Seasonal variation of indoor radon/thoron and their progeny levels in lesser-Himalayas of Jammu & Kashmir,India

In this investigation, the passive estimation of radon (Rn²²²), thoron (Rn²²⁰) and their progenies have been measured in the dwellings of Reasi district of Jammu & Kashmir for a period of 1 year. These estimations have been done with the help of latest developed single entry Pin-hole based dosimeters and progeny sensors based on deposition. The annual Equilibrium factors for ²²²Rn, ²²⁰Rn, and their progenies have been calculated separately for each dwellings The average annual effective dose was found to be 0.9 ± 0.2 mSv/y for ²²²Rn, which is less than prescribed limit of ICRP. The results obtained indicate no vital health hazards because of exposure of Rn²²², Rn²²⁰ and their progenies.

     

Radon measurements in groundwater

A device was developed for the collection, containment, and bubbling of radon from groundwater samples to facilitate concentration measurements in the field without the need for fragile glassware. Wellwater supplies were collected in high-potential areas of New York State in a comparison of the device with traditional methods (liquid scintillation and laboratory-based Lucas-cell counters). Waterborne radon levels to 4100 Bq L^–1 reveal the potential contribution to indoor air from everyday water use in a home, as levels of 1500 Bq L^–1 contribute about 150 Bq m^–3 (the EPA-recommended limit) to indoor-air radon levels. With a Geographic Information System (GIS), spatial coordinates from each site are used to correlate concentrations with bedrock geology.     

室内空气氡检测技术进展

地球上氡来自于放射性元素的衰变,氡无色无味,在地下密闭空间中的浓度高低依赋存条件变化差异很大. 欧盟和我国对室内氡水平有较为严格的要求,分别为50 Bq/m³和100 Bq/m³. 氡具有放射性,其半衰期为3.83 d,衰变的子体多为金属,仍具有放射性. 人员长期暴露于氡浓度水平较高的环境中,会因氡和衰变子体的放射性引发内照射使滞留在这些空间中的人员受到放射性沾染,引发各种病症,多见为呼吸系统肿瘤. 较为详尽的综述了近年来国内外对室内氡污染水平,特别是典型地下密闭空间氡污染水平的研究,并重点介绍了地铁（1.2~166.5 Bq/m³）、典型坑道（105.3~4 434.2 Bq/m³）、矿井（1 952~5 121 Bq/m³）、国防工程（39~17 169 Bq/m³）、地下实验室（28~482 Bq/m³）的氡污染水平. 已有研究表明,在一些通风不畅或者较难通风的密闭空间中氡超标比较严重. 还介绍了近年来国内外密闭空间内氡防护和去除技术研究的发展情况,分析了各种技术的特点,提出隔离防氡和变压吸附分离富集去除氡是较为可行和应重点发展的研究方向.     

Population Structure Analysis and Selection of Core Set among Common Bean Genotypes from Jammu and Kashmir,India

Understanding the genetic diversity of a crop is useful for its effective utilization in breeding programmes. For better understanding of the genetic variability in common bean, the first and foremost step is to study its genetic diversity. In the present investigation, 138 genotypes of common bean collected from various regions of Jammu and Kashmir, India, representing major common bean growing areas of this region, were evaluated using 23 SSRs. These SSRs were found highly polymorphic and possess high values for various parameters indicating their high discriminatory power. The average PIC value observed was 0.692, with 0.730 as average gene diversity value, and 0.267 as heterozygosity. Twenty-three SSRs produced a total of 251 alleles. The dendrogram generated with un-weighted neighbour joining cluster analysis grouped genotypes into three main clusters with various degrees of sub-clustering within the clusters. The model-based STRUCTURE analysis using 23 SSR markers identified a population with 3 sub-populations which corresponds to distance-based groupings with average F _ST value and expected heterozygosity of 0.1497 and 0.6696, respectively, within the sub-population, as such high level of genetic diversity was observed within the population. Further, Core Hunter II was used to identify a core set of 96 diverse genotypes. This core set of diverse 96 genotypes is a potential resource for association mapping studies and can be used by breeders as a material to make desirable genetic crosses to generate elite varieties for the fulfilling global market needs. These findings have further implications in common bean breeding as well as conservation programs.     

