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PubMed1993

The analysis of naturally-occurring radionuclides from uranium and thorium decay series in table mineral waters.

This project required the highly sensitive analysis of low-level alpha- and beta-emitters naturally occurring in table mineral water sold on the Swiss market. These radionuclides occur in the three major decay series-uranium-238, uranium-235, and thorium-232. The radionuclides analysed were 238U, 235U, 234U, 232Th, 230Th, 228Th, 210Po, 210Pb, and 226Ra. Many other radionuclides were determinable as a result of their equilibrium with an analysed nuclide. Efficient, element specific separation techniques were developed, allowing for the spectral analysis of each element without interference from other radioactive elements. Radioactive tracers, 232U, 230Th, and 209Po, were necessary to determine the percentage yield. These yields often varied greatly between different mineral waters, especially for thorium, ranging from 30 to 100%. Uranium, thorium and polonium isotopes could be directly analysed for by alpha-spectrometry. 226Ra was determined through the ingrowth of its daughter 222Rn by liquid scintillation counting. From the samples remaining after 210Po removal, the isotope's re-ingrowth from 210Pb determined the original 210Pb content. Limits of detection ranged from 0.1 to 2.0 mBq/l. The following contents were determined 234U + 238U 30-720 mBq/l; 232Th + 230Th < 1-5 mBq/l; 228Th 2-40 mBq/l; 226Ra 5-370 mBq/l; 210Po 1-90 mBq/l; 2,0Pb 1-90 mBq/l.

Mineral Waters↗
PubMed1988

Radioactive artifacts: historical sources of modern radium contamination.

Radium has been distributed in a wide variety of devices during the early part of this century. Antique objects containing significant amounts of radium turn up at flea markets, antique shows, and antique dealers, in a variety of locations. These objects include radium in devices which were used by legitimate medical practitioners for legitimate medical purposes such as therapy, as well as a wide variety of "quack cures." These devices may contain anywhere from a few nanocuries to as much as several hundred microcuries of radium. In addition to medical sources, a large variety of scientific instruments utilize radium in luminous dials. These instruments include compasses, azimuth indicators, and virtually any object which might require some form of calibration. In addition, the consumer market utilized a large amount of radium in the production of wrist watches, pocket watches, and clocks with luminous dials. Some of these watches contained as much as 4.5 microCi of radium, and between 1913 and 1920 about 70 gm was produced for the manufacture of luminous compounds. In addition to the large amount of radium produced for scientific and consumer utilization, there were a number of materials produced which were claimed to contain radium but in fact did not, further adding to the confusion in this area. The wide availability of radium is a result of the public's great fascination with radioactivity during the early part of this century and a belief in its curative properties. A number of objects were produced in order to trap the emanations of radium in water for persons to drink in order to benefit from their healing effects. Since the late 20s and early 30s the public's attitude towards radiation has shifted 180 degrees and it is now considered an extremely dangerous and harmful material. However, even as late as the 1950s, there were still some items produced containing radioactivity which today would be unthinkable. The "Buck Rogers Mystery Ring" of the 1950s was activated with polonium. With the shift in public attitudes towards radioactivity, and increasing problems in disposal of radioactive materials, the disposal of radium presents a particularly perplexing problem. The radium which was produced in the early part of the century is still around in various forms and is extremely difficult to dispose of. All objects discovered claiming to contain radium should be taken seriously and should be properly surveyed.(ABSTRACT TRUNCATED AT 400 WORDS)

Equipment and Supplies↗
PubMed2001

An estimation of radiation doses to benthic invertebrates from sediments collected near a Canadian uranium mine.

