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PubMed1981

Biophysical investigations of the dose-effect relationship in chromosome aberrations of human lymphocytes caused by thorotrast deposits. I. Physical aspects.

Thorotrast is a X-ray contrast medium which has been used in the years 1930-1950. It is hardly ever eliminated from the body and is stored in the organs of the reticulohistiocytic system (RHS). Since Thorotrast contains all radionuclides of the thorium decay chain, the effect of internal irradiation by these radionuclides can be investigated in the so called "Thorotrast patients". It is the purpose of this study to determine the radiation dose absorbed by the lymphocytes of the peripheral blood of these persons, and to correlate it with their chromosome aberration rate. Part I of the paper describes the physical aspects of dose evaluation. The chromosome aberration rates of Thorotrast patients were subjected to a repeated statistical test. They show a logarithmic normal distribution at a mean value of about seven dicentric chromosomes per 100 cells. The corresponding dose has to be determined. The method for evaluating size and distribution of Thorotrast conglomerates in the examined tissue is demonstrated, and the function and resolution power of the applied "texture analysing system" (TAS) is described. Size-distributions of Thorotrast conglomerates of lymph nodes from the neck, the lung and from the lower aorta (bifurcatio) are given. In the lymphatic system more than 90% of the absorbed dose in tissue is due to alpha-particles. The computation method of calculating the self-absorption of alpha-particles in the conglomerates and of calculating the annual doses in the lymph nodes is described. The values lie between 135 and 1200 rad/year. The contribution to irradiation from outside the lymphatic system can be neglected. The method of dose determination is discussed and compared with microdosimetric methods. With these methods, the dose of a lymphocyte caused by one hit of an alpha-particle lies between 80 and 920 rad. An energy dissipation does not take place and the total energy emitted acts on the lymphocytes thus inducing chromosome aberrations.

Animals↗
PubMed2002

Peteosthor - a medical disaster due to Radium-224A personal recollection.

Up to the end of World War II, there was no effective therapy against bone tuberculosis, and even today there is no treatment for ankylosing spondylitis. However, in the 1940s up to about 1956, radiotherapy with "Peteosthor" - a drug containing Thorium X ((224)Ra) as an effective compound - was introduced in Germany as a presumed cure and it maintained a central place in the treatment of these diseases. In 1948, I was entrusted to assess the new treatment. Animal studies and the clinical evaluation of the patients made me soon realise a number of severe adverse health effects which induced me to pronounce and subsequently repeat warnings against the intravenous administration of high doses of (224)Ra, especially because it was then administered predominantly to children and juveniles. As a consequence, this type of treatment was finally abandoned in 1956. But there remained a need to observe and document the resulting late health effects. Already in 1967, our initial follow-up study provided data for about 800 patients with exact information on the (224)Ra dose levels administered, administration schemes, and the resulting detrimental effects. A large number of bone sarcomas was the most severe consequence, but even today there is a broad spectrum of other grave health effects. A summary of the major scientific insights which have been achieved in the course of the still on-going epidemiological studies is part of this report.

Aged↗
PubMed1990

Automated determination of fluoride using silicone-facilitated diffusion.

An automated procedure for the determination of fluoride in biological fluids that uses silicone-facilitated diffusion at room temperature to separate fluoride from other sample constituents is described. Fluoride is measured by its ability to quench the fluorescence of a morin-thorium complex. The procedure appears to be free of significant interferences and is capable of measuring fluoride in the submicromolar range.

Animals↗
PubMed1992

Frequency of mutant T lymphocytes defective in the expression of the T-cell antigen receptor gene among radiation-exposed people.

