Radioactivity In Groundwater Research Articles

Radon radioactivity in groundwater from the Calabria region, south of Italy

In the present study the radon radioactivity in selected groundwater (boreholes and wells) from the Calabria region, south of Italy, was investigated. Water samples were analyzed by gamma spectrometry and by RAD7 + RAD H2O setup to determine the 222Rn activity concentration. Obtained values were used with the ingested dose conversion factor for 222Rn to estimate the annual effective dose for adult members of public due to consumption of the groundwater. The estimated average value was (88±5) μ Sv/y. It was compared with the estimated average annual effective dose due to ingestion of groundwater by the WHO (100 μ Sv/y) and that due to ingestion of food and water (290 μ Sv/y) by the UNSCEAR (2000). Results show that the presence of radon may not pose any radiological health hazard to the public due to the consumption of groundwater in the investigated region.

RADON IN GROUNDWATERS IN THE BAIKAL REGION AND TRANSBAIKALIA: VARIATIONS IN SPACE AND TIME

RADON IN GROUNDWATERS IN THE BAIKAL REGION AND TRANSBAIKALIA: VARIATIONS IN SPACE AND TIME

Distribution and sources of 226Ra in groundwater of arid region

As a part of characterizing radioactivity in groundwater of the eastern Arabian Peninsula, a first systematic evaluation of 226Ra activity in groundwater indicates a wide range (0.65–203.66 mBq L−1) with average of 17.56 mBq L−1. Adsorption/desorption process, groundwater residence time and uranium concentration are the main controlling factors of 226Ra distribution in groundwater of the different aquifers. Estimation of 226Ra effective dose from water ingestion suggests potential risk of drinking water from the carbonate aquifer.

Sorption properties of rocks on the territory of the former Semipalatinsk test site

The ability of granite and diorite, which are the most abundant rocks on the territory of the Semipalatinsk test site, to take up 137Cs and 90Sr present in tunnel waters of the Degelen mountain massif was studied in a laboratory. Experiments were performed both with simulated solutions and with real radioactive groundwater. The 137Cs distribution coefficients were found for samples of typical granites, albitized granite, quartz porphyry, and diorite from the former Semipalatinsk test site. The 137Cs distribution coefficient KD (cm3 g−1) was found to be n × 103–n × 104 for albitized granite, 60–80 for quartz porphyry, and 30–50 for granite. The ability of quartz porphyry and granite to take up 90Sr from simulated solutions is characterized by the distribution coefficients KD = 10–20 cm3 g−1, and that of albitized granite, by KD = 110−120 cm3 g−1. The data obtained are required for predicting the migration of long-lived fission products from the nuclear explosion with underground waters from central zones of underground nuclear explosions in the former Semipalatinsk test site and for calculating the mass transfer in specific geologic media.

Natural radioactivity in groundwater from the south-eastern Arabian Peninsula and environmental implications

Groundwater is the most valuable resource in arid regions, and recognizing radiological criteria among other water quality parameters is essential for sustainable use. In the investigation presented here, gross-α and gross-β were measured in groundwater samples collected in the south-eastern Arabian Peninsula, 67 wells in Unite Arab Emirates (UAE), as well as two wells and one spring in Oman. The results show a wide gross-α and gross-β activities range in the groundwater samples that vary at 0.01∼19.5 Bq/l and 0.13∼6.6 Bq/l, respectively. The data show gross-β and gross-α values below the WHO permissible limits for drinking water in the majority of the investigated samples except those in region 4 (Jabel Hafit and surroundings). No correlation between groundwater pH and the gross-α and gross-β, while high temperatures probably enhance leaching of radionuclides from the aquifer body and thereby increase the radioactivity in the groundwater. This conclusion is also supported by the positive correlation between radioactivity and amount of total dissolved solid. Particular water purification technology and environmental impact assessments are essential for sustainable and secure use of the groundwater in regions that show radioactivity values far above the WHO permissible limit for drinking water.

