Polonium-210 Activity Research Articles

Excess of polonium-210 activity in the surface urban atmosphere. Part 2: origin of ²¹⁰Po excess.

The presence of significant (210)Po activity, unsupported by its grandparent radionuclide (210)Pb, in the surface atmosphere of industrialized regions can originate from human technical activities. In urban air, the activity ratio of (210)Po to (210)Pb might increase as a result of natural condensation and coagulation processes of relatively volatile (210)Po-containing species emitted during coal combustion processes. The presence of excess of (210)Po cannot be explained by its in-growth from radioactive decay of (210)Bi. About 50% of (210)Po radionuclide released during coal combustion processes can be emitted into air as gaseous or ultrafine products. Subsequently, these products are quickly attached to the surface of fine particles suspended in the air. As a result, an excess of (210)Po activity in aerosols has been reported. However, in this manner, As much as 11 GBq of (210)Po per year can enter the urban air from the local coal power plants in Lodz city, Poland.

Estimation of Polonium-210 activity in marine and terrestrial samples and computation of ingestion dose to the public in and around Kanyakumari coast, India

The brown mussel Perna perna, an effective bioindicator species for monitoring radioactive pollution, was used to evaluate the concentration of 210Po in and around the coastal areas of Kanyakumari, a Monazite rich region. 210Po concentration in P. perna collected from ten different locations in this region exhibited values ranging between 78.09 ± 5.5 and 320.00 ± 18.1 Bq/kg (wet). Kalluvilai recorded the maximum concentration of 210Po (320.00 ± 18.1Bq/kg), and hence further studies involving the activity of 210Po in other marine organisms and terrestrial samples were carried out from this site. The annual intake of 210Po by the population residing in this location via dietary sources was estimated. Similarly, the total annual committed effective dose to the public was found to be 2.24mSv/year. The results obtained were compared to the values reported by earlier studies in India and also in other countries.

Occurrence of 210Po in periwinkle (Littorina undulata, Gray, 1839) collected from Kudankulam (Gulf of Mannar (GOM), Southeast coast of India)

Polonium-210 activity concentration was analysed in the whole body tissue of periwinkle Littorina undulata collected from intertidal rocky shore along Kudankulam coast. We carried out the study for a period of 12months (2011–2012) focusing on three seasons. 210Po was found non-uniformly distributed among the periwinkles depending on the allometry. The 210Po accumulation showed a significant difference between seasons (p<0.05). Smaller sized winkles registered higher activity of 210Po compared to larger ones (p<0.05). The overall activity range of 210Po varied from 13.5 to 58.9Bq/kg (wet). The activity of 210Po was also quantified in seawater and intertidal sediments to calculate the biological concentration factor (BCF) and radiation dose rate. The dose rate to the winkles was performed using ERICA Assessment Tool and it was within the prescribed limit. The intake of 210Po through periwinkles delivered an effective dose in the range of 2.2–9.6μSv/y to human beings.

TASTRAK Spectroscopy of Polonium-210 Alpha-Particle Activity at Bone Surfaces: Evidence for a Concentrated Surface Deposit Less Than 3 μm Deep

The technique of alpha-particle spectroscopy by CR-39 type TASTRAK plastic has been used to study the depth distribution of natural alpha-particle emitters at the surface of human bone. The predominant component of this alpha-particle activity was 210Po supported by 210Pb, although a smaller activity of 226Ra was also detected. Autopsy samples of human femur and cranium were obtained from subjects age 63 to 86. Both cortical and trabecular surfaces were analyzed. The results indicate that 210Pb-supported 210Po is concentrated at the surfaces of human bone from elderly subjects, in a narrow band 3 microns deep or less, by a factor of about four. As a result, the alpha-particle dose to the nuclei of cells lining bone surfaces is around 1.8 times greater than that calculated for a uniform volume distribution. Polonium-210 activity indicates the distribution of 210Pb, and of stable lead, received by continuous intake throughout life at a very low level. A persistent bone surface concentration of lead and other osteotropic metals may be associated with the hypermineralized layer about 1 micron thick which occurs at the surface of resting bone mineral.

An ion-exchange model of lead-210 and lead uptake in a foliose lichen; application to quantitative monitoring of airborne lead fallout

Lead, 210Pb and 210Po levels were determined in dated sequential growth of thalli of the foliose lichen Flavoparmelia baltimorensis from Great Falls and Plummers Island, Maryland. An ion-exchange model for uptake of Pb and 210Pb applied to these data is consistent with the experimentally measured Pb partition coefficient between water and lichen as well as the expected lead concentrations in rain. Lead-210/Polonium-210 activity ratios are significantly elevated in very young growth (<3 years old), as expected from model calculations. Retrospective Pb fallouts are computed which reflect the drop in gasoline lead emissions in the period sampled (1973–1986). With experimental determination of partition coefficients this methodology is a basis for retrospective quantitative monitoring of other airborne heavy metals using foliose lichens.

Detection of a Nonuniform Distribution of Polonium-210 on the Moon with the Apollo 16 Alpha Particle Spectrometer

The polonium-210 activity of the lunar surface is significantly larger than the activity of its progenitor radon-222. This result establishes unequivocally that radon emanation from the present-day moon varies considerably within the 21-year half-life of lead-210, the parent nuclide of polonium-210. There are large variations and well-localized enhancements in polonium-210 activity over much of the moon's surface.

Polonium-210 and lead-210 in the marine environment

A method is outlined for the determination of lead-210 and polonium-210 in sea water by solvent extraction, followed by electrodeposition and alpha counting. Data are given for the lead-210 and polonium-210 content of twenty nine samples collected at a depth of 20 m in the sea around the Cape of Good Hope during March 1969. The mean activities of lead-210 and polonium-210 in these sea water samples were 38 × 10 −15 c/1 and 20 × 10 −15 c/1 respectively. Real variations in the concentrations of these nuclides were found to exist, and these could in part be ascribed to different water masses and current systems. The lead-210 and polonium-210 contents of eleven Zooplankton and three phytoplankton samples collected during the same period were also determined. Mean values for lead-210 and polonium-210 in Zooplankton were 33 pc/kg wet weight and 399 pc/kg wet weight respectively. A correlation between these nuclides in Zooplankton was found to exist, the lead-210 activity being on the average one twelfth of the polonium-210 activity. An attempt has been made to evaluate the biogeochemical balance of lead-210 and polonium-210 in the marine environment. Using the data presented, and making certain stated assumptions, the removal times of these nuclides from the upper mixed layer have been calculated. These times were found to be about 5 yr for lead-210 and 0.6 yr for polonium-210.

Polonium-210 activity in the lungs of cigarette smokers.

In an attempt to contribute additional information on the natural radiation burden applied to the human body the polonium-210 content in different parts of the lungs of human cigarette smokers and nonsmokers was measured. The average activity of polonium-210 (210Po) assessed in some brands of cigarettes is summarized in table form. The 210Po inhalation rate was determined to be 2% for an individual smoking 20 cigarettes daily. The 210Po activities found in different parts of the lung tissue of both smoking and nonsmoking individuals are summarized in table form. For these analyses the parenchymal tissue the bifurcation and the bronchial tissue were dissected prior to measurement. The lung tissue dissected from heavy smokers was shown to contain 3-4 times the 210Po activity found in the lungs of nonsmokers.