A new method is described for calculating radiation doses to benthic invertebrates from radionuclide concentrations in freshwater sediment. Both internal and external radiation doses were estimated for all 14 principal radionuclides of the uranium-238 decay series. Sediments were collected from three sites downstream of a uranium mining operation in northern Saskatchewan, Canada. Sediments from two sites, located approximately 1.6 and 4.4 km downstream from mining operations, yielded absorbed doses to both larval midges, Chironomus tentans, and adult amphipods, Hyalella azteca, of 59-60 and 19 mGy/year, respectively, compared to 3.2 mGy/year for a nearby control site. External beta radiation from protactinium-234 (234Pa) and alpha radiation from uranium (U) contributed most of the dose at the impacted sites, whereas polonium-210 (210Po) was most important at the control site. If a weighting factor of 20 was employed for the greater biological effect of alpha vs. beta and gamma radiation, then total equivalent doses rose to 540-560 mGy/year at the site closest to uranium operations. Such equivalent doses are above the 360-mGy/year no-observed-effect level for reproductive effects in vertebrates from gamma radiation exposure. Data are not available to determine the effect of such doses on benthic organisms, but they are high enough to warrant concern. Detrimental effects have been observed in H. azteca at similar uranium concentration in laboratory toxicity tests, but it remains unclear whether the radiotoxicity or the chemotoxicity of uranium is responsible for these effects.

Animals↗
PubMed2001

Exposure of workers in mineral processing industries in Brazil.

The mining, milling and processing of uranium and thorium bearing minerals may result in radiation doses to workers. A preliminary survey pilot program, that included six mines in Brazil (two coal mines, one niobium mine, one nickel mine, one gold mine and one phosphate mine), was launched in order to determine the need to control the radioactive exposure of the mine-workers. Our survey consisted of the collection and analysis of urine samples, complemented by feces and air samples. The concentrations of uranium, thorium and polonium were measured in these samples and compared to background data from family members of the workers living in the same dwelling and from residents from the general population of Rio de Janeiro. The results from the coal mines indicated that the inhalation of radon progeny may be a source of occupational exposure. The workers from the nickel, gold and phosphate mines that were visited do not require a program to control internal radiological doses. The niobium mine results showed that in some areas of the industry exposure to thorium and uranium might occur.

Brazil↗
PubMed1998

Extractive procedure for uranium determination in water samples by liquid scintillation counting.

An extractive procedure for uranium determination using liquid scintillation counting with the URAEX cocktail is described. Interference from radon and a strong influence of nitrate ion were detected in this procedure. Interference from radium, thorium and polonium emissions were very low when optimal operating conditions were reached. Quenching effects were considered and the minimum detectable activity was evaluated for different sample volumes. Isotopic analysis of samples can be performed using the proposed method. Comparisons with the results obtained with the general procedure used in alpha spectrometry with passivated implanted planar silicon detectors showed good agreement. The proposed procedure is thus suitable for uranium determination in water samples and can be considered as an alternative to the laborious conventional chemical preparations needed for alpha spectrometry methods using semiconductor detectors.

Nitrates↗
PubMed1997

Coupling condensation nucleation light scattering detection with capillary electrophoresis using electrospray.

An improved method for coupling capillary electrophoresis (CE) with condensation nucleation light scattering detection (CNLSD) is described. The method employs an electrospray aerosol source followed by aerosol particle neutralization within a weak plasma established by a polonium-210 alpha emitter. Sensitive, universal detection of underivatized proteins, peptides, and amino acids is demonstrated. The system performance was significantly affected by the operational mode of the electrospray source, characterized by the physical appearance of the droplet at the end of the electrospray capillary. With a so-called pulsating mode, relatively low backgrounds were obtained with 10 mM ammonium acetate or 10 mM ammonium acetate/10 mM ammonia CE buffers using one diffusion screen, allowing detection of proteins at single microgram per milliliter levels and amino acids and peptides at submicrogram per milliliter levels. Linearity of response, expressed as peak height or peak area; mass limits of detection (LODs) for proteins, peptides, and amino acids at the picogram level, corresponding to femtomole levels of peptides and amino acids or subfemtomole levels of proteins; and better detectability compared to UV absorbance at 214 and 200 nm were demonstrated. The separation efficiencies obtained with the CE-electrospray-CNLSD system are much higher than those obtained for a previously reported pneumatic nebulizer-based system and in the range of approximately 20,000-160,000 plates/m using the pulsating electrospray mode. With careful adjustment of the electrospray voltage, a different operating mode, called the silver bullet mode, could be established for which higher signals, lower background and background noise, and higher separation efficiencies were observed compared to the pulsating mode. The lower background levels observed with the silver bullet mode eliminated the need for the use of a diffusion screen for background control with the buffer employed. With the silver bullet mode without a diffusion screen, linear response and LODs at the 15 ng/mL level, corresponding to subpicogram or 1-2 fmol levels of underivatized peptides and amino acids, and plate numbers in the range of 65,000-220,000 plates/m were estimated.