The frequency of mutant T lymphocytes defective in T-cell receptor gene (alpha or beta) expression was measured using the 2-color flow cytometric technique. Results for a total of 203 atomic bomb survivors, 78 of whom were proximally exposed (DS86 doses of greater than or equal to 1.5 Gy) and 125 of whom were distally exposed (DS86 dose of less than 0.005 Gy), showed that the mutant frequency was significantly higher in males than in females. No significant dose effects were observed. In contrast, a significant increase of mutant frequency was observed for 6 patients treated with Thorotrast, a contrast medium containing thorium-232 formerly used for radioligands. In addition, thyroid disease patients treated with 131I showed a dose-related increase of mutant frequency. It was suggested that the present T-cell receptor mutation assay has a unique characteristic as a biological dosimeter for measurement of recent exposures to genotoxic agents.

Adult↗
PubMed1984

The radioactivity content of United Kingdom coal.

Twenty samples of coal representing each of the seven major regions of the National Coal Board have been analysed for their natural radioactivity content. A variety of methods have been used to verify the results, but the major technique used was radiation spectrometry of 3 kg samples. The results indicate a mean value for uranium and radium activity in British coals of 14.5 Bq/kg, for thorium 12.5 Bq/kg and for potassium 150 Bq/kg. These are significantly lower levels of actinides than have been previously reported and represent only two thirds of those previously used as source terms for assessment of the radiological impact of fossil fuel burning in the U.K.. The content of potassium in U.K. coal is twice the accepted global mean but the radiological significance of this element is negligible. A subsidiary finding is that uranium and its daughter radium are in secular radioactive equilibrium in coal within the experimental error of the analysis.

Coal↗
PubMed1985

Dose estimates for exposure to radioactivity in gas mantles.

In this paper dose estimates are given for internal and external exposure that result, due to radioactive thorium, from the use of the incandescent mantles for gas lanterns. The collective, effective dose equivalent for all users of gas mantles is estimated to be about 100 Sv per annum in the Netherlands. For the population involved (ca. 700,000 persons) this is roughly equivalent to 5% to 10% of the collective dose equivalent associated with exposure to radiation from natural sources. The major contribution to dose estimates comes from inhalation of radium during burning of the mantles. A pessimistic approach results in individual dose estimates for inhalation of up to 0.2 mSv.

Aerosols↗
PubMed1995

Distribution of toxic and radiation components in air particulates.

The concentrations of several toxic heavy metals and volatile organic compounds (VOCs) in various types of Hungarian fly-ash fine particulates were investigated by means of instrumental neutron activation analysis, X-ray fluorescence analysis and gas chromatography, coupled with mass spectrometry. Within a power station, particulate samples were taken from the boiler zone (BO), from the electrostatic dust filter chamber (FI) and from the flue-gas at the top of the stack (ST). Enrichment rates of the toxic metals both in FI and ST particulate fractions related to the BO concentrations were calculated to enable the temperature dependence on the adsorption of the toxic components to be studied. In addition, both the total amounts of the VOCs and their partial distributions in accordance with the number of carbon atoms were also studied in fly-ash particulates. From them, 31 organic species were identified and determined. Since Hungarian brown coals have high uranium and thorium contents, the specific radioactivities of the daughter isotopes of both the 232Th and 238U decay series were also measured and are discussed.

Air Pollutants↗
PubMed1982

An electron microscopic examination for the presence of acid groups in the organic matrix of mineralization nodules in foetal bone.

Several biochemical and histochemical investigations of the role of glycosaminoglycans (GAG) in bone and cartilage mineralization have been performed, but the exact relationship between GAG and mineralization is not clear. We performed an electron microscopic histochemical study of the composition of organic bone matrix at sites of beginning mineralization in mouse foetal radii, directing special attention to the presence and location of GAG. To demonstrate these substances, use was made of positive colloidal thorium dioxide and ruthenium red. The results demonstrate the presence of material containing acid groups in the young mineralization nodules. It is concluded that part of the demonstrated acid groups might be sulphate groups of glycosaminoglycans.

Animals↗
PubMedDate not supplied

MRI in thorotrastosis.

