Health effects of exposure to radon: implications of the radon bed mattress incident in Korea / 한국역학회지

Radon is a naturally occurring radioactive material formed by the slow decay of uranium and thorium found in the earth's crust or construction materials. Internal exposure to radon accounts for about half of the natural background radiation dose to which humans are exposed annually. Radon is a carcinogen and is the second leading cause of lung cancer following smoking. An association between radon and lung cancer has been consistently reported in epidemiological studies on mine workers and the general population with indoor radon exposure. However, associations have not been clearly established between radon and other diseases, such as leukemia and thyroid cancer. Radiation doses are assessed by applying specific dose conversion coefficients according to the source (e.g., radon or thoron) and form of exposure (e.g., internal or external). However, regardless of the source or form of exposure, the effects of a given estimated dose on human health are identical, assuming that individuals have the same sensitivity to radiation. Recently, radiation exceeding the annual dose limit of the general population (1 mSv/yr) was detected in bed mattresses produced by D company due to the use of a monazite-based anion powder containing uranium and thorium. This has sparked concerns about the health hazards for mattress users caused by radiation exposure. In light of this event, this study presents scientific information about the assessment of radon and thoron exposure and its human implications for human health, which have emerged as a recent topic of interest and debate in society.

Health Effects of Radon Exposure

Radon is a naturally occurring radioactive material that is formed as the decay product of uranium and thorium, and is estimated to contribute to approximately half of the average annual natural background radiation. When inhaled, it damages the lungs during radioactive decay and affects the human body. Through many epidemiological studies regarding occupational exposure among miners and residential exposure among the general population, radon has been scientifically proven to cause lung cancer, and radon exposure is the second most common cause of lung cancer after cigarette smoking. However, it is unclear whether radon exposure causes diseases other than lung cancer. Media reports have often dealt with radon exposure in relation to health problems, although public attention has been limited to a one-off period. However, recently in Korea, social interest and concern about radon exposure and its health effects have increased greatly due to mass media reports of high concentrations of radon being released from various close-to-life products, such as mattresses and beauty masks. Accordingly, this review article is intended to provide comprehensive scientific information regarding the health effects of radon exposure.

Health effects of exposure to radon: implications of the radon bed mattress incident in Korea / 한국역학회지

Radon is a naturally occurring radioactive material formed by the slow decay of uranium and thorium found in the earth's crust or construction materials. Internal exposure to radon accounts for about half of the natural background radiation dose to which humans are exposed annually. Radon is a carcinogen and is the second leading cause of lung cancer following smoking. An association between radon and lung cancer has been consistently reported in epidemiological studies on mine workers and the general population with indoor radon exposure. However, associations have not been clearly established between radon and other diseases, such as leukemia and thyroid cancer. Radiation doses are assessed by applying specific dose conversion coefficients according to the source (e.g., radon or thoron) and form of exposure (e.g., internal or external). However, regardless of the source or form of exposure, the effects of a given estimated dose on human health are identical, assuming that individuals have the same sensitivity to radiation. Recently, radiation exceeding the annual dose limit of the general population (1 mSv/yr) was detected in bed mattresses produced by D company due to the use of a monazite-based anion powder containing uranium and thorium. This has sparked concerns about the health hazards for mattress users caused by radiation exposure. In light of this event, this study presents scientific information about the assessment of radon and thoron exposure and its human implications for human health, which have emerged as a recent topic of interest and debate in society.

