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PubMed2001

Classification of hot particles from the Chernobyl accident and nuclear weapons detonations by non-destructive methods.

Both after the Chernobyl accident and nuclear weapon detonations, agglomerates of radioactive material, so-called hot particles, were released or formed which show a behaviour in the environment quite different from the activity released in gaseous or aerosol form. The differences in their characteristic properties, in the radionuclide composition and the uranium and actinide contents are described in detail for these particles. While nuclear bomb hot particles (both from fission and fusion bombs) incorporate well detectable trace amounts of 60Co and 152Eu, these radionuclides are absent in Chernobyl hot particles. In contrast, Chernobyl hot particles contain 125Sb and 144Ce which are absent in atomic bomb HPs. Obvious differences are also observable between fusion and fission bombs' hot particles (significant differences in 152Eu/l55Eu, 154Eu/155Eu and 238Pu/239Pu ratios) which facilitate the identification of HPs of unknown provensence. The ratio of 239Pu/240Pu in Chernobyl hot particles could be determined by a non-destructive method at 1:1.5. A non-destructive method to determine the content of non-radioactive elements by Kalpha-emission measurements was developed by which inactive Zr, Nb, Fe and Ni could be verified in the particles.

Environmental Monitoring↗

PubMed2004

Dose effect for Japanese due to 232Th and 238U in imported drinking water.

The consumption rate of bottled mineral water in Japan has increased due to changes in eating habits and contamination of water sources. Radioactivity levels of 238U and 232Th in imported mineral water were checked from the viewpoint of internal radiation for Japanese subjects. Concentration ranges of 238U and 232Th in imported bottled mineral water, domestic bottled mineral water, domestic tap water, and domestic soft drinks were as follows: for U, N.D to 7.48 x 10(3), 1.07 to 344, 0.66 to 104, and 3.04 to 46.2 ng dm (ppt); for Th, 0.60 to 5.12, 0.65 to 22.4, 0.64 to 22.1, and 11.0 to 48.5 ng dm, respectively. In some brands of imported bottled mineral water, U concentration was sometimes much higher than domestic bottled mineral water and domestic tap water. The annual effective dose (1.5 x 10(-3) mSv y(-1) estimated from intake of 238U was approximately 7 times higher than that through dietary intake in Japanese. However, the internal dose added by drinking the imported portable water is negligible compared with total annual internal dose. Concentrations of non-radioactive elements were also compared between imported and domestic bottled water. Geometric means of cobalt, arsenic, strontium, cesium, phosphorous, and calcium in imported bottled water were higher compared with those of domestic bottled mineral water and domestic tap water. Maximum values of 11 elements (arsenic, rubidium, strontium, cesium, barium, sodium, magnesium, potassium, calcium, and manganese) were also found in imported bottled water.

Administration, Oral↗

PubMed1990

Radithor and the era of mild radium therapy.

Soon after the discovery of radium, a school of practitioners arose who were interested primarily in the physiological rather than the tumoricidal powers of this new radioactive element. This treatment philosophy was called "mild radium therapy" and involved the oral or parenteral administration of microgram quantities of radium and its daughter isotopes, often as cures for rheumatic diseases, hypertension, and metabolic disorders. Manufacturers of patent medicines responded to this market by producing a variety of over-the-counter radioactive preparations including pills, elixirs, and salves. One such nostrum was Radithor, a popular and expensive mixture of radium 226 and radium 228 in distilled water. Radithor was advertised as an effective treatment for over 150 "endocrinologic" diseases, especially lassitude and sexual impotence. Over 400,000 bottles, each containing over 2 muCi (74 kBq) of radium, were apparently marketed and sold worldwide between 1925 and 1930. The death of the Pittsburgh millionaire sportsman Eben M. Byers, who was an avid Radithor user, by radium poisoning in 1932 brought an end to this era and prompted the development of regulatory controls for all radiopharmaceuticals.

Alpha Particles↗

PubMed2005

[Amalgam risk assessment with coverage of references up to 2005].