Amino Acids↗
PubMed2001

Measurement of 224Ra and 225Ra activities in natural waters using a radon-in-air monitor.

We report a simple new technique for measuring low-level radium isotopes (224Ra and 226Ra) in natural waters. The radium present in natural waters is first preconcentrated onto MnO2-coated acrylic fiber (Mn fiber) in a column mode. The radon produced from the adsorbed radium is then circulated through a closed air-loop connected to a commercial radon-in-air monitor. The monitor counts alpha decays of radon daughters (polonium isotopes) which are electrostatically collected onto a silicon semiconductor detector. Count data are collected in energy-specific windows, which eliminate interference and maintain very low backgrounds. Radium-224 is measured immediately after sampling via 220Rn (216Po), and 226Ra is measured via 222Rn 218Po) after a few days of ingrowth of 222Rn. This technique is rapid, simple, and accurate for measurements of low-level 224Ra and 226Ra activities without requiring any wet chemistry. Rapid measurements of short-lived 222Rn and 224Ra, along with long-lived 226Ra, may thus be made in natural waters using a single portable system for environmental monitoring of radioactivity as well as tracing of various geochemical and geophysical processes. The technique could be especially useful for the on-site rapid determination of 224Ra which has recently been found to occur at elevated activities in some groundwater wells.

Environmental Monitoring↗
PubMed2002

Open-framework cadmium succinates of different dimensionalities.

Open-framework cadmium succinates, [CN(3)H(6)](2)[Cd(2)(C(4)H(4)O(4))(Cl)(2)], I; [CN(3)H(6)](2)[Cd(C(4)H(4)O(4))(2)], II; Cd(2)(C(4)H(4)O(4))(2)(C(4)N(2)H(8))(H(2)O)(3), III; [C(4)N(2)H(12)][Cd(2)(C(4)H(4)O(4))(3)].4H(2)O, IV; Cd(C(4)H(4)O(4))(H(2)O)(2), V; and Cd(3)(C(4)H(4)O(4))(2)(OH)(2)], VI, of different dimensionalities have been synthesized by hydrothermal procedure by employing two different strategies, one involving the reaction of Cd salts with organic-amine succinates and the other involving the hydrothermal reaction of Cd salts with a mixture of succinic acid and the organic amine. While the latter procedure yields structures without any amine in them, the former gives rise to amine templated cadmium succinates with open architectures. By employing guanidinium succinate we have obtained I and II, and with piperazinium succinate we obtained III and IV. Of these I has a one-dimensional chain structure, IV has a layered structure, and II and III have three-dimensional architectures. The two cadmium succinates without incorporation of amine, V and VI, possess layered and three-dimensional structures, respectively. The three-dimensional structures II and III exhibit interpenetration similar to that in diamondoid and alpha-polonium type structures, respectively.

Journal Article↗
PubMed2003

Structural analyses and magnetic properties of 3D coordination polymeric networks of nickel(II) maleate and manganese(II) adipate with the flexible 1,2-bis(4-pyridyl)ethane ligand.