Magnetic resonance imaging (MRI) and computed tomography (CT) were performed in four patients with thorotrastosis. On CT scan, Thorotrast (thorium oxide) deposition was shown as high-density areas in the liver and spleen and the abdominal lymph nodes. These deposits were not found on MRIs. Splenic volume was significantly small due to atrophy. The contrast-noise ratio in the spleen on T1-weighted images was significantly lower. Thorotrast deposition does not affect MRI appearance; therefore it may be useful for the early detection of malignant tumors as a complication of thorotrastosis.

Aged↗
PubMed1988

Liver tumours.

Humans are remarkably resistant to many carcinogens that readily produce liver tumours in rodents, particularly the rat. The neoplastic process has been extensively studied in animal experiments, but little is known so far of how it evolves in humans. Few drugs have been shown to cause liver tumours in humans, and the risk appears to be low. The best-known examples are C17-alkylated or ethinylated gonadal sex steroids. Oral contraceptives have now been in use by millions for thirty years, but only a few hundred cases at most of liver cell adenoma have been observed. The role of these substances in liver cell carcinoma remains controversial, and the evidence is weaker still in relation to focal nodular hyperplasia and other tumour-like conditions. Anabolic-androgenic steroids stand out as the major cause of peliosis, but liver cell tumours induced by them seem to be adenomas and not carcinomas as originally suggested. The effect that both oral contraceptives and anabolic-androgenic steroids have on liver vasculature is of great clinical importance as the most important complication of liver tumours is rupture, leading to life-threatening haemorrhage. For this reason, liver tumours arising in users of these drugs should be removed whenever feasible. Thorium dioxide will remain a risk factor for the development of angiosarcoma, liver cell carcinoma and bile duct carcinoma for some time yet, and the number of patients who have been exposed is high--tens of thousands at least. The evidence of a carcinogenic role for many other drugs is anecdotal or weak. Neoplasia in the liver seems to be the least important side-effect of drugs in clinical use.

Anabolic Agents↗
PubMed2003

Radioelement distributions in the Proterozoic granites and associated pegmatites of Gabal El Fereyid area, Southeastern Desert, Egypt.

Lithologically, the rock types in the Gabal El Fereyid area are dominantly granites with minor amounts of pegmatites. The granites range in composition from tonalite to granite-adamallite with minor acidic dikes, quartz and pegmatite veins. The granite-adamallite is peraluminous and formed as a result of partial melting of amphibole-bearing rocks at depths of approximately 24-30 km and at temperatures of 800-950 degrees C. Among the different rock types, the muscovite-rich pegmatites had the highest U and Th contents (66 and 38 ppm on average, respectively). The high level of radioactivity in pegmatites is attributed to the presence of the radioactive minerals thorianite, uranophane and allanite as confirmed by XRD analysis. Binary relations of Zr/U, Zr/Th, Ce/U and Ce/Th against either U or Th in the granite-adamellite exhibit significant negative correlations indicating that both elements are not preferentially hosted in the accessory minerals phases such as zircon and monazite, but could be associated with major forming minerals such as biotite, muscovite, plagioclase and quartz, or U is situated within labile sites within granite. The uranium and thorium enrichment in the pegmatites is a two-stage process. The primary stage is magmatic whereas the secondary enrichment is from hydrothermal concentration. The magmatic U and Th are indicated by the presence of thorianite and allanite, whereas evidence of hydrothermal mineralization is the alteration of rock-forming minerals such as feldspar and the formation of secondary minerals such as uranophane and pyrite.

Desert Climate↗
PubMed2004

Radioactivity distribution in some Permian sediments from the Iratí and Corumbataí Formations of the Paraná Basin, Southeastern Brazil.