Amalgam, which has been in use in dentistry for 150 years, consists of 50 % elemental mercury and a mixture of silver, tin, copper and zinc. Minute amounts of mercury vapour are released continuously from amalgam. Amalgam contributes substantially to human mercury load. Mercury accumulates in some organs, particularly in the brain, where it can bind to protein more tightly than other heavy metals (e. g. lead, cadmium). Therefore, the elimination half time is assumed to be up to 1 - 18 years in the brain and bones. Mercury is assumed to be one of the most toxic non-radioactive elements. There are pointers to show that mercury vapour is more neurotoxic than methyl-mercury in fish. Review of recent literature suggests that mercury from dental amalgam may lead to nephrotoxicity, neurobehavioural changes, autoimmunity, oxidative stress, autism, skin and mucosa alterations or non-specific symptoms and complaints. The development of Alzheimer's disease or multiple sclerosis has also been linked to low-dose mercury exposure. There may be individual genetical or acquired susceptibilities for negative effects from dental amalgam. Mercury levels in the blood, urine or other biomarkers do not reflect the mercury load in critical organs. Some studies regarding dental amalgam reveal substantial methodical flaws. Removal of dental amalgam leads to permanent improvement of various chronic complaints in a relevant number of patients in various trials. Summing up, available data suggests that dental amalgam is an unsuitable material for medical, occupational and ecological reasons.

Adult↗

PubMed2004

Trace elements in Jamaican tobacco.

The concentrations of 28 elements, in hand-made cigars, "rope" tobacco and freshly picked tobacco leaves from the parish of Manchester in central Jamaica, were compared with locally packaged and imported cigarettes and cigars. Except for chromium and vanadium, which are lower in the imported products, the elemental concentrations of all the brands sold in Jamaica are rather similar. The means for aluminium, cadmium, caesium, cerium, chromium, iron, thorium, uranium, vanadium and zinc for the Manchester material exceed the maximum values of the other tobaccos. The significant concentrations of heavy metals, and especially cadmium, which is about 50 times that of commercial cigarettes, reflect the known high concentrations in the soils in the region. This tobacco is not filtered and the smoke contains 50% of the cadmium. This, and the concentrations of radioactive elements, may indicate an additional health risk compared with commercial cigarettes. A study of three samples of marijuana indicates a similar level of risk from heavy metals.

Cannabis↗

PubMed2004

Experimental system to displace radioisotopes from upper to deeper soil layers: chemical research.

BACKGROUND: Radioisotopes are introduced into the environment following nuclear power plant accidents or nuclear weapons tests. The immobility of these radioactive elements in uppermost soil layers represents a problem for human health, since they can easily be incorporated in the food chain. Preventing their assimilation by plants may be a first step towards the total recovery of contaminated areas. METHODS: The possibility of displacing radionuclides from the most superficial soil layers and their subsequent stabilisation at lower levels were investigated in laboratory trials. An experimental system reproducing the environmental conditions of contaminated areas was designed in plastic columns. A radiopolluted soil sample was treated with solutions containing ions normally used in fertilisation (NO3-, NH4+, PO4--- and K+). RESULTS: Contaminated soils treated with an acid solution of ions NO3-, PO4--- and K+, undergo a reduction of radioactivity up to 35%, after a series of washes which simulate one year's rainfall. The capacity of the deepest soil layers to immobilize the radionuclides percolated from the superficial layers was also confirmed. CONCLUSION: The migration of radionuclides towards deeper soil layers, following chemical treatments, and their subsequent stabilization reduces bioavailability in the uppermost soil horizon, preventing at the same time their transfer into the water-bearing stratum.

Accidents↗

PubMed2005

Scoping analyses of geochemical sealing of early cracks in a waste container and associated drip shield, Yucca Mountain, Nevada.

Early after final emplacement of the nuclear waste containers at the proposed Yucca Mountain, Nevada, high-level-waste repository, tiny cracks (less than 200 microm wide, 1 to 2 cm deep, and a few centimeters long at most) could appear in the containers and in the drip shield protecting them. Modeling calculations were performed to understand how fast those cracks could be sealed. Under dripping conditions, they are expected to be bridged with water. If cracks are located in the drip shield, any further dripping on the waste containers located underneath will be limited. If cracks are located in a container, potentially harmful radionuclides could only travel by diffusion. In addition, water-bridged cracks will be sealed through at least two processes: precipitation of calcite with minor silica following evaporative concentration of the water residing in the cracks and continuous corrosion of the crack walls. The sealing rate is calculated as the intersection of the time of emergence of the cracks, the water dripping rate, and the decreasing evaporation rate. The evaporative driving force declines as short-lived radioactive elements, having given up much of the heat affecting the repository, are progressively depleted from the waste. Depending on the crack initiation time and environmental conditions, crack sealing varies from a few tens of years to a few thousand years. Because environmental conditions in the vicinity of the cracks and at the crack scale have not been produced, a parametric method scaling drift scale conditions is used.

