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At least 19 recordsLinked to original sources
PubMed2001

Formation and emission of volatile polonium compound by microbial activity and polonium methylation with methylcobalamin.

We observed biologically mediated emission of Po from culture solution inoculated sea sediment extract and incubated under natural light/dark cycle condition or dark condition the emitted Po compound would be lipophilic because of effective collection in organic solvent. Sterilization of the culture medium with antibiotics or CuSO4 completely suppressed growth of microorganisms and resulted in no emission of Po, indicating biological activity of microorganisms is responsible for formation and emission of volatile Po compound. Po emission also occurred when seawater was used as a culture medium. Our finding indicates a possibility of biotic source for atmospheric Po in the environment, which has been believed to be originated from abiotic sources. We compared emission behavior of Po and S in the culture experiments, the elements belong to XVI group in the Periodical Table, and consider that their emission mechanisms involved would be different though the emission of both elements is supported by biological activity of microorganisms. One of the chemical forms of S emitted was confirmed to be dimethyl sulfide (DMS) but that of Po is not known. Methylation experiments of Po with methylcobalamin demonstrated a formation and emission of volatile Po compound. The methylation of Po with methylcobalamin might be related to the observed Po emission in the culture experiments.

Air Pollutants↗
PubMed1975

Polonium-210: lead-210 ratios as an index of residence times of insoluble particles from cigarette smoke in bronchial epithelium.

Lead-210 and its granddaughter polonium-210 are both natural constituents of cigarette smoke, the 210Pb being enriched in insoluble particles derived from sintered tobacco trichome tips. These particles are stripped of the polonium on combustion, and thus the polonium begins growth at the time of inhalation. Polonium-210 is found in bronchial tissues of smokers, and evidence shows that 210Pb is present at these sites in excess of the polonium. On the assumption that all polonium arises from ingrowth from the insoluble particles, one may calculate from the polonium-lead ratio the mean residence time of these particles. The half-life of polonium (138 days) is almost ideal for this purpose, and its alpha radiation makes measurements of very low concentrations possible. This technique is the first available to assess residence time for inhaled particles in the bronchial epithelium, an important datum because of the vulnerability of bronchial tissues to disease. Measurements from three smokers and two non-smokers show that 210Pb from natural aerosols also is concentrated at bronchial bifurcations, but little 210Pb is associated with this soluble lead. This fact makes estimates of residence time in bronchial epithelium of smokers (3-5 months in these preliminary data) likely to be low.

Adolescent↗
PubMed2001

Polonium 210Po in cigarettes produced in Poland.

This paper discusses the results of 210Po determinations in the fourteen most frequently smoked brands of cigarettes, which constitute over 80% of total cigarette consumption in Poland. The 210Po activity in the cigarette samples analysed (tobacco, ash, filter before and after smoking) were measured using alpha spectrometry (Canberra-Packard). The data indicates that there is considerable variation in the polonium content of these brands. The highest 210Po content per sample was found in the cheap "Popularne" brand (24.12 mBq), the lowest in "Caro" (4.23 mBq). There was also a large difference between the polonium remaining in the ash in comparison with its total content in the tobacco in all the brands (from 4.3% for "Golden American" to 71.0% for "Sobieski King-Size"). The analysis has demonstrated that filters absorbed only a small amount of the polonium contained in the tobacco. "Caro" cigarettes have the most efficient filter, retaining 25.1% of the polonium contained in the tobacco, but most filters absorbed only 0.1-7.2% of polonium. The daily inhalation of 210Po by Polish smokers who get through one pack per day ranges from 20 to 215 mBq, but people smoking two or more packs of "Popularne" brand will inhale over 430 mBq of polonium per day.

Humans↗
PubMed1994

Polonium metabolism in adult female baboons.

The biokinetics of polonium in nonhuman primates (Papio anubis) has been studied after intravenous injection of 210Po citrate. The urinary excretion of polonium in the baboon could be described by a single exponential function with a half-time of 15.6 days. Excretion fractions of polonium were found to be markedly different from those reported for other species, including humans. Polonium-210 was found to be distributed throughout the soft tissues of the baboon with 29% of the injected polonium being deposited in liver, 7% in kidneys and 0.6% in spleen. Retention of polonium in all tissues exhibited single exponential functions; however, the biological half-times were variable, ranging from 15 to 50 days.

Animals↗
PubMed2001

A systemic biokinetic model for polonium.