Assessment of dose due to natural radio-nuclides in vegetables of high background radiation area in south-eastern part of Bangladesh

The aims of the study are to determine the radioactivity concentrations of [226]Ra, [238]U, [232]Th and [40]K in vegetables of a recently found high background radiation area of south-eastern part of Bangladesh and to detect the radiological risks to human from intake of these vegetables. 10 plant samples were collected randomly from different locations of the study area. The radio-nuclides in papaya were measured by direct gamma-ray spectrometry using HPGe detector. The average activity concentrations of [226]Ra, [238]U, 232Th and [40]K in papaya samples were 80.95 +/- 13.61, 64.77 +/- 38.47, 83.53 +/- 20.50 and 1691.45 +/- 244.98 Bq kg[-1] respectively. The annual effective ingestion dose due to intake of papaya was 1.1 mSv Y[-1]. The concentrations of radio-nuclides in the papaya samples found in present study were higher than the world average values suggested by the UNSCEAR. The annual effective ingestion dose was found 3.8 times higher than total exposure per person resulting from the ingestion of terrestrial radioisotopes

Measurement of [226]Ra, [232]Th, [137]Cs and [40]K activities of wheat and corn products in Ilam province - Iran and resultant annual ingestion radiation dose

Natural background radiation is the main source of human exposure to radioactive material. Soils naturally have radioactive mineral contents. The aim of this study is to determine natural [[238] U, [232] Th, [40] K] and artificial [[137] Cs] radioactivity levels in wheat and corn fields of Eilam province. HPGe detector was used to measure the concentration activity of [238]U and [232]Th, [40] K and [137] Cs in wheat and corn samples taken from different regions of Eilam province, in Iran. In wheat and corn samples, the average activity concentrations of [226] Ra, [232] Th, [40]K and [137] Cs were found to be 1,67, 0.5, 91.73, 0.01 and 0.81, 0.85, 101.52, 0.07Bp/ kg [dry weight], respectively. H[ex] and H[in] in the present work are lower than 1. The average value of H[ex] was found to be 0.02 and 0.025 and average value of H[in] to be found 0.025 and 0.027 in wheat fields samples and corn samples in Eilam provinces, respectively. The obtained values of AGDE are 30.49 mSv/ yr for wheat filed samples and 37.89 mSv/ yr for corn samples; the AEDE rate values are 5.28 mSv/yr in wheat filed samples and this average value was found to be 6.13 mSv/yr in corn samples in Eilam. Transfer factors [TFs] of long lived radionuclide such as [137]Cs, [226]Ra, [232] Th and [40]K from soils to corn and wheat plants have been studied by radiotracer experiments. The natural radioactivity levels in Eilam province are not at the range of high risk of morbidity and are under international standards

Activity concentrations of [232]Th, [226]Ra and [40]K and gamma radiation absorbed dose rate levels in farm soil for the production of different brands of cigarette tobacco smoked in Nigeria

Presently, the British-American Tobacco Company [BAT] located in Ibadan, Oyo State is the only tobacco producing company in Nigeria accounting for about nine different brands of cigarette tobacco smoked in the country. The tobacco leaves are produced from some farmlands located in Oke-Ogun area of Ibadan where special fertilizers are used for the growing of the tobacco leaves. The use of this fertilizer may enhance natural radionuclide contents in the farm soils and through root uptake be accumulated in the leaves. In this study, soil samples from three farmlands used for the production of the tobacco leaves were collected in order to determine the activity concentrations of [226]Ra, [232]Th and [40]K in the farm soil. Measurements for the determination of the activity concentrations were carried out using gamma-ray spectrometry comprising a lead-shielded 76 mm _ 76 mm NaI[Tl] detector crystal [Model 802 series, Bicron Nal] coupled to a Canberra series 10 plus multichannel analyzer [MCA] [model 1104] through an preamplifier base. Results of measurements showed that the average activity concentrations of the natural radionuclides in the soil samples across the three farms varied from 2550.4 +/- 154.6 to 3208.9 +/- 188.7 Bq kg[-1] for [40]K, 33.1 +/- 11.9 to 39.9 +/- 9.3 Bq kg[-1] for [226]Ra, while for [232]Th it varied between 51.98 +/- 8.4 and 56.08 +/- 17.51 Bq kg[-1]. The activity concentrations of these radionuclides and gamma absorbed dose rates due to the concentration of these radionuclides were found to be higher than world average values while those of the control farm values were lower to world averages and the tobacco leaf farms. From the results obtained the fertilizer type used on the farmlands for the tobacco leaf production was very rich in [40]K with typical values greater 2000 Bq kg-[1]. Also there may be possible high signatures of [210]Pb and [210]Po in the tobacco leaves and the cigarette samples smoked in the country. This is a subject for future research consideration given the fact that alpha radiation plays a major role in the etiology of lung cancer