In the city of Limeira, southeastern Brazil, an important exposure of Permian sediments of the Paraná basin was revealed by an open pit mine that exploits limestone for production of soil correction compounds and raw materials for the ceramic industry. The radioactivity of these sediments was investigated in some detail and the results provided a general view of the vertical distributions of uranium, thorium and potassium concentrations and of the element ratios U/K, U/Th and Th/K. In general, the concentrations of the main natural radioactive elements are low, with uranium being enriched in some limestone and shale levels. In addition the results showed that the 238U series is in radioactive disequilibrium in many of the analyzed samples. Although the origin of the observed disequilibrium has not been investigated, the results suggest that it is due to weathering processes and water interaction with the rock matrix.

Brazil↗
PubMed2006

Effect of soil humic and fulvic acids, pH and ionic strength on Th(IV) sorption to TiO2 nanoparticles.

Thorium is considered as a chemical analog of other tetravalent actinides. Herein, the sorption of Th(IV) on TiO(2) in the presence or absence of soil fulvic acid (FA)/humic acid (HA) as a function of pH, ionic strength and FA/HA concentration has been studied by a batch method. The morphology was characterized by scanning electron microscopy (SEM). The results indicate that sorption of Th(IV) on TiO(2) increases from 0% to approximately 94% at pH 1 approximately 4, and then maintains level with increasing pH values. Both FA and HA have a positive effect on Th(IV) sorption at low pH values and the contribution of FA on Th(IV) sorption is rather higher than that of HA at pH<4. The sorption is weakly dependent on the concentration of KNO(3) in solution, but the cations K(+), Na(+) and Li(+) influence Th(IV) sorption more obviously. The batch results indicate that the inner sphere complex formation is formed at bare surfaces or FA/HA-bound TiO(2) particle surfaces. Results of SEM analysis show that the particle sizes of TiO(2), Th-TiO(2) and Th-HA-TiO(2) colloids are quite different. Surface complexation may be considered as the main sorption mechanism.

Adsorption↗
PubMed2004

Biomagnification of 7Be, 234Th, and 228Ra in marine organisms near the northern Pacific coast of Japan.

Enrichment of natural radionuclides of thorium, radium and beryllium in several kinds of marine organisms was investigated near the Pacific coast of Miyagi Pref., Japan. The radioactivity of 7Be, 210Pb, 234Th, 238U, 228Ra and 137Cs was measured using gamma spectrometry. High concentrations of 234Th were observed in ascidian livers (50-400 Bq/kg dry) and excrement (2000-2900 Bq/kg dry), although the parent 238U concentrations were less than 3 Bq/kg dry. Such extreme disequilibrium between 238U and 234Th activity was observed in other organisms (barnacles, mussels and brown algae). Relatively high concentrations of 228Ra were detected in ascidian livers and were observed to decrease according to its half-life (5.75 year), suggesting disequilibrium with its parent 232Th. High concentrations (about 1900-5000 Bq/kg dry) of 7Be were detected in ascidian liver. Possible mechanisms for the observed biomagnification and bioaccumulation of these radionuclides in the organisms analyzed were proposed.

Animals↗
PubMed2005

Radon concentration in soil gas around local disjunctive tectonic zones in the Krakow area.

The purpose of this study was to investigate radon in the vicinity of geologic fault zones within the Krakow region of Poland, and to determine the influence of such formations on enhanced radon concentrations in soil. Radon ((222)Rn and (220)Rn) concentration measurements in soil gas (using ionization chamber AlphaGUARD PQ2000 PRO and diffusion chambers with CR-39 detectors), as well as radioactive natural isotopes of radium, thorium and potassium in soil samples (using gamma ray spectrometry with NaI(Tl) and HPGe detectors), were performed. Site selection was based on a geological map of Krakow. Geophysical methods (ground penetrating radar and shallow acoustic seismic) were applied to recognize the geological structure of the area and to locate the predicted courses of faults. Elevated levels of radon and thoron in soil gas were found in the study area when compared with those observed in an earlier survey covering Krakow agglomeration. For (222)Rn, the arithmetic mean of registered concentration values was 39 kBq/m(3) (median: 35.5 kBq/m(3)). For (220)Rn, the arithmetic mean was 10.8 kBq/m(3) and median 11.8 kBq/m(3).