Calcium Carbonate↗

PubMed2006

Gamma-ray spectroscopic analysis of selected samples from Nile river sediments in upper Egypt.

Selected sedimentary samples from different locations on the east and west banks of the Nile River in Upper Egypt were analysed by natural radioactivity measurements to detect the presence of radioactive elements. From the analysis of radiations from 226Ra, 232Th and (40)K isotopes, the samples were found to contain Ra, Th and K in concentrations up to 52 +/- 7.3, 76.2 +/- 6.2 and 351.9 +/- 17.6 Bq kg(-1), respectively. The absorbed dose rate in air was found to be in the range of 9.6-84.8 nGyh(-1). The representative external hazard index values for the corresponding samples were also estimated.

Egypt↗

PubMed1987

Radioactive uranium in various Indian tobaccos and consumable products (snuff, chutta, bidi and cigarette).

Tobacco is chewed in the form of snuff and thus its radioactivity--if there is any--goes directly into the body. Besides normal smoking, tobacco is also smoked in reverse manner in the form of "chutta", an indigenously prepared cigar made from the home grown plants of Nicotinia tobacum in South East coastal towns and villages in India. The burnt residue and the radioactive element--if there is any--in the case of chutta smoking will also go directly in the body causing hazardous effects. Uranium traces were determined in commercially available samples of snuff, chutta, bidi and cigarette tobacco using radiation damage etch technique. The analysis showed that uranium levels varied from 7.4 to 19.1 ppm in snuff, 0.16 to 0.37 ppm in chutta, 0.13 to 0.23 in bidi and 0.037 to 0.12 ppm in cigarette tobacco.

Humans↗

PubMed1997

[Dietary fibers as radiation protectors].

Chernobyl accident caused incorporation of radioactive element in body of people living in this region. A search of the methods and ways for prevention of incorporation and acceleration of elimination of nuclides is very important. Concentrates of dietary fibers (CDF) were suggested for these aims. CDF were isolated from plants and they contain complex of structural carbohydrates and lignin. It was shown that CDF isolated from lemon peel, beetroot residues after wring out, grapes seeds and other plant resources have a radioprotective properties. Authors conclude that CDF can be used in human nutrition for prevention of incorporation of nuclides.

Animals↗

PubMed2007

Activity concentrations of 226Ra, 228Th, and 40K in different food crops from a high background radiation area in Bitsichi, Jos Plateau, Nigeria.

One of the three goals of the United Nations for sustainable food security is to ensure that all people have access to sufficient, nutritionally adequate, and safe food. Decades of tin mining in the Bitsichi area of the Jos Plateau, Nigeria, have left a legacy of polluted water supplies, impoverished agricultural land, and soil containing abnormally high levels of naturally occurring radioactive elements. In order to ascertain the radiological food safety of the population, different crops that constitute the major food nutritive requirements were collected directly across farmlands in the area. The activity concentrations of (226)Ra, (228)Th, and (40)K were determined in the food and soil samples using gamma-ray spectrometry. Additionally, in situ gamma dose rate measurements were performed on the farms using a pre-calibrated survey meter. The corresponding activity concentrations in the food crops ranged from below detection limit (BDL) to 684.5 Bq kg(-1) for (40)K, from BDL to 83.5 Bq kg(-1) for (226)Ra, and from BDL to 89.8 Bq kg(-1) for (228)Th. Activity concentrations of these radionuclides were found to be lower in cereals than in tubers and vegetables. As for the soil samples, activity concentrations of these radionuclides varied from BDL to 166.4 Bq kg(-1), from 10.9 to 470.6 Bq kg(-1), and from 122.7 to 2,189.5 Bq kg(-1) for (40)K, (226)Ra, and (228)Th, respectively. Average external gamma dose rates were found to vary across the farms from 0.50 +/- 0.01 to 1.47 +/- 0.04 microSv h(-1). Due to past mining activities, the soil radioactivity in the area has been modified and the concentration level of the investigated natural radionuclides in the food crops has also been enhanced. However, the values obtained suggest that the dose from intake of these radionuclides by the food crops is low and that harmful health effects are not expected.

Background Radiation↗

PubMed1994

[Discrepancies in assessment of radiological exposure level in miners related to the use of various measurement systems].

