Radium isotopes in Na-Cl type groundwater from the Japan Sea side of Japan, Central Japan (original) (raw)
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Radium, radon and inert gases in groundwaters and rocks as geochemical tracers
1980
Variation of the Rn contents of groundwaters has been used as an indicator of aquifer variability. The relative importance of intergranular and fissure flow and the variation 222 in efficiency of Rn release into groundwaters has been 222 investigated. The fraction of Rn released from rocks has been 222 determined and the mechanisms by which Rn is released from (ii) sandstone, limestone and granite rock fragments has been 226 discussed. Variability of the Ra contents of groundwaters has been explained in terms of the relative importance of the recoil and etch mechanisms of solution and the solubility of 226 Ra salts in groundwaters.
Applied Geochemistry, 2012
A total of 1270 raw-water samples (before treatment) were collected from 15 principal and other major aquifer systems (PAs) used for drinking water in 45 states in all major physiographic provinces of the USA and analyzed for concentrations of the Ra isotopes 224 Ra, 226 Ra and 228 Ra establishing the framework for evaluating Ra occurrence. The US Environmental Protection Agency Maximum Contaminant Level (MCL) of 0.185 Bq/L (5 pCi/L) for combined Ra ( 226 Ra plus 228 Ra) for drinking water was exceeded in 4.02% (39 of 971) of samples for which both 226 Ra and 228 Ra were determined, or in 3.15% (40 of 1266) of the samples in which at least one isotope concentration ( 226 Ra or 228 Ra) was determined. The maximum concentration of combined Ra was 0.755 Bq/L (20.4 pCi/L) in water from the North Atlantic Coastal Plain quartzose sand aquifer system. All the exceedences of the MCL for combined Ra occurred in water samples from the following 7 PAs (in order of decreasing relative frequency of occurrence): the Midcontinent and Ozark Plateau Cambro-Ordovician dolomites and sandstones, the North Atlantic Coastal Plain, the Floridan, the crystalline rocks (granitic, metamorphic) of New England, the Mesozoic basins of the Appalachian Piedmont, the Gulf Coastal Plain, and the glacial sands and gravels (highest concentrations in New England).
A rapid and inexpensive method for 226 Ra and 228 Ra measurements of high TDS groundwaters
c Laboratory had to evaluate 226 Ra and 228 Ra in thousands of groundwater samples. c Samples had to be done quickly and contained high iron and total dissolved solids (TDS). c Paper details development of a simple method based on ion exchange and gamma spectrometry. c Side-by-side comparison to an alpha spectrometry method showed excellent agreement. a b s t r a c t A series of laboratory-scale studies was conducted by preconcentrating 226 Ra from spiked water test samples using Purolite ion-exchange resin to evaluate the adsorption efficiency of the resin under varying conditions. After removing the resin from the columns, it was sealed in gas-tight containers and measured via gamma spectrometry. The Purolite resin showed high radium uptake and retention from natural waters in the presence of high iron and total dissolved solids (TDS). This procedure allowed us to process a large number of high TDS samples at a typical rate of 15 samples/day using three germanium detectors. Quality assurance and method validation have been achieved by analyzing selected groundwater samples, with different 226 Ra activities and high TDS values, and comparing the results to those using alpha spectrometry with a 133 Ba yield tracer. There was very good agreement between the obtained 226 Ra activities by both methods.
The occurrence of 226 Ra and 228 Ra in groundwaters of the Polish Sudety Mountains
2002
The paper presents preliminary measurement results of the concentrations of 226 Ra and 228 Ra isotopes in the groundwaters of the Polish part of the Sudety Mountains. The analysis of sampling results for water from 55 intakes showed that the average concentrations amount to 0.144 Bq/dm 3 for 226 Ra and 0.083 Bq/dm 3 for 228 Ra, while the extreme values reach 0.007 and 0.92 Bq/dm 3 for 226 Ra, and 0.004 and 0.4 Bq/dm 3 for 228 Ra. The activity ratio 228 Ra/ 226 Ra in the examined groundwaters ranges between 0.099 and 2.059. The result of the conducted research implies that the highest concentrations of 226 Ra and 228 Ra occur in the waters with the highest general mineralization (the highest values of total dissolved solids (TDS)).