Two novel inorganic-organic hybrid 3D extended networks of Ni(II) and Mn(II) having molecular formulas [(maleate)(2)Ni(3)(bpe)(4)(H(2)O)(4)](NO(3))(2).H(2)O (1) and [(adipate)Mn(bpe)] (2) (bpe = 1, 2-bis(4-pyridyl)ethane), respectively, have been synthesized and characterized by single-crystal X-ray diffraction studies and low-temperature (300-2 K) magnetic measurements. Compound 1 crystallizes in the monoclinic system, space group C2/c (No. 15), with chemical formula C(56)H(62)N(10)Ni(3)O(19), a = 30.955(4) A, b = 12.705(3) A, c = 17.058(5) A, beta = 117.26(2) degrees, and Z = 4. Compound 2 crystallizes in the triclinic system, space group Ponemacr; (No. 2), with chemical formula C(18)H(20)MnN(2)O(4), a = 8.492(2) A, b = 9.444(2) A, c = 11.533(3) A, alpha = 97.19(1) degrees, beta = 94.64(1) degrees, gamma = 105.02(1) degrees, and Z = 2. The structure determination reveals for both a 3D network. Compound 1 contains two crystallographically independent Ni(II) ions in different octahedral environments. Ni(1) lies on an inversion center, and its coordination environment comprises two chelating maleate anions and two bpe nitrogen donors, while the Ni(2) ion is surrounded by meridionally disposed three bpe N atoms, two water molecules, and one oxygen donor from the dicarboxylate anion. Of the three crystallographic independent bpe ligand, one presents an anti and the others a gauche conformation. The corresponding N-to-N distances are 9.344, 6.543, and 6.187 A. Variable-temperature magnetic susceptibility measurement of the complex reveals the existence of a dominant ferromagnetic interaction within the molecule. Compound 2 is composed of Mn(2) dimer units linked by adipate anions to form corrugated 2D sheets which, on interconnection through bpe (anti conformation, N-to-N distance of 9.391 A), produces an interpenetrated 3D alpha-polonium-related type net. Complex 2 reveals to be antiferromagnetic fitting data using a dimeric Mn(II) model that considers negligible magnetic transmission through the carbon skeleton of adipate and the bpe pathway.

Journal Article↗
PubMed2006

Helices versus zigzag chains: one-dimensional coordination polymers of Ag(I) and Bis(4-pyridyl)amine.

Five one-dimensional coordination polymers were prepared by the reaction of a bent bridging ligand, bis(4-pyridyl)amine (bpa), with an extensive series of AgX salts (X = CF3SO3, PF6, ClO4, NO3). The 1D polymer networks formed with AgCF3SO3 (1), AgPF6 (2.MeCN), and AgClO4 (3.2MeCN) all incorporated MeCN and were found to adopt a zigzag arrangement. The networks formed with AgClO4 (4) and AgNO3 (5) did not contain any solvent and adopted a single-stranded helical arrangement. Two-dimensional H-bonding networks were formed for 1 and 3.2MeCN, with network topologies 4.8(2) and (4, 4), respectively, whereas three-dimensional H-bonded networks of helices were formed for 4, showing an (8, 3)-a network topology, and 5, showing the topology of the alpha-polonium net. The three-dimensional networks both exhibited 4-fold interpenetration. The NO3- anion in 5 appeared to be acting as a template for the 3D structure.

Journal Article↗
PubMed1998

Cancer mortality in relation to monitoring for radionuclide exposure in three UK nuclear industry workforces.

Cancer mortality in 40,761 employees of three UK nuclear industry facilities who had been monitored for external radiation exposure was examined according to whether they had also been monitored for possible internal exposure to tritium, plutonium or other radionuclides (uranium, polonium, actinium or other unspecified). Death rates from cancer were compared both with national rates and with rates in radiation workers not monitored for exposure to any radionuclides. Among workers monitored for tritium exposure, overall cancer mortality was significantly below national rates [standardized mortality ratio (SMR) = 83, 165 deaths; 2P = 0.02] and none of the cancer-specific death rates was significantly above either the national average or rates in non-monitored workers. Although the overall death rate from cancer in workers monitored for plutonium exposure was also significantly low relative to national rates (SMR = 89, 581 deaths; 2P = 0.005), mortality from pleural cancer was significantly raised (SMR = 357, nine deaths; 2P = 0.002); none of the rates differed significantly from those of non-monitored workers. Workers monitored for radionuclides other than tritium or plutonium also had a death rate from all cancers combined that was below the national average (SMR = 86, 418 deaths; 2P = 0.002) but prostatic cancer mortality was raised both in relation to death rates in the general population (SMR = 153, 37 deaths; 2P = 0.02) and to death rates in radiation workers who had not been monitored for exposure to any radionuclide [rate ratio (RR) = 1.65; 2P = 0.03]. Mortality from cancer of the lung was also significantly increased in workers monitored for other radionuclides compared with those of radiation workers not monitored for exposure to radionuclides (RR = 1.31, 164 deaths; 2P = 0.01). For cancers of the lung, prostate and all cancers combined, death rates in monitored workers were examined according to the timing and duration of monitoring for radionuclide exposure, with rates of radiation workers not monitored for any radionuclide forming the comparison group. In tritium-monitored workers, RRs for prostatic cancer varied significantly according to the number of years in which they were monitored (2P = 0.03). In workers monitored for plutonium exposure, RRs for all cancers combined increased with the number of years in which they were monitored (2P = 0.04) and with the number of years since first monitoring (2P = 0.0003). There was little suggestion of systematic variation in RRs for workers monitored for other radionuclides in relation to the timing or duration of monitoring, nor did it appear that their raised rates of cancer of the lung and prostate were explained by external radiation dose. These analyses of cancer mortality in relation to monitoring for radionuclide exposure reported in a large cohort of nuclear industry workers suggest that certain patterns of monitoring for some radionuclides may be associated with higher death rates from cancers of the lung, pleura, prostate and all cancers combined. Some of these findings may be due to chance. Moreover, because of the paucity of related data and lack of information about other possible exposures, such as whether plutonium workers are more likely to be exposed to asbestos, firm conclusions cannot be drawn at this stage. Further investigations of the relationship between radionuclide exposure and cancer in nuclear industry workers are needed.