Studying the natural radioactivity in some tobacco cigarettes imported to Iraq from unknown origins

Natural radioactivity isotope in ten tobacco leaf samples presented in different cigarettes imported to Iraq from unknown origins, were determined by gamma-ray spectrophotometer. The study revealed several naturally occurring radionuclides in these samples. Such isotopes were "Bi-214" which belongs to U-238 series and; "Pb-212, Bi-212, Ac-228" which belongs to Th-232 series, and K-40. Furthermore, the results show that the maximum concentrations of Pb-212, Bi-214, Bi-212, Ac-228 and K-40 radionuclides were [9.13, 59.08, 17.15, 3.1 and 102.61 Bq/Kg]. Such radioactive isotopes were respectively detected in Bisnuse club, Grip, again Bisnuse club, Najema and pin cigarette type. It is concluded from the results that Iraqi cigarettes are heavily contaminated with several radioactive isotopes. This may be reflected as a major health impact among Iraqi populations

improved method for leaching of thorium in monazite using sodium hydroxide

The leaching of monazite with sodium hydroxide has been attempted. Factors such as time of leaching, concentration of sodium hydroxide sclution and temperature were tested with the hope to optimize the leaching efficiency. XRF technique was used in the determination of concentration. In this work Egyptian monastic leached by alkaline treatment in reflux instead of the pyrometallurgical process using mechanochemical treatment where grinding is carried out in the presence of sodium hydroxide and followed by pressure leaching in autoclave that gives an incongruent result. It has been found that the monazite was effectively decomposed in 2hr at - 130°C using 600g/1 sodium hydroxide in the reflux. The recovery of thorium by this method and under these conditions is about 98.1%. A mathematical formula is also deduced which enables the calculation of thorium concentration in ppm obtained from the leaching in reflux system under different conditions with a good agreement with the experimental values and that obtained from the XRF technique

survey on stimulatory effects of topical application of radioactive lantern mantle powder on wound healing

Poorly educated people in some parts of Iran use burned mantles as a wound healing medicine. To perform surface area measurement, twenty rats were divided randomly into two groups of 10 animals each. The first group received topical burned radioactive lantern mantle powder on the first to third days after making excision wounds. The second group received non-radioactive lantern mantle powder. For histological study, 36 male rats were randomly divided into two groups of 18 animals each. Full thickness excision wound [314 +/- 31.4 mm[2]] was made on the dorsal neck in all animals after inducing general anesthesia. For the first three days, cases had received topical application of the radioactive lantern mantle powder. Finally, to measure the tensile strength, an incision was made on the dorsal neck of the rats. Surface area measurement of the wounds showed a progressive surface reduction in both groups. Histological study showed a significant statistically difference between cases and controls with respect to fibrinoid necrosis and neutrophilic exudate on days 3 and 14. Considering the existence of granulated tissue, a significant difference was observed between case and control groups on days 3 and 7. Tensile strength study showed no significant difference between the cases and controls. Topical use of radioactive mantle powder can accelerate the healing process of the wound in rats