Although the biokinetics of polonium has been studied extensively, interpretation of the data is complicated by potential differences with species and route of exposure and the questionable reliability of much of the reported excretion data for man. A study was undertaken to identify the data that are most likely to represent the typical behavior of polonium and apply those data to construct an improved, physiologically realistic systemic biokinetic model for polonium in man. Such a model is needed for interpretation of urinary excretion data for workers exposed to 210Po and reconstruction of the radiation doses received by those workers. This paper reviews the database on the biokinetics of polonium and describes a new systemic biokinetic model for polonium in man.

Air Pollutants, Occupational↗
PubMed1990

N-(2,3-dimercaptopropyl)phthalamidic acid (DMPA) increases polonium-210 excretion.

Polonium-210 is one of the most hazardous radionuclides. As recently as 1988, there have been concerns regarding accidental exposures of humans to it. Yet, there have been no studies on the effectiveness of the newer dithiol chelating agents in increasing the excretion of this radioactive heavy metal. In order to accomplish this, a safe and effective method for determining the radioactivity of polonium-210, an alpha emitter, in the feces was developed. The excretion of polonium-210 was studied by giving male Sprague-Dawley rats 210Po (3.33 x 10(7) cpm/kg, intraperitoneal); 1 h later they were given either 5% sodium bicarbonate, N-(2,3-dimercaptopropyl)phthalamidic acid (DMPA) or meso-dimercaptosuccinic acid (DMSA) (0.20 mmol/kg, subcutaneous). Treatment was repeated daily for 12 days. DMPA and DMSA increased the urinary excretion of 210Po, as compared to control animals, 8-fold and 5-fold, respectively. DMPA increased the fecal excretion of 210Po compared to the other treatments and also decreased the level of 210Po in the spleen, a radiosensitive organ. DMPA (0.20 mmol/kg, intravenous) increased biliary levels of 210Po 5-fold compared to controls. The results indicate that DMPA has greater specificity in chelating and increasing the excretion of 210Po than DMSA.

Animals↗
PubMed2003

Polonium 210Po in the phytobenthos from Puck Bay.

The aim of the work was to determine the 210Po content in phytobenthos species (seaweeds and angiosperms) from Puck Bay (southern Baltic). Alpha spectrometry was used to measure and calculate the activities and concentrations of polonium 210Po in the phytobenthos. The activity of 210Po in Puck Bay waters was determined to estimate the bioconcentration factors (BCF) of these plants. The 210Po concentration in water was estimated at 0.25 mBq dm(-3). The lowest polonium concentration in the phytobenthos was found in Cladophora rupestris (0.12 Bq kg(-1) wet wt.), the highest in Chara crinita (1.12 Bq kg(-1) wet wt.). Polonium is accumulated in these phytobenthos species; the bioconcentration factors (BCF) ranged from 450 to 4400.

Baltic States↗
PubMed1984

Polonium-210 in the environment around a radioactive waste disposal area and phosphate ore processing plant.

Polonium-210 concentrations were determined for soil, vegetation and small mammal tissues collected at a solid radioactive waste disposal area, near a phosphate ore processing plant and at two rural areas in southeastern Idaho. Polonium concentrations in media sampled near the radioactive waste disposal facility were equal to or less than values from rural area samples, indicating that disposal of solid radioactive waste at the Idaho National Engineering Laboratory Site has not resulted in increased environmental levels of polonium. Concentrations of 210Po in soils, deer mice hide and carcass samples collected near the phosphate processing plant were statistically (P less than or equal to 0.05) greater than the other sampling locations; however, the mean 210Po concentration in soils and small mammal tissues from sampling areas near the phosphate plant were only four and three times greater, respectively, than control values. No statistical (P greater than 0.05) difference was observed for 210Po concentrations in vegetation among any of the sampling locations.

Animals↗
PubMed1986

Lung cancer: is the increasing incidence due to radioactive polonium in cigarettes?

This paper presents clinical, experimental, and epidemiologic evidence to help explain the rapidly increasing incidence of primary lung cancer, with recently observed reversal in leading cell type from squamous cell to adenocarcinoma. It postulates that this may be due to changes in modern cigarettes, with or without filters, which allow inhalation of increased amounts of radioactive lead and polonium and decreased amounts of benzopyrene. This hypothesis is based upon measurements of increased concentrations of radioactive polonium in the lungs of cigarette smokers, in modern tobaccos grown since 1950, and in high-phosphate fertilizers used for tobacco farming in industrialized countries. Critical support for this thesis is based upon experimental animal studies in which lung cancers that resemble adenocarcinomas are induced with as little as 15 rads of radioactive polonium, equal to one fifth the dosage inhaled by cigarette smokers who average two packs a day during a 25-year period.

Adenocarcinoma↗
PubMed1975

Lung cancer induced in hamsters by low doses of alpha radiation from polonium-210.

