contour maps of health risk factors [HRF] for the adults, children and infants were also prepared for the first time. Some areas were identified as high-risk zones, and the dwellers are prone to a high risk of cancer. The article also proposed several techniques to reduce radon in water and buildings. The authors also recommended banning some water sources to protect people from radon risk. This study will help scientists, policymakers, industrialists, farmers, government agencies and public health departments.

A comprehensive study of radon in drinking waters of Hanumangarh district and the assessment of resulting dose to local population

Study of radon concentration in drinking water from different sources (groundwater and surface water) used across the Hanumangarh district of Rajasthan, India, was done using scintillation-based detector. The concentration of radon in surface water varied from 0.12 to 2.07 Bq/l with an average value of 0.62 Bq/l and a standard deviation of 0.55 Bq/l and in groundwater samples varied from 1.61 to 8.73 Bq/l with an average value of 4.8 Bq/l and a standard deviation of 2.24 Bq/l. The ingestion and inhalation dose were calculated to assess the health risk for infants, children and adults. The resulting average annual effective dose has been found to be considerably lower than the recommended safe limit of 0.1 msv/y (WHO, In: Incorporating first and second addenda, third ed. WHO Press, Geneva. 3rd ed. World Health Organisation, Geneva, Switzerland, 2008). It can be concluded that radon in water does not pose a significant radiological health risk to the population of the studied area.

Assessment of soil-gas radon concentration over lithologies: a case study from district Karak, Khyber Pakhtunkhwa, Pakistan

The current study is aimed to determine the variation of soil-gas radon concentrations over different rock formations representing diverse lithologies in the district of Karak, Khyber Pakhtunkhwa, Pakistan. The stratigraphic units were grouped on the basis of lithological contents into four categories, i.e., limestone, evaporites, claystone/mudstone, and sandstone. The highest average soil-gas ²²²Rn concentration (544 Bq/L) was found in the uranium-bearing Dhok Pathan Formation of the Pliocene age, while the lowest radon levels (0.15 Bq/L) were observed in the salt-bearing strata of Bahadurkhel Salt of Eocene age showing the non-uraniferous nature of the salt. High radon potential associated with the Dhok Pathan Formation is likely to be related to the high degree of uranium mineralization which is contributing to the elevated soil-gas radon levels. The study revealed that the soil-gas radon concentration in all lithologies is varying in the order of RnSandstone > RnLimestone > RnClaystone/Mudstone > RnEvaporites with the highest radon levels in the sandstone unit of uranium-bearing Dhok Pathan Formation. High fluctuations of soil-gas radon levels observed in this study evidently show that lithology and uranium mineralization have strong control over the ²²²Rn concentrations.

Radon concentration measurement and effective dose assessment in drinking groundwater for the adult population in the surrounding area of a thermal power plant

Radon in the household water collected from hand pumps is measured using a continuous radon monitor. Water samples are collected from 25 villages from the surrounding regions of the National Capital Power Cooperation (NTPC), Dadri. The radon concentration ranges from 17±1 to 68±3 Bql^-1 with a mean value of 33±13 Bql^-1. The measured radon concentration in all collected samples lies well within the limit of 100 Bql^-1as set by the World Health Organization (WHO). The mean values of the annual effective dose due to ingestion of radon and due to the inhalation of radon released from water are 84±33 and 167±65 μSvy^-1, respectively. In addition, the mean values of estimated total annual effective doses are found to be 167±65 μSvy^-1. The mean value of total annual effective doses is found to be higher than the reference dose level of 100 μSvy^-1 recommended by the WHO and the United Nations Scientific Committee on the Effect of Atomic Radiation (UNSCEAR). The mean values of effective doses per annum to the lungs and stomach are 9.9±3.9 and 10.1±3.9 μSv, respectively.