Adolescent↗
PubMed2004

Hybrid materials containing organometallic cations and 3-D anionic metal dicyanamide networks of type [Cp*2M][M'(dca)3].

A new series of hybrid materials of type [Cp*2M][M'(dca)3] has been prepared by cation templation and structurally characterised (M = Fe(III), Co(III); M'= Mn(II), Fe(II), Co(II), Ni(II), Cd(II); dca-= N(CN)2-). The crystallographic analysis of [Cp*2Fe][Cd(dca)(3)] showed that the [Cd(dca)3]- anionic framework is of a symmetrical 3-D alpha-polonium type, containing octahedral Cd nodes and micro (1,5)-dca bridging ligands. The [Cp*2Fe]+ cations occupy the cube-like cavities within the framework. The cationic and anionic-framework sublattices remain magnetically independent and display susceptibilities, over the range 300 to 2 K, of a Curie-Weiss nature obtained by adding a S= 1/2 (Cp*2Fe+) or a S= 0 (Cp*2Co+) contribution to those of the weakly antiferromagnetically coupled frameworks of M'. These hybrid species do not show any intrinsic long-range magnetic order. The present [Cp*2Fe]M'(dca)3] series display the characteristic, unusually shaped [Cp*2Fe]+ Mossbauer line, in the range 295-5 K, assigned (below 101 K) as the sum of a narrow and a broad line. Relaxation effects were evident. The [Fe(dca)3]- compound showed superimposed low-spin Fe(III) and high-spin Fe(II) lines, the latter giving relaxation broadening effects.

Journal Article↗
PubMedDate not supplied

An autoradiographic search for radioactive particles in the lungs of cigarette smokers.

Mucosal samples from the bifuracation of a major bronchus were examined from 23 patients undergoing diagnostic bronchoscopy. Samples were autoradiographed using a technique that avoids any contact between tissue and reagents until the end of autoradiographic exposure. The autoradiographs were scanned for a-particle tracks. No significant level of alpha -activity was detected, even in samples from heavy smokers who had continued to smoke within several hours of the bronchoscopy. The lower limit of detection of a-activity in this experiment was equivalent to about 55.5 becquerrels/kg (1,500 pCi/kg) Polonium-210. These results do not support the hypothesis presented by others that a radioactivity in particulate material of cigarette smoke contributes significantly to the association between cigarette-smoking and bronchial carcinoma.

Adult↗
PubMed1984

An assessment of the radiological impact of the Windscale reactor fire, October 1957.