Radon in groundwater in Tumkur district of Karnataka with special reference to sampling sensitivity

Radon is a naturally occurring colourless and odourless radioactive gas that is soluble in water and is the main source of radioactivity of groundwater. Use of radon contaminated groundwater increased the radon levels in the air, especially in poorly ventilated houses, which is hazardous to health. Ingestion of such water for quite long period may lead to stomach cancer. The drinking water standards proposed by the Bureau of Indian Standards (BIS) exclude the permissible concentration of radon in drinking water. The US Environmental Protection Agency (USEPA) in 1991 proposed a Maximum Concentration Level (MCL) of 11.1 Bq/l for public water supply. The water samples from the bore wells in Tumkur district of Karnataka show radon concentrations in the range of 5 to 250 Bq/l. Ninety percentages of the samples show radon levels above the permissible limit as per USEPA. The spatial variation and geological control over radon concentration in groundwater in the area and sampling sensitivity are discussed here. The study was conducted during March 2012.

A method for determining the extent of bulk 210Po and 210Pb adsorption and retardation in aquifers

The naturally-occurring radionuclides 210Po and 210Pb are normally found in very low concentrations in the environment. However, under some conditions 210Po contributes significantly to the radioactivity in ground waters and can constitute a health risk. Naturally-occurring 210Pb can be used in predicting the behavior of contaminant Pb. While studies have identified the processes controlling 210Po and 210Pb behavior, the extent of adsorption and rates of removal in an aquifer cannot be determined without quantifying the rates of supply of these isotopes from decay of parent nuclides on and within aquifer solids. This study demonstrates how the isotope systematics of the 238U decay series, which includes 210Po and 210Pb, can be used to quantify the adsorption and retardation factors of 210Po and 210Pb in aquifers. The rates of 210Po and 210Pb supply to ground waters are determined from the concentrations of other radionuclides in the series, especially 222Rn, and so the distribution coefficients between aquifer solids and groundwater can be calculated. The effects of different supply rates due to different distributions of parent radionuclides in the aquifer can then be separated from differences in adsorption, which is controlled by aquifer water chemistry. A review of groundwaters where 210Po, 210Pb, and 222Rn data are available indicates that systematic variations can be found in bulk effective adsorption coefficients and retardation factors. Overall, a method is provided for future studies of 210Po and 210Pb behavior, and greater understanding of the occurrence and migration of these radionuclides.

Radioactivity in groundwater along the borders of Oman and UAE

Characterizing the quality and radioactivity of groundwater is vital as it represents valuable resource in arid regions. Here we present radioactivity level in groundwater collected from wells in a region along the border between Sultanate of Oman and United Arab Emirates (UAE). The aquifers are alluvium deposits (silt, sand and gravel) and the measured groundwater radioac- tivity (including 232 Th, 238 U, 235 U, 226 Ra, 222 Rn, gross-a and gross-b) indicates values below the WHO permissible limits for drinking water. The results also show large dif- ference in radioactivity fingerprints, in particular for 226 Ra and 222 Rn within the investigated aquifers. The data further indicate lower radioactivity in groundwater of the alluviums compared to the carbonate aquifers in the region. This feature makes the alluvium aquifers valuable reservoirs that should be carefully exploited as a source of groundwater. As this is the first investigation on the radioactivity of groundwater in alluvial aquifers in the region, it suggests that other alluvial deposits, particularly those inland and far from the marine water intrusion or seepage from carbonate rocks would have low radioactivity fingerprints.

Analysis of the non-thermophilic Crenarchaeota phylogeny in the swamp soil of Zoige plateau wetland