Water radon risk in Susunia hill area: an assessment in terms of radiation dose

Radiological impact of radon in air is a global issue whereas radon in water has local consequences. Considering its importance, we have conducted a study on radon activity measurements in 316 tube-well water samples collected from Susunia hill area in Bankura district of West Bengal, India during the period of 25th December 2018-2nd February 2020. Radon contents are measured using AlphaGUARD radon monitor. The obtained radon activities in drinking water samples lie between 1.78 ± 0.07 and 3213.50 ± 77.32 Bq/l with an average of 128.30 ± 14.09 Bq/l. This study reveals that 93% of the samples have radon levels in excess of the USEPA proposed maximum contamination level (MCL) of 11.1 Bq/l while radon levels of 40% samples have exceeded the WHO and EU Council Directive recommended reference level of 100 Bq/l. The total annual effective dose of the samples have been estimated by considering the per day water intake of 3 l. The calculated total annual effective dose widely fluctuates between 10.39 and 18649.55 μSv/year with an average value of 744.59 μSv/year. 269 water samples have exceeded the WHO and EU Council Directive recommended reference level of 100 μSv/year. However, if we consider the UNSCEAR prescribed annual water intake of 60 l, the average dose becomes 279.82 μSv/year. The situation demands attention of the local authorities. Local people are advised to take some easy preventive measures for their radiological protection against such contamination.

OCCURRENCE AND DOSE FROM INTAKE OF RADON IN DRINKING GROUNDWATER IN OGUN STATE, NIGERIA

Radon-222 concentrations in groundwater from 10 local government areas (LGAs) of Ogun State were measured using AlphaGUARD radon detector and AquaKIT. The mean activity concentration of radon ranged from 1.23 ± 0.21 to 12.68 ± 18.11 Bq.l-1 corresponding to geometric means (GMs) of 1.22- 6.39 Bq.l-1. The radon concentrations of all the samples were below the World Health Organization and European Commission guidance level of 100 Bq.l-1, with 17% higher than 11.1 Bq.l-1, recommended by the United States Environmental Protection Agency. Mean annual effective dose due to ingestion ranged from 0.020 ± 0.004 to 0.254 ± 0.353 mSv.y-1 (adults), 0.041 ± 0.007 to 0.509 ± 0.705 mSv.y-1 (children) and 0.024 ± 0.004 to 0.297 ± 0.411 mSv.y-1 (infants). That of inhalation varied from 0.303 ± 0.053 to 3.108 ± 4.440 μSv.y-1. The mean annual effective doses of some of the LGAs were higher than the International Commission for Radiological Protection recommended reference dose level of committed effective dose of 0.1 mSv from 1-year consumption of drinking water.

Radiological Assessment of Indoor Radon and Thoron Concentrations and Indoor Radon Map of Dwellings in Mashhad, Iran

A comprehensive study was carried out to measure indoor radon/thoron concentrations in 78 dwellings and soil-gas radon in the city of Mashhad, Iran during two seasons, using two common radon monitoring devices (NRPB and RADUET). In the winter, indoor radon concentrations measured between 75 ± 11 to 376 ± 24 Bq·m⁻³ (mean: 150 ± 19 Bq m⁻³), whereas indoor thoron concentrations ranged from below the Lower Limit of Detection (LLD) to 166 ± 10 Bq·m⁻³ (mean: 66 ± 8 Bq m⁻³), while radon and thoron concentrations in summer fell between 50 ± 11 and 305 ± 24 Bq·m⁻³ (mean 115 ± 18 Bq m⁻³) and from below the LLD to 122 ± 10 Bq m⁻³ (mean 48 ± 6 Bq·m⁻³), respectively. The annual average effective dose was estimated to be 3.7 ± 0.5 mSv yr⁻¹. The soil-gas radon concentrations fell within the range from 1.07 ± 0.28 to 8.02 ± 0.65 kBq·m⁻³ (mean 3.07 ± 1.09 kBq·m⁻³). Finally, indoor radon maps were generated by ArcGIS software over a grid of 1 × 1 km² using three different interpolation techniques. In grid cells where no data was observed, the arithmetic mean was used to predict a mean indoor radon concentration. Accordingly, inverse distance weighting (IDW) was proven to be more suitable for predicting mean indoor radon concentrations due to the lower mean absolute error (MAE) and root mean square error (RMSE). Meanwhile, the radiation health risk due to the residential exposure to radon and indoor gamma radiation exposure was also assessed.