The contamination of the air with radioactive elements (radon-222 and its decay products) occurs in coal, metal ore and chemical raw materials underground mines. This causes irradiation of the miner's respiratory system with ionizing radiation. In Poland the radiation exposure level is controlled both by the ventilation services of particular mines and by the Nofer Institute of Occupational Medicine in Lodz to the order of the State Sanitary Inspection. The in-mine services collect air samples which are next examined to determine the degree of radiation contamination (environmental monitoring), whereas the Institute uses the method of representative individual dosimetry (the dosimeters are attached to the miners' helmets). The article presents discrepancies in the levels of exposure to radiation in mines, assessed by the in-mine services and the Nofer Institute of Occupational Medicine. The hazard level determined by these services is usually one or even two times lower than that determined by the Institute. The reasons for these discrepancies are discussed.

Air Pollutants, Radioactive↗

PubMed2004

Natural radioactivity and radiation exposure in the high background area at Chhatrapur beach placer deposit of Orissa, India.

A high natural background radiation area is reported for the Chhatrapur beach placer deposit of Orissa state, on the southeastern coast of India, due to the presence of radiogenic heavy minerals. The average activity concentrations of radioactive elements 232Th, 238U and 40K were measured by gamma-ray spectrometry using a HPGe detector, and found to be 2500 +/-1850, 230 +/- 140 and 120 +/- 35 Bq kg-1, respectively, for the bulk sand samples. The absorbed gamma dose rates in air due to the naturally occurring radionuclides varied from 375 to 5000 nGy h-1, with an average value of 1625 +/- 1200 nGy h-1. The external annual effective dose rate of the region ranged from 0.46 to 6.12 mSv y-1, with an average value of 1625 +/- 1200 mSv y-1. The absorbed gamma dose rate levels of Chhatrapur beach area were similar to the monazite sand-bearing high background radiation areas of southern and southwestern coastal tracts of India and other similar areas of the world. The major contributors to the enhanced level of radiation are monazite and zircon sands.

Environmental Exposure↗

PubMed2004

Removal of dissolved rhenium by sorption onto organic polymers: study of rhenium as an analogue of radioactive technetium.

Technetium (99Tc) is one of the main components of nuclear wastes. Tc characteristics can be predicted by studying rhenium (75Re), one of its chemical analogue, thus avoiding the use of a radioactive element at high concentrations. The objectives of this experimental study was to understand the sorption behavior of Re with natural organic materials in order to define the possible condition of Tc uptake in case where Tc may be transferred into surface or ground waters. As the well-defined organic sorbents we chose chitosan which contains amine -NH2 groups; poly-galacturonic acid (PGA) and poly-styrene sulfonates (PSS) which contain respectively carboxyl -COOH and sulfonate -SO3H groups. Concerning the reaction of Re with PGA or with PSS, no interaction between Re and carboxyl or sulfonate groups was found within the detection limit of this study. Re sorption on chitosan was found to be dependent on ionic strength and pH. We propose that non-specific sorption of perrhenate ion ReO4- via electrostatic interaction takes place at the protonated amine groups NH3+. The polymer-solution interface can be described by the electric diffuse double layer model combined with the Langmuir-Freundlich model. The calculation is in good agreement with our experimental results.

Adsorption↗

PubMed1996

Pediatric malignancies in Bursa, Turkey.

Turkey is among the countries affected by ionizing radiation from the Chernobyl accident of April 26, 1986. The northern part of Turkey, where the city of Bursa is located, is presumed to be more influenced by the nuclear catastrophe. The radioactive elements in the atmosphere have been examined at various intervals after May 1, 1986 and barium-140 and lanthanum-140, fission agents of uranium-235, have been found in the atmosphere. Their exact concentration could not be measured. The aim of this report is to review the pediatric malignancies diagnosed in our institution between 1986 and 1995, with a view on any significant increase in the number of these cases. The patients were divided into three groups: acute leukemia patients (101 cases), lymphomas (44 cases), and solid tumors (31 cases). All three groups showed a tendency to increase after 1986; the increase in leukemia cases between 1986 and 1995 was found to be significantly higher (p < 0.001) when compared with the years before 1986. The increase in lymphoma and solid tumor cases after 1986 was not found to be significant (p > 0.05). We cannot rule out environmental causes other than the effects of the Chernobyl accident, and we feel that more intense epidemiological studies should be carried out on this subject in other areas of Turkey.

Acute Disease↗

PubMed1997

[Radiation-induced cancers: state of the art in 1997].