Zoige wetland of Tibetan plateau is a model low temperature ecosystem in a low latitude (33°56′N, 102°52′E) and high altitude region. Its organism has a unique phylogeny. To better evaluate the resource of the non-thermophilic Crenarchaeota in such an ecosystem, both restriction fragment length polymorphism (RFLP) and clone techniques were employed to study the diversity and phylogenetics of the non-thermophilic Crenarchaeota in the wetland soil. Archaeal 16S rRNA genes were amplified with the archaea-specific primers, and a library consisting of 240 clones was established. The non-thermophilic Crenarchaeota phylogenetic tree was constructed using the ARB phylogenetic analysis software. Based on the results of the RFLP experiments, the clones of all three Zoige wetland swamp soil samples were grouped into 16 different restriction cleavage patterns, all the clone coverage indices were above 91%, showing high library coverage. The correlations analysis indicated that the biodiversity of the non-thermophilic Crenarchaeota be positively correlated with soil moisture. The phylogenetic analysis revealed that all of the 16 Crenarchaeota sequences were clustered into two groups: 13 sequences in the Group 1.1b and 3 in the Group 1.3, similar to those archaeal sequences obtained from grassland soil, freshwater reservoirs, and seawater above boreholes, and radioactive groundwater and hot springs.

Natural Zeolite Permeable Treatment Wall for Removing Sr-90 from Groundwater

Experimental and modeling studies were completed to investigate the potential performance of a sorbing permeable treatment wall (PTW) comprised of natural zeolite for removal of strontium-90 (Sr-90) from groundwater at the West Valley Demonstration Project (WVDP) near Buffalo, NY. Multiple column tests were performed at the University at Buffalo (UB) and WVDP for periods ranging from 6 months to 2 years; UB columns were supplied with synthetic groundwater referenced to anticipated field conditions, while radioactive groundwater obtained on site was used for the WVDP columns. The primary focus was on quantifying the competitive cation reactions among five cations (Na(+), K(+), Ca(2+), Mg(2+), Sr(2+)) and Sr-90 with data obtained from the column studies used to estimate Gaines-Thomas (GT) selectivity coefficients. The resulting six-solute transport model provided flexibility to explore the influence of PTW parameters on long-term PTW performance, including variations in Sr-90 concentrations and groundwater geochemistry. The natural zeolite PTW is a viable method for in situ removal of Sr-90 from groundwater and potentially applicable to other sites contaminated by Sr-90.

The Natural Radioactivity in groundwater from selected areas in Greater Accra region of Ghana by gross alpha and gross beta measurements

Gross alpha and gross beta in 26 groundwater samples from Adentan to Abokobi areas in the Greater Accra Region of Ghana were determined using Alpha/Beta counting system (Canberra iMatic TM ). The average activity concentrations of gross alpha and gross beta were 0.034 and 0.501 Bq/L for Adentan, and 0.066 and 0.470 Bq/L for Abokobi, respectively. The results obtained are below the guideline levels of gross alpha (0.5 Bq/L) and gross beta (1.0 Bq/L) in drinking water established by the World Health Organisation. These results show that consumption of groundwater for the study areas may not pose any significant radiological health hazards through ingestion to the population.

Natural radioactivity of groundwater in Serbia

Activity concentrations of radionuclides 40K, 228Ra, 226Ra, 238U and Th232 and gross alpha and beta activities were analyzed in more than 100 samples of groundwater in Serbia. The highest gross alpha activity was recorded at 1.33 Bq/L (average 0.12 Bq/L), while the highest beta activity was 5.43 Bq/L (average 0.68 Bq/L). The potassium isotope 40K exhibited the highest active concentration (2.6 Bq/L) and was the largest contributor to the gross natural beta activity. Among the analyzed samples, 28 were found to have elevated beta activity concentrations, of which five samples also measured elevated alpha activity. All the groundwater samples that exhibited elevated radioactivity were of the HCO3-Na type and were genetically associated with granitic rocks. Their TDS levels and CO2 gas concentrations were also elevated.

Natural radioactivity in groundwater – a review

The issue of natural radioactivity in groundwater is reviewed, with emphasis on those radioisotopes which contribute in a significant way to the overall effective dose received by members of the public due to the intake of drinking water originating from groundwater systems. The term ‘natural radioactivity’ is used in this context to cover all radioactivity present in the environment, including man-made (anthropogenic) radioactivity. Comprehensive discussion of radiological aspects of the presence of natural radionuclides in groundwater, including an overview of current regulations dealing with radioactivity in drinking water, is provided. The presented data indicate that thorough assessments of the committed doses resulting from the presence of natural radioactivity in groundwater are needed, particularly when such water is envisaged for regular intake by infants. They should be based on a precise determination of radioactivity concentration levels of the whole suite of radionuclides, including characterisation of their temporal variability. Equally important is a realistic assessment of water intake values for specific age groups. Only such an evaluation may provide the basis for possible remedial actions.