On the 10th and 11 October 1957 a fire in the No 1 Pile at the Windscale establishment in Cumbria led to an uncontrolled release of activity to the atmosphere. The resultant cloud subsequently dispersed and radionuclides could be detected over England, Wales and parts of northern Europe. The extensive environmental measurements which were made during and after the release enabled a fairly accurate estimate to be made of the radiation doses to the most exposed individuals in the local population. Until recently, no estimates of the population dose resulting from the release had been published. This paper describes assessments which have been made by the NRPB of the population or collective dose from the release and of the possible associated health impact. In addition to the fission products that escaped, radionuclides were released from materials undergoing irradiation in the pile at the time of the fire. The assessment has included the results of a review of previously unpublished data which established the quantity of these nuclides released and considers their impact on both individual and population doses. The collective effective dose equivalent commitment from the release is estimated to have been 2.0 x 10(3) man Sv. The route of exposure which contributed the most to the collective dose was the inhalation pathway. Iodine-131 was the most important radionuclide, contributing nearly all of the collective dose to the thyroid and a large part of the collective effective dose. Polonium-210 and caesium-137 also made significant contributions; that from caesium-137 came in the longer term via external irradiation from ground deposits and the ingestion of contaminated foodstuffs. The methodology used in the study has been validated to a certain degree by comparing the predicted levels of individual thyroid activity and those measured directly in the weeks following the accident in London, Leeds and Cumbria.

Adult↗
PubMed1997

Radiation-induced transformation of SV40-immortalized human thyroid epithelial cells by single exposure to plutonium alpha-particles in vitro.

Human thyroid carcinomas have been induced following exposure of SV40-immortalized human thyroid epithelial cells in vitro to single doses (0.14 Gy to 1.57 Gy) of 3.26 MeV alpha-particles from a plutonium 238 source. Tumours were detected between 50 and 160 days following subcutaneous transplantation of the irradiated cells in athymic mice. No tumours were observed following transplantation of unirradiated cells. The relative biological effectiveness (RBE) of the alpha-particles, estimated from cell survival curves, was 4.8 at 50% survival and 3.3 at 5% survival. A first estimate of the RBE at peak tumour induction was 3.8. This system provides a means of studying the mechanisms of tumourigenesis in human thyroid epithelial cells induced by ionizing radiations, including tumours induced by single alpha particles such as from environmental natural radon and polonium and artificial plutonium and americium, and those induced by beta- or Auger-emissions from particular iodine isotopes.

Alpha Particles↗
PubMed2003

Infant doses from the transfer of radionuclides in mothers' milk.

Assessments of potential internal exposures of the child following radionuclide intakes by the mother require consideration of transfers during lactation as well as during pregnancy. Current ICRP work on internal dosimetry includes the estimation of radiation doses to newborn infants from radionuclides ingested in mothers' milk. Infant doses will be calculated for maternal intakes by ingestion or inhalation of the radionuclides, radioisotopes of 31 elements, for which fetal dose coefficients have been published. In this paper, modelling approaches are examined, concentrating on models developed for iodine, caesium, polonium, alkaline earth elements and the actinides. Comparisons of model predictions show maximum overall transfer to milk following maternal ingestion during lactation of about 30% of ingested activity for 131I, 20% for 45Ca and 137Cs, 10% for 90Sr, 1% for 210Po and low values of less than 0.01% for 239Pu and 241Am. The corresponding infant doses from milk consumption are estimated in preliminary calculations to be about two to three times the adult dose for 45Ca and 131I, 70-80% of the adult dose for 90Sr, about 40% for 137Cs, 20% for 210Po, and <0.1% for 239Pu and 241Am. Infant doses from radionuclides in breast milk are compared with doses to the offspring resulting from in utero exposures during pregnancy.

Administration, Oral↗
PubMed2006

Testing the stand-alone microbeam at Columbia University.

The stand-alone microbeam at Columbia University presents a novel approach to biological microbeam irradiation studies. Foregoing a conventional accelerator as a source of energetic ions, a small, high-specific-activity, alpha emitter is used. Alpha particles emitted from this source are focused using a compound magnetic lens consisting of 24 permanent magnets arranged in two quadrupole triplets. Using a 'home made' 6.5 mCi polonium source, a 1 alpha particle s(-1), 10 microm diameter microbeam can, in principle, be realised. As the alpha source energy is constant, once the microbeam has been set up, no further adjustments are necessary apart from a periodic replacement of the source. The use of permanent magnets eliminates the need for bulky power supplies and cooling systems required by other types of ion lenses and greatly simplifies operation. It also makes the microbeam simple and cheap enough to be realised in any large lab. The Microbeam design as well as first tests of its performance, using an accelerator-based beam are presented here.

Cell Culture Techniques↗