Radon concentration in groundwater of Varahi and Markandeya river basins, Karnataka State, India

The present study presents an overview of the distribution of radon (²²²Rn) activity concentration in the groundwater samples and their annual effective dose exposure in the Varahi and Markandeya command areas. Radon measurement was made using Durridge RAD-7 radon-in-air monitor, using RAD H₂O technique with closed loop aeration concept. The measured ²²²Rn activities in 16 groundwater samples of Varahi command area ranged between 0.2 ± 0.4 and 10.1 ± 1.7 Bq L⁻¹ with an average value of 2.07 ± 0.84 Bq L⁻¹, well within the EPA’s maximum contaminant level (MCL) of 11.1 Bq L⁻¹. In contrast, the recorded ²²²Rn activities in 14 groundwater samples of Markandeya command area found to vary from 2.21 ± 1.66 to 27.3 ± 0.787 Bq L⁻¹ with an average value of 9.30 ± 1.45 Bq L⁻¹. 21.4% of the samples (sample no. RMR5, RMR11 and RMR12) in the Markandeya command area exceeded the EPA’s MCL of 11.1 Bq L⁻¹ and it was found that some samples in both the command areas were found to have radon values close to MCL value. The spatial variation in the radon concentration in the Varahi and Markandeya command area were delineated by constructing the contour map. The total annual effective dose resulting from radon in groundwater of both Varahi and Markandeya command areas were significantly lower than the UNSCEAR and WHO recommended limit for members of the public of 1 mSv year⁻¹.     

Radon exhalation rate and indoor exposure in a Brazilian coal mine

Journal of Radioanalytical and Nuclear Chemistry - Radionuclides in mineral coal and related rocks are of great concern to the human health, among them the radon gas, as it has been considered the...     

Dose assessment from exposure to radon,thoron and their progeny concentrations in the dwellings of sub-mountainous region of Jammu & Kashmir,India

The present work deals with the assessment of annual inhalation dose due to exposure of indoor radon, thoron and their progeny concentrations in the villages situated in sub-mountainous region of Jammu & Kashmir, India. The distribution of the data and the homogeneity of medians among different seasons and dwellings were assessed with the Shapiro–Wilk test and the Mann–Whitney test. The estimated total annual inhalation dose in these villages varied from 0.5 to 1.9 mSv year^?1 which is less than the prescribed limit by ICRP (2008). Thus, the investigated area is safe from irradiation of radon, thoron and their progeny.     

Radon isotope assessment of submarine groundwater discharge (SGD) in Coleroon River Estuary,Tamil Nadu,India

Submarine groundwater discharge is the fresh groundwater discharge to sea that impacts the coastal regions. Radon (²²²Rn) isotope has been used to quantify SGD in coleroon river estuary, India. Continuous ²²²Rn analyses were attempted for 10 days in groundwater and pore water samples at three different locations. ²²²Rn in groundwater ranges between 35.0 and 222.0 Bq m^?3 and in pore water between 14.0 and 150.0 Bq m^?3 irrespective of locations. The radon mass balance estimated total SGD rate ranges between 2.37 and 7.47 m days^?1. The SGD increases with distance from coast, influenced by tides and hydrological features.     

Radon as a tracer to determine the mean residence times of groundwater in decontamination reactors

The groundwater at a former gasoline production site in Germany is heavily contaminated with aromatic hydrocarbons (mostly benzene) and is currently being treated in bioreactors under anaerobic conditions. To determine the reaction kinetics it is essential to know the mean residence time of the groundwater in these reactors. Most of the commonly used tracers (dyes and salts) did not give reliable results because of their interaction with the mineral matrix in the reactors. In this study radon (²²²Rn) dissolved in the groundwater is used as the tracer. The flow rate of groundwater through the reactors is 1 l/h. Over a period of 8 hours the radon-spiked groundwater was injected into the natural groundwater which has a very low radon concentration. The radon concentration of the discharged water is measured online at the reactor outlet. An increasing radon concentration at the reactor exit indicates the shortest residence time of the water. The time-dependent progress of the radon concentration provides detailed information about the flow behavior and residence times of water in the reactor.     

A case study on the effect of water from groundwater sources on indoor radon levels

Indoor airborne radon concentration released from water was estimated over several months based on experimental measurements. When heated water including radon was used, the radon level became high in the entire house. Filling the bathtub with hot water had a strong effect on the indoor radon level. In winter, the indoor radon concentration was high due to windows being closed. The radon transfer coefficient was estimated 2.5·10⁻⁴ in this test house. This is 2.5 times higher than the average radon transfer efficiency estimated by UNSCEAR.     

Radon concentration in dwellings in Aomori Prefecture, Japan

To obtain an average dose from ²²²Rn to the people in Aomori Prefecture where the first Japan"s nuclear fuel cycling facilities are now under construction, we surveyed ²²²Rn concentrations in 109 dwellings in the Prefecture from 1992 to 1996. The outdoor ²²²Rn concentrations were also measured in gardens of 15 dwellings. The ²²²Rn concentrations were measured with passive ²²²Rn detectors which used a polycarbonate film for counting a-ray and could separate concentrations of ²²²Rn from ²²⁰Rn. Counting efficiencies of the detectors were calibrated with a standard ²²²Rn chamber in the Environmental Measurement Laboratory in USA and in the National Radiological Protection Board in UK. Geometric means of ²²²Rn concentration were 13 and 4.4 Bq^.m^-3 in the dwellings and outdoor, respectively. These values were consistent to nationwide survey results in Japan. The ²²²Rn concentrations in the dwellings depended on their age. The concentrations were higher in recent dwellings than in older ones. The radiation dose from ²²²Rn was estimated, taking into account the occupancy factor for inside and outside of dwellings. The annual dose was 0.32 mSv^.y^-1, and 99% of the dose came from the exposure to ²²²Rn inside the dwelling.     