Natural radionuclides in major aquifer systems of the Paraná sedimentary basin, Brazil

This paper describes the natural radioactivity of groundwater occurring in sedimentary (Bauru and Guarani) and fractured rock (Serra Geral) aquifer systems in the Paraná sedimentary basin, South America that is extensively used for drinking purposes, among others. The measurements of gross alpha and gross beta radioactivity as well the activity concentration of the natural dissolved radionuclides 40K, 238U, 234U, 226Ra, 222Rn, 210Po and 210Pb were held in 80 tubular wells drilled in 21 municipalities located at São Paulo State and its border with Mato Grosso do Sul State in Brazil. Most of the gross alpha radioactivity data were below 1 mBq/L, whereas values exceeding the gross beta radioactivity detection limit of 30 mBq/L were found. The radioelement solubility in the studied systems varied according to the sequence radon>radium>other radionuclides and the higher porosity of sandstones relatively to basalts and diabases could justify the enhanced presence of dissolved radon in the porous aquifer. The implications of the data obtained in terms of standards established for defining the drinking water quality have also been discussed. The population-weighted average activity concentration for these radionuclides was compared to the guideline value of 0.1 mSv/yr for the total effective dose and discussed in terms of the choice of the dose conversion factors.

Mapping radioactivity in groundwater to identify elevated exposure in remote and rural communities

A survey of radioactivity in groundwater (110 sites) was conducted as a precursor to providing a baseline of radiation exposure in rural and remote communities in Queensland, Australia, that may be impacted upon by exposure pathways associated with the supply, treatment, use and wastewater treatment of the resource. Radionuclides in groundwater, including 238U, 226Ra, 222Rn, 228Ra, 224Ra and 40K were measured and found to contain activity concentration levels of up to 0.71 BqL −1, 0.96 BqL −1, 108 BqL −1, 2.8 BqL −1, 0.11 BqL −1 and 0.19 BqL −1 respectively. Activity concentration results were classified by aquifer lithology, showing correlation between increased radium isotope concentration and basic volcanic host rock. The groundwater survey and mapping results were further assessed using an investigation assessment tool to identify seven remote or rural communities that may require additional radiation dose assessment beyond that attributed to ingestion of potable water.

Natural 3H radioactivity analysis in groundwater and estimation of committed effective dose due to groundwater ingestion in Varahi and Markandeya river basins, Karnataka State, India

The present study aimed at the assessment of natural tritium radioactivity in groundwater, being used for domestic and irrigation purposes in Varahi and Markandeya river basins. The study also intended to assess human health risk by estimating committed effective dose due to groundwater ingestion in the study area, taking into consideration the obtained tritium activity concentrations and annual water consumption. Tritium concentration of groundwater samples from the Varahi and Markandeya river basins were determined by liquid scintillation counting and the results laid in the range of 1.95 ± 0.25 to 11.35 ± 0.44 TU and 1.49 ± 0.75 to 9.17 ± 1.13 TU in Varahi and Markandeya river basins, respectively. Majority of the samples from Varahi (46.67%) and Markandeya (62.5%) river basins belong to modern water category aged between 5 and 10 years, while the remaining 53.33% and 37.5% of the samples from Varahi and Markandeya river basins respectively belong to sub-modern water with modern recharge, significantly influenced by precipitation and river inflowing/sea water intrusion. The effective committed dose for general public consumption considering the highest concentration value of 0.02 μSv year−1, which is very negligible compared to EPA (0.04 mSv year−1), WHO (0.1 mSv year−1), ICRP (1.0 mSv year−1) and UNSCEAR (2.4 mSv year−1) recommended dose limits, should not mean any additional health risk for the population living nearby.