Scientists now have available a large amount of data dealing with radiation-induced neoplasms. These data went back to anecdotal observations which were made in the very first years of utilization of X-rays and radioactive elements. In fact, it is essentially the strict follow-up of the Japanese populations irradiated by the Hiroshima and Nagasaki bombing which allowed a more precise evaluation of the carcinogenicity of ionizing radiations. Further refinements came from therapeutical irradiations: it is now possible to study large cohorts of patients given well-known doses in well-defined volumes and followed for more than 20 years. Last but not least, a significant increase in the incidence and mortality of thyroid cancer has been detected in children contaminated by iodine radioisotopes after the Tchernobyl accident. Recently, some data suggested the emergence of "clusters" of leukemias close to some nuclear facilities, but this question remains highly polemical, both in France and in the UK. Other questions are still waiting for a precise answer; of course, the extrapolation of our available data to very low doses delivered at very low dose rates, but also the carcinogenic risk at high doses. For these "high" doses (about 30 to 70 Gy), a competition between mutagenesis and cell killing was expected, so that these dose levels were expected to be less carcinogenic than lower (a few sieverts) doses. Actually, recent data suggest that the carcinogenic risk goes on increasing up to relatively important doses. In addition, carcinogenic factors, such as tabacco, anticancer chemotherapy and individual susceptibility, are found more and more to be closely intricated with ionizing radiation in the genesis of a given cancer. Even if a number of questions are still pending, the already available data allow specialists, both in medicine and radioprotection, to edict strict rules which can be reasonably expected to have significantly reduced the risk of radiation-induced neoplasms in most situations.

Electromagnetic Fields↗

PubMed1995

Chloramine-T in radiolabeling techniques. II. A nondestructive method for radiolabeling biomolecules by halogenation.

Chloramine-T (CAT) is commonly used in the radiolabeling of bioactive molecules by halogenation. CAT may be used either as a solution or in an immobilized form (Iodobeads) to release radioactive elemental iodine or other halogens by oxidation of their salts. CAT has a very high chlorine potential, and it causes oxidative damage to sensitive substrate molecules, such as peptides and proteins. In some cases, the substrates are completely destroyed. To reduce the chlorine potential of CAT, morpholine was mixed with CAT prior to exposure to the substrates. This formed N-chloromorpholine, in situ, which readily reacted with KI to form I2. The kinetics of the formation of N-chloromorpholine from CAT and morpholine were studied spectrophotometrically by following the disappearance of CAT at 250 nm. The reaction was found to be rapid at all pH's from 5 to 11. 1-Aminocyclohexanecarboxylic acid (a model amino acid) decomposed rapidly in the presence of CAT, but there was no decomposition in the presence of N-chloromorpholine. N-Chloromorpholine was compared to CAT solution and Iodobeads for the iodination of L-tyrosine. The formation of mono- and diiodotyrosine were followed by HPLC. On an equimolar basis (0.55 microM), N-chloromorpholine produced a much greater yield of the mono- and diiodinated tyrosine than Iodobeads. Furthermore, decomposition products were observed when tyrosine was exposed to Iodobeads for 15 min. When a CAT solution was used at a higher concentration (5.5 microM), a substantial amount of decomposition occurred, and the yields of the two iodinated species were very small.(ABSTRACT TRUNCATED AT 250 WORDS)

Chloramines↗

PubMed2001

Chloramine-T in radiolabeling techniques. IV. Penta-O-acetyl-N-chloro-N-methylglucamine as an oxidizing agent in radiolabelling techniques.

Chloramine-T (CAT) is commonly used in radiolabeling of bioactive molecules by halogenation. CAT is used to release radioactive elemental iodine by oxidation of its salts. Unfortunately, CAT is a strong oxidizing agent and can cause significant damage to peptides and proteins. This may lower the yield of the iodination reaction and may produce undesirable side products. Recently, it was found that the in situ formation of N-chlorosecondary amines, by the addition of secondary amines to CAT prior to exposure to the substrate, can reduce the oxidative damage caused by CAT. To simplify the method, we prepared penta-O-acetyl-N-chloro-N-methylglucamine (NCMGE) as a solid N-chlorosecondary amine. The chemical reactivity of NCMGE toward a model amino acid, 1-aminocyclohexane carboxylic acid, was compared with that of chloramine-T. In the presence of the model amino acid, CAT lost all its chlorine titer within 60 min while NCMGE retained 99% of its chlorine titer. NCMGE was compared to CAT for the iodination of l-tyrosine and leucine enkephalin. For both substrates, the NCMGE method produced larger or equal yields of the monoiodo and diiodo products and less decomposition. It is proposed that the method employing NCMGE to release diatomic iodine is more convenient and efficient for radiolabeling peptides and proteins than currently used methods.

Amino Acids, Cyclic↗