Fallout from Chernobyl in Bologna and its environs: Radioactivity in airborne,rain water and soil

The Chernobyl fallout was estimated in Emilia-Romagna, a Northeastern region of Italy. Nuclide composition of airborne and the time evolution of the radioactivity were investigated. The comparison of the activity ratio of¹⁰³Ru to¹³⁷Cs allows to conclude that Italy was not influenced by the first release. The trend of the total activity and¹³⁷Cs percentage in rain water was very similar to those of air particulates. A calculation model to estimate¹³⁷Cs deposition onto the ground has been developed and validated by comparison of the calculated and experimental values for soil samples. The activity range was 2–40 kBq ·m^–2.     

Assessment of pollution level in a Himalayan Lake,Kashmir, using geomatics approach

Pollution indices aggregate concentrations of several water quality parameters into a single quantity to indicate the general status of pollution in a region. In this study, a variant of the previous water quality index was used to evaluate the pollution status in the Wular Lake, Kashmir, which is a Ramsar site and wetland of international importance. The index termed as water quality status index (WQSI) is considered as a simple pollution indicator to support management actions in the Wular Lake, Kashmir. WQSI is a valuable and unique rating to depict the overall water quality status and pollution level of the waterbody in a spatial context and is also capable of dealing with those water quality parameters which do not have well-developed standard values. In this study, the water quality of the Wular Lake was investigated in June 2013 for 21 sample locations. The index used in this work is composed of 13 measurable physico-chemical parameters – pH, dissolved oxygen, chemical oxygen demand, biological oxygen demand, alkalinity, hardness, chloride, total dissolved solids, ammonia, iron, nitrite, nitrate and fluoride. The generation of WQSI is based on weighted overlay technique, in which interpolated raster maps were generated for all the 13 water quality parameters and weights are assigned to each and every parameter using analytic hierarchy process technique, considering their status as benefit or cost criteria. Based on the value of WQSI, the whole lake was divided into five zones, comprising least polluted zone (23%), moderately polluted zone (20%), high polluted zone (30%), very high polluted zone (22%) and extremely polluted zone (5%). From this study, it has been found that 60 km² (77%) of total lake area constitutes the moderate to extremely polluted zone and only 18 km² (23%) of the total lake area constitutes the least polluted zone, which is in the north-west region of the lake. The study reveals that the world-famous Wular Lake is undergoing the eutrophication process and as a result of which the lake is losing its water holding capacity to deal with the disastrous flood problem in Kashmir region.     

Radon Mapping of Soils in St. Elizabeth, Jamaica

Soil gas measurements of radon were made in St. Elizabeth, Jamaica using nuclear track etch detectors. The results were compared to gamma-ray spectroscopy measurements made in the laboratory on soil samples collected at the radon measurement sites. An assessment of the degree of disequilibrium of uranium and thorium was also made by comparison with neutron activation analysis, delayed neutron counting and equivalent uranium and thorium measurements. The results to date for equivalent uranium and radon show a strong correlation and indicate the possibility of soil radon mapping in Jamaica using gamma-ray spectroscopy. Three anomalous sites have been identified.     

Radon flux variability with season and location in Tasmania, Australia

Radon (²²²Rn) and thoron (²²⁰Rn) fluxes were measured in locations in Tasmania and Victoria. Emphasis was on an evaluation of seasonal variability of the fluxes. The work is the first part of a program of mapping radon and thoron fluxes in the island of Tasmania on a scale commensurate with requirements of modelling the behaviour of environmentally important trace gases in a limited area around the Baseline Air Pollution Station at Cape Grim, Tasmania.     

Radon in schools and dwellings of Osijek

Indoor radon concentrations were measured in 10 821 pupils primary schools of Osijek by means of the Radhome silicon detector. The values ranged from 15 to 300 Bq/m³ with the arithmetic and geometric means of 93.4 and 70.6 Bq/m³, respectively. Ten years continuous radon measurements performed with the LR-115 nuclear track detector in three houses of different construction and town area gave means of 27, 96 and 23 Bq/m³; the indoor Rn concentration for a heating period was a factor of 1.5 higher than for the warm season. The average effective dose equivalent for the primary school pupils was 2.8 mSv/y (with occupancy factors of 0.6, 0.2 and 0.2 for home, school and outdoors, respectively). For citizens of Osijek it was 1.7 mSv/y.