Geological Phenomena↗
PubMed2004

Environmental 238U and 232Th concentration measurements in an area of high level natural background radiation at Palong, Johor, Malaysia.

Concentrations of uranium-238 and thorium-232 in soil, water, grass, moss and oil-palm fruit samples collected from an area of high background radiation were determined using neutron activation analysis (NAA). U-238 concentration in soil ranged from 4.9 mg kg(-1) (58.8 Bq kg(-1)) to 40.4 mg kg(-1) (484.8 Bq kg(-1)), Th-232 concentration ranged from 14.9 mg kg(-1) (59.6 Bq kg(-1)) to 301.0 mg kg(-1) (1204 Bq kg(-1)). The concentration of U-238 in grass samples ranged from below the detection limit to 0.076 mg kg(-1) (912 mBq kg(-1)), and Th-232 ranged from 0.008 mg kg(-1) (32 mBq kg(-1)) to 0.343 mg kg(-1) (1.372 Bq kg(-1)). U-238 content in water samples ranged from 0.33 mg kg(-1) (4.0 Bq L(-1)) to 1.40 mg kg(-1) (16.8 Bq L(-1)), and Th-232 ranged from 0.19 mg kg(-1) (0.76 Bq L(-1)) to 0.66 mg kg(-1) (2.64 Bq L(-1)). It can be said that the concentrations of environmental U-238 and Th-232 in grass and water samples in the study area are insignificant. Mosses were found to be possible bio-radiological indicators due to their high absorption of the heavy radioelements from the environment.

Bryophyta↗
PubMed2005

Measurement of natural radioactivity in building materials in Qena city, Upper Egypt.

Building materials cause direct radiation exposure because of their radium, thorium and potassium content. In this paper, samples of commonly used building materials (bricks, cement, gypsum, ceramics, marble, limestone and granite) in Qena city, Upper Egypt have been collected randomly over the city. The samples were tested for their radioactivity contents by using gamma spectroscopic measurements. The results show that the highest mean value of (226)Ra activity is 205+/-83 Bqkg(-1) measured in marble. The corresponding value of (232)Th is 118+/-14 Bqkg(-1) measured in granite. For (40)K this value is (8.7+/-3.9)x10(2) Bqkg(-1) measured in marble. The average concentrations of the three radionuclides in the different building materials are 116+/-54, 64+/-34 and (4.8+/-2.2)x10(2) Bqkg(-1) for (226)Ra, (232)Th and (40)K, respectively. Radium equivalent activities and various hazard indices were also calculated to assess the radiation hazard. The maximum mean of radium equivalent activity Ra(eq) is 436+/-199 Bqkg(-1) calculated in marble. The highest radioactivity level and dose rate in air from these materials were calculated in marble.

Cities↗
PubMed2006

234U and 230Th determination by FIA-ICP-MS and application to uranium-series disequilibrium in marine samples.

A 234U and 230Th determination method based on an extraction chromatographic separation on a flow injection system coupled to a quadruple ICP-MS was developed. Two-milliliter UTEVA (Eichrom Co.) cartridges were applied as separation tool and 236U and 229Th as spikes. Loading and washing steps were carried out in 3 M HNO3 solution and 0.05 M ammonium oxalate applied to elute both uranium and thorium. The method was applied initially to the IAEA-327 soil reference sample and NIST SRM 4357 ocean sediment reference material, with the obtained 234U and 230Th concentrations in agreement with the reference levels. Samples from a deep-sea sediment core (2450 m water depth) were analyzed and based on 230Th/234U dating, a mean sedimentation rate of 3.3 cm ky(-1) was calculated. Samples from two sediment layers were also dated by 14C-AMS and the observed ages agree with the 230Th/234U results.

Geologic Sediments↗