Lung cancers have been induced in 9 to 53 percent of hamsters given multiple intratracheal instillations of polonium-210 in amounts yielding lifetime exposures of 15 to 300 rads to the lungs. Cigarette smokers have previously been estimated to receive 20 rads to areas of the bronchial epithelium from deposited polonium-210. This finding thus supports the hypothesis that alpha radiation resulting from the polonium-210 or lead-210 present in cigarette smoke may be a significant causative factor in human lung cancer.

Adenocarcinoma↗
PubMed1964

RADIUM-226 AND POLONIUM-210 IN LEAF TOBACCO AND TOBACCO SOIL.

Contents of radium-226 and polonium-210 in leaf tobacco and tobacco-growing soils vary with the source. The differences may result from production locality, culture, and curing. The polonium seems to be not entirely derived from the radium; plants probably take it up from the soil or air.

Florida↗
PubMed2004

Polonium-210 budget in cigarettes.

Due to the relatively high activity concentrations of (210)Po and (210)Pb that are found in tobacco and its products, cigarette smoking highly increases the internal intake of both radionuclides and their concentrations in the lung tissues. That might contribute significantly to an increase in the internal radiation dose and in the number of instances of lung cancer observed among smokers. Samples of most frequently smoked fine and popular brands of cigarettes were collected from those available on the Egyptian market. (210)Po activity concentrations were measured by alpha spectrometry, using surface barrier detectors, following the radiochemical separation of polonium. Samples of fresh tobacco, wrapping paper, fresh filters, ash and post-smoking filters were spiked with (208)Po for chemical recovery calculation. The samples were dissolved using mineral acids (HNO(3), HCl and HF). Polonium was spontaneously plated-out on stainless steel disks from diluted HCl solution. The (210)Po activity concentration in smoke was estimated on the basis of its activity in fresh tobacco and wrapping paper, fresh filter, ash and post-smoking filters. The percentages of (210)Po activity concentrations that were recovered from the cigarette tobacco to ash, post-smoking filters, and smokes were assessed. The results of this work indicate that the average (range) activity concentration of (210)Po in cigarette tobacco was 16.6 (9.7-22.5) mBq/cigarette. The average percentages of (210)Po content in fresh tobacco plus wrapping paper that were recovered by post-smoking filters, ash and smoke were 4.6, 20.7 and 74.7, respectively. Cigarette smokers, who are smoking one pack (20 cigarettes) per day, are inhaling on average 123 mBq/d of (210)Po and (210)Pb each. The annual effective doses were calculated on the basis of (210)Po and (210)Pb intake with the cigarette smoke. The mean values of the annual effective dose for smokers (one pack per day) were estimated to be 193 and 251 microSv from (210)Po and (210)Pb, respectively.

Egypt↗
PubMed2001

Human absorption and retention of polonium-210 from caribou meat.

The gastrointestinal (GI) absorption factors and the biological retention times for polonium were determined for a group of 14 volunteers--seven men and seven women--from Saskatoon, Saskatchewan, Canada. Each volunteer consumed 2.0 kg of caribou meat containing known amounts of naturally occurring 210Po. Urine and faecal samples were collected for up to 65 days after meat consumption and analysed for 210Po. The average GI absorption factor for the 14 volunteers was 56 +/- 4% (range = 31-71%), not significantly different from the ICRP value of 50%. About 3% of absorbed polonium underwent prompt excretion by the urinary pathway. The remainder was retained by the body with a half-time >100 days, compared to the ICRP value of 50 days. The effect of these findings increases the dose estimate for ingestion of 210Po in food by a factor of 1.5 to 3.5. Thus, background doses to people consuming caribou and reindeer may be higher than previously thought.

Administration, Oral↗
PubMed1966

Polonium-210 content of human tissues in relation to dietary habit.

Concentrations of polonium-210, a natural fallout nuclide, in human placentas collected in northern Canada ranged up to 27.8 picocuries per 100 grains, or 80 times the average United Kingdom value. High levels are related to the inclusion of reindeer or caribou meat in the diet, and a correlation exists between the eoncentrations of polonium-210 and cesium-137 in the placentas.

Animals↗
PubMed1966

Source of lead-210 and polonium-210 in tobacco.

Test plants were grown within a chamber enriched with radon-222 in the atmosphere, in tobacco fields with different sources of phosphate-containing fertilizer, and in culture containing lead-210 in the nutrient solution. Harvested leaves were subjected to three curing conditions. The major portion of the lead-210 in the plant was probably absorbed through the roots. Airborne radon 222 and its daughters contributed much less to the plant's content of lead-210 and of polonium-210. The stage of leaf development and the methods used to cure the leaf affected the final amount of polonium-210 in tobacco leaf.

Lead↗