A fast method for the simultaneous determination of soil radon (222Rn) and thoron (220Rn) concentrations by liquid scintillation counting

This paper presents a fast method dedicated to measurements of radon nuclides in the soil gas. The soil gas is sampled by a typical hollow tube probe by 10 min of sucking of about 3 dm³ of gas and passing it directly through a 16 cm³ of water-immiscible liquid scintillator placed in a typical 20 cm³ scintillation vials, where the radon and thoron nuclides are effectively absorbed. Most of the presently used active methods for radon isotopes determination (e.g., RAD7 or AlphaGuard) require the soil gas transfer to the measuring device. The serious limitation of such approach is the necessity to wait until the radon daughter isotopes decay, before counter is ready for the next measurement. In the proposed method, several samples can be simultaneously gathered from the examined areas in the form of the scintillation vials, which are ready for later measurements in the automatic liquid scintillation counters in the lab or directly in situ. For that purpose, the combined mathematical model for the simultaneous radon and thoron determination has been elaborated. The direct in situ measurements of the sample activity between 60 and 240 s after the end of sampling followed by a second activity measurement after 3 h allow for the determination of both ²²⁰Rn and ²²²Rn concentrations in the soil gas. The limit of detection for ²²²Rn isotope during 10 min counting is 25 Bq·m^-3, whereas for a 3 min counting of ²²⁰Rn just after sampling was found to be ca. 150 Bq·m^-3. The method was successfully verified and applied for the simultaneous radon and thoron concentrations measurements in the soil gas in Central Poland region.

ASSESSMENT OF RADON IN SOIL AND WATER IN DIFFERENT REGIONS OF KOLHAPUR DISTRICT, MAHARASHTRA, INDIA

Researchers have already established that inhalation of high radon concentration is hazardous to human health. Radon concentration has been measured in water and soil, in various part of Kolhapur district has been carried out by the AQTEK Smart RnDuo which is an active device technique. The observed minimum value of the radon mass exhalation rate of the soil is 13.16 ± 0.83 mBq/kg/h and maximum is 35.11 ± 1.84 mBq/kg/h. The minimum value of the Radon concentration in water is 0.33 ± 0.052 Bq/L and maximum is 7.32 ± 0.078 Bq/L. These values of radon concentration are below the action of recommended level by the USEPA, which is set as the maximum contaminant level of 11.1-148 Bq/L of radon in drinking water. Total annual effective dose rate of water is 11 μSv/y. The purpose of present study is to assess radiological risk from consumption of water that provide in Kolhapur district and to evaluate the radon mass exhalation rate of soil in few places of Kolhapur district.

Radon Concentration Measurement in Groundwater of Roorkee, Uttarakhand, India

Groundwater is the largest fresh water resource and radon is a radioactive naturally occurring noble gas that may be found anywhere in soil, air and water due to decay of uranium in rocks. It is important to investigate the radon in groundwater to safeguard against the health hazard caused due radon. The results presented here are from radon concentrations measured using RAD7 detector in 9 representative groundwater samples collected from hand pumps from southern parts of Roorkee in Haridwar district of Uttrakhand. Radon activity concentration was found in the range of 0.55+0.22 Bq L-1 to 3.39+0.28 Bq L-1 with an average value of 2.16+0.37 Bq L-1. Radon values were compared with United State Environmental Protection Agency value of 11 Bq L-1. The radon activity trend was found within the permissible limit.