A 20-year follow-up study on the effects of long-term exposure to thorium dust / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>To investigate the possible effects of long-term exposure to dust containing thorium and thoron progeny on dust-exposed miners.</p><p><b>METHODS</b>A negative, high voltage, exhaled thoron progeny measurement system was used to estimate the miners' thorium lung burden.</p><p><b>RESULTS</b>The highest thorium lung burden of 638 miners was 11.11 Bq. The incidence of stage 0(+) pneumoconiosis was higher among dust-exposed miners. Lung cancer mortality of the dust-exposed miners was significantly higher than that of controls (P < 0.005).</p><p><b>CONCLUSION</b>There is a difference in cancer rates between those who have long-term exposure to dust containing thorium (in which carcinogenic ThO(2) and SiO(2) exist) and thoron progeny and those who have not.</p>

Isatin isonicotinoyl hydrazone complexes of tervalent metals Ti, Zr, Sn, Pt, and Th

Two forms of isatin isonicotinoyl hydrazone have been prepared. Analytical, t.g.a., electronic, i.r. and n.m.r. results show that the orange form [H.G.] is the anti-tautomer hydrazone whereas the yellow form [H.Y]. 1/2H[2]O is a mixture of imide-imidol of the syn one stabilized by H-bond through H-chelates. The complexes of Ti, Zr, Sn, Pt and Th with HG and HY were prepared and characterized using a variety of analytical, spectral and thermal measurements. The analytical data showed that 1:1 or 1:2 molar compounds were obtained. The title hydrazone behaved as a neutral or monobasic bidentate ligand coordinating through the azomethine N and isatin O or eventually as tridentate coordinating through O, N and pyridine N

Chelation behaviour of some lanthanide [III], scandium [III], yttrium [III], thorium [IV] and uranium [VI] complexes with some hydroxy nitrosocoumarins

The stability constants of the lanthanide ions [La, Ce, Pr, Nd, Sm, Gd, Dy, Er and Yb]; Sc, Y, Th and UO22+ ions with some hydroxy nitrosocoumarins were determined in 40% ethanol-water mixture at 25 degree and 0.1 ionic strength. It was found that the stability constants of the complexes increased with increasing ionic radii, from Y to Sm. The so called Gadolinium break was observed with heavier lanthanides. Sc and Th complexes possessed the highest stability constants. The potentiometric measurements and conductimetric titrations showed that 1: 1 and 1: 2 [M: L] complexes were invariably formed

Cerium [III], thorium [IV] and dioxo-uranium [VI] complexes of 6,7-dihydroxy-4methyl-coumarin: acid dissociation constants in ethanol-water mixtures

The successive stability constants of Ce [III], Th [IV] and UO2, [VI] chelates with 6,7-dihydroxy-4-methylcoumarin have been determined pH- metrically at different temperatures and ionic strengths in 60% [by volume] ethanol-water mixture. A 1: 1 and 1: 2 complexes are formed and evidenced by conductometric studies. The thermodynamic parameters for these chelates have been determined. Smaller values of delta H show the predominance of the entropy effect in the formation of these chelates. The structure of the solid complexes of UO2 [VI] has been assigned on the basis of elemental, thermogravimetric analysis and IR- spectroscopy. The pK-a values of 6,7-dihydroxy-4-methylcoumarin in ethanol-water mixtures have been determined pH-metrically at different temperatures and ionic strengths. The thermodynamic parameters delta G, delta H and delta S have also been evaluated

Spectrophotometric studies on Ce [III], Th [IV], UO2 [VI] and VO [IV] complexes with 6,7-dihydroxy-4-methylcoumarin

The complexes of Ce [III], Th [IV], UO2 [VI] and VO [IV] with 6, 7-dihydroxy-4 methylcoumarin are investigated using spectrophotometric methods. The optimum conditions favoring the formation of their colored complexes are critically evaluated. The studies reveal that 1: 1, 1: 2 and 1: 3 [M: L] complexes are formed in solution. The stability constants of the different complexes are calculated. The effect of diverse ions is investigated. A spectrophotometric method for the determination of the named metal ions is represented also a photometric titration method using EDTA as titrant is also given. The proposed method is applicable to the ppm range the metal ions with high accuracy and precession