The natural radioactivity in Guarani aquifer groundwater, Brazil

The measurements of gross alpha and gross beta radioactivity in groundwater samples from Guarani aquifer in Brazil are reported in this paper together with the activity concentration of the natural dissolved radionuclides 40K, 238U, 234U, 226Ra, 222Rn, 210Po, 210Pb, 232Th, 228Th, and 228Ra. Most of the gross alpha radioactivity values were below the critical level of detection corresponding to 1 mBq/L, however, the whole data set for the gross beta radioactivity and radionuclides 40K, 238U, 234U, 226Ra, 222Rn, 210Po, 210Pb, and 228Ra was submitted to a statistical treatment, considering class intervals arranged in geometric progression, because of the great variability of the activity. The analysis indicated lognormal distribution of the data, as usually observed in samples taken from the natural context. An inverse relationship between the gross alpha and gross beta activity has been identified and is related to an increase in the K content in the water. The mobility coefficient has been estimated for 238U, 226Ra, 232Th and 228Ra in Guarani aquifer and the results indicated that the radioelement solubility in the studied system varies according to the following order: radium>uranium>thorium. The implications of the data obtained in terms of standards established for defining the drinking water quality have also been discussed.

Natural radioactivity in groundwater and estimates of committed effective dose due to water ingestion in the state of Chihuahua (Mexico)

The activity concentration of 222Rn, 226Ra and total uranium in groundwater samples collected from wells distributed throughout the state of Chihuahua has been measured. The values obtained of total uranium activity concentration in groundwater throughout the state run from <0.03 up to 1.34 Bq l-1. Generally, radium activity concentration was <0.16 Bq l-1, with some exceptions; in spring water of San Diego de Alcalá, in contrast, the value reached approximately 5.3 Bq l-1. Radon activity concentration obtained throughout the state was from 1.0 to 39.8 Bq l-1. A linear correlation between uranium and radon dissolved in groundwater of individual wells was observed near Chihuahua City. Committed effective dose estimates for reference individuals were performed, with results as high as 134 microSv for infants in Aldama city. In Aldama and Chihuahua cities the average and many individual wells showed activity concentration values of uranium exceeding the Mexican norm of drinking water quality.

Interpretation of monte carlo simulations using parameter space plots.

Multimodal distribution functions that result from Monte Carlo simulations can be interpreted by superimposing joint probability density functions onto the contour space of the simulated calculations. The method is demonstrated by analysis of the pathway of a radioactive groundwater contaminant using an analytical solution to the transport equation. Simulated concentrations at a fixed time and distance produce multimodal histograms, which are understood with reference to the parameter space for the two random variables-velocity and dispersivity. Numerical integration under the joint density function up to the contour of the analytical solution gives the probability of contaminant exceeding a target concentration. This technique is potentially more efficient than Monte Carlo simulation for low probability events. Visualization of parameter space is restricted to two random variables. Nevertheless, analyzing the two most pertinent random variables in a simulation might still offer insights into the multimodal nature of output histograms.

Application of MnO2 coated scintillating and extractive scintillating resins to screening for radioactivity in groundwater

Manganese dioxide coated polyvinyltoluene (PVT) scintillating and extractive scintillating (ES) resins, which can be used to simultaneously separate and quantity radioactivity in aqueous solutions, were applied toward environmental screening applications. Off-line screening, utilizing a commercially available liquid scintillation counter (LSC) and on-line screening using a modified hand-held survey meter was evaluated in the laboratory for quantification of 99TcO4− and uranium in groundwater. The detection efficiencies for uranium with the MnO2 coated PVT resin were determined to be 17–37% and 7–27% for the LSC and survey instrument, respectively. The loading efficiency of the uranium out of groundwater ranged from 16% to 26%. In contrast, the detection efficiencies for 99Tc with the ES resin were determined to be 2–14% and 2–3% for LSC and hand-held survey meter, respectively, while the loading efficiency of the 99TcO4− in groundwater acidified to pH 2 was nearly 100%.