Radium-226 concentration in spring water sampled in high radon regions
Applied Radiation and Isotopes, 2010
Water 226 Ra concentration in springs was measured in regions with high indoor radon: Ural, North Caucasus (Russia), Niska Banja (Serbia), Piestany (Slovakia), and Issyk-Kul (Kyrgyzstan). This paper presents the results for 226 Ra concentration above 0.03 Bq l-1. Radium in water could indicate indoor radon problem in the region and water investigation is useful at the initial stage of radon survey. Even low 226 Ra concentration in water (0.1-0.6 Bq l-1) caused high 226 Ra activity in travertine (up to 1500 Bq kg À 1), which resulted in indoor radon concentration above 2000 Bq m À 3 (Niska Banja).
Geology, Geophysics & Environment, 2016
The influences of aquifer formations and water chemical composition on the occurrence and activity ratio of radium isotopes in groundwater are discussed. Based on the model of desorption/adsorption processes of natural radionuclides in the rock-water system, the concentrations of radium isotopes and their activity ratio in groundwater are evaluated by the numerical Monte Carlo method (MC). In cases where the groundwater is of a similar age, limited flow (up to several meters/year), the physical conditions and the uranium and thorium activity ratios in host water formations are similar, the activity concentrations of radium isotopes (226 Ra, 228 Ra) and their activity ratio (226 Ra/ 228 Ra) are the highest in the water of high desorption coefficient for chloride sodium water (domination of Cl − , Na + ions), medium in water of moderate desorption (bicarbonate water-HCO 3 − , Ca 2+) and the lowest in waters with a low desorption coefficient (sulfate ions prevailing-SO 4 2− , Ca 2−). The statements are well confirmed in the case of the natural mineral waters from the Polish Outer Carpathians. The total dissolved solids (TDS) of the Polish Carpathians waters varies from several hundred milligrams per liter to several tens of thousands milligrams per liter.
Radium isotopes and 222ptt in shallow brines, Kharaghoda
Chemical Geology ( …, 1991
The concentrations of Ra isotopes (t'oRa,223Ra,228Ra and 226Ra) and 222Rn have been determined in brines from Kharaghoda, western India. The Ra isotopes concentrations in these samples are orders of magnitude higher than that reported in potable groundwaters. The 22aRa activities lie between 28 to 277 dpm per kg; about 4olo to 9606 of that expected from its production, calculated using 222Rn as a recoil flux monitor. The low 1224Ra/222Rn] activity ratios are typical of less saline brines. Retardation factors for Ra in these brines, derived from the 222Rn-22aRa-228Ra system and based on a reversible exchange model, are in the range of about 0.3-l 14. These values are 3-4 orders of magnitude lower than that in potable groundwaters. The residence time of Ra in Kharaghoda brines is approximately one day. Our data suggest that in briny aquifers Ra is considerably less'particle-reactive'than in potable groundwaters. The retardation factor for Ra shows a strong negative correlation with salinity. This anticorrelation suggests that salinity would play a crucial role in determining the mobility of Ra and its geochemical homologues through groundwater systems.
SN Applied Sciences
A new method for estimating retardation factor and recoil constant of radium isotopes in groundwater hosted in porous aquifers is described. The method is based on the evidence that alpha-recoiled radium ions, supplied by thorium parent atoms which occur in phases immersed in NAPL (Non-Aqueous Phase Liquids), are not adsorbed on solid phases. Experimental evidence is given that manganese dioxide, zeolite 4A, natural clay, monazite and weathered volcanic rock, all phases normally adsorbing radium from aqueous solutions, when immersed in NAPL adsorb negligible amounts of radium. This allows using experimental data on rock samples, representative of porous aquifers, for estimating Ra retardation factor and its alpha recoil constant in groundwater, without using Rn data as a comparison term. Unlike estimation of retardation factor between the "NAPL method" and the method based on comparison with radon depends on the different process of entry from aquifer rock into groundwater for radon and radium. Precise estimates of retardation factor and recoil constants of radium allow to apply equations ruling the temporal evolution of radium isotopes in groundwater and to determine its age. Implications, useful for measuring the contamination age of soils by NAPL fluids, are described as well.