Strontium radioactivity

Among the honey types studied, honeydew honey exhibited the best indicator capabilities of all of the elements and radionuclides. By comparison with the aforementioned types of honey, the transfer of Cs and Rb into honeydew honey was an order of magnitude higher, with transfers of 8.56 and 1.50 percent, respectively. Transfers for (21.1 percent), Pb (5.42 percent), Cu (3.85 percent), Ca (2.48 percent), Cr (1.34 percent), and Ni (<0.960) nearly equalled or exceeded 1 percent. On the other hand, the soil macroelement Fe showed a very low transfer (0.039 percent) from soils into honeydew honey. Strontium showed a similar behavior (<0.042 percent), so it seems that honey could not be used very successfully as an indicator of environmental pollution with strontium radioactive isotopes. The results show that samples of honey, especially honeydew honey, can indicate the consequences of global pollution events as well as events on a local scale. 

These chemical effects become important in medicine because living systems operate mostly through the reactions of enzymes, which catalyze all sorts of metabolic reactions but are very sensitive to small changes in their environment. Such sensitivity can lead to preferential absorption of some deleterious isotopes in place of the more normal, beneficial ones. One example in metabolic systems can be found in the incorporation of a radioactive strontium isotope in place of calcium. 

Properties. Strontium is a hard white metal having physical properties shown in Table 1. It has four stable isotopes, atomic weights 84, 86, 87, and 88 and one radioactive isotope, strontium-90 [10098-97-2] which is a product of nuclear fission. The most abundant isotope is strontium-88. 

The properties of hydrated titanium dioxide as an ion-exchange (qv) medium have been widely studied (51—55). Separations include those of alkaH and alkaline-earth metals, zinc, copper, cobalt, cesium, strontium, and barium. The use of hydrated titanium dioxide to separate uranium from seawater and also for the treatment of radioactive wastes from nuclear-reactor installations has been proposed (56). 

Barium titanate thin films can be deposited on various substances by treating with an aqueous solution containing barium salts and an alkanolamine-modifted titanate such as TYZOR TE (151). In a similar fashion, reaction of a tetraalkyl titanate with an alkah metal hydroxide, such as potassium hydroxide, gives oxyalkoxide derivatives (KTi O(OR) ), which can be further processed to give alkali metal titanate powders, films, and fibers (152—155). The fibers can be used as adsorbents for radioactive metals such as cesium, strontium, and uranium (156). 

The radiation hazard associated with fallout from nuclear weapons testing arises from radioactive isotopes such as these. One of the most dangerous is strontium-90. In the form of strontium carbonate, SrC03, it is incorporated into the bones of animals and human beings, where it remains far a lifetime. 

Half-lives span a very wide range (Table 17.5). Consider strontium-90, for which the half-life is 28 a. This nuclide is present in nuclear fallout, the fine dust that settles from clouds of airborne particles after the explosion of a nuclear bomb, and may also be present in the accidental release of radioactive materials into the air. Because it is chemically very similar to calcium, strontium may accompany that element through the environment and become incorporated into bones once there, it continues to emit radiation for many years. About 10 half-lives (for strontium-90, 280 a) must pass before the activity of a sample has fallen to 1/1000 of its initial value. Iodine-131, which was released in the accidental fire at the Chernobyl nuclear power plant, has a half-life of only 8.05 d, but it accumulates in the thyroid gland. Several cases of thyroid cancer have been linked to iodine-131 exposure from the accident. Plutonium-239 has a half-life of 24 ka (24000 years). Consequently, very long term storage facilities are required for plutonium waste, and land contaminated with plutonium cannot be inhabited again for thousands of years without expensive remediation efforts. 

Pecher, C. 1941 Biological investigations with radioactive calcium and strontium. Proceedings of the Society for Experimental Biology Medicine 46 86-91. 

Pavlotskaya, F. I., Surotkevichiene, R. and Levina, G. P. (1974). State of strontium-90, cesium-137 and cerium-144 in radioactive fallout, page 111 in Nuclear Meteorology, Report No. TT-74-50011, also Report No. CONF-690670, Makhon ko, K. P. and Malakhov, S. G., Eds. (National Technical Information Service, Springfield, Virginia). 

Robertson [ 57 ] has measured the adsorption of zinc, caesium, strontium, antimony, indium, iron, silver, copper, cobalt, rubidium, scandium, and uranium onto glass and polyethylene containers. Radioactive forms of these elements were added to samples of seawater, the samples were adjusted to the original pH of 8.0, and aliquots were poured into polyethylene bottles, Pyrex-glass bottles and polyethylene bottles contained 1 ml concentrated hydrochloric acid to bring the pH to about 1.5. Adsorption on the containers was observed for storage periods of up to 75 d with the use of a Nal(Tl) well crystal. Negligible adsorption on all containers was registered for zinc, caesium, strontium, and... 

Common radioactive material in use today includes the alpha emitters Americium-241 and Plutonim-238 the beta emitters Phosporus-32 and Strontium-90 and the gamma emitters Cesium-137, Cobalt-60, and Iridium-192 [44], These materials are commonly used in smoke detectors, oil exploration, industrial gauges, food and mail irradiation, cancer therapy, industrial radiography, and in research laboratories. 

Radiotherapy is a local treatment aiming to achieve local control or cure of locally confined tumours. It cannot treat metastases. Radiotherapy may be administered as external beam radiotherapy with X-rays or gamma rays, in sealed radioactive sources (e.g. prostate brachytherapy), or unsealed sources (e.g. orally administered radioiodine for thyroid cancer, intravenous strontium-89 for bone metastases). In external beam radiotherapy, the X-ray or gamma ray beams are targeted at the tumour to damage and kill the tumour cells. Inevitably, surrounding normal tissues are also affected resulting in the early and late side effects of radiotherapy. 

ISOTOPES There are 29 isotopes of strontium, ranging from Sr-75 to Sr-102. The four natural forms of strontium are stable and not radioactive. These stable isotopes are Sr-84, which constitutes 0.56% of the elemenfs existence on Earth Sr-86, which makes up 9.86% Sr-87, which accounts for 7.00% of the total and Sr-88, which makes up 82.58% of strontium found on Earth. The remaining isotopes are radioactive with half-lives ranging from a few microseconds to minutes, hours, days, or years. Most, but not all, are produced in nuclear reactors or nuclear explosions. Two important radioisotopes are Sr-89 and Sr-90. 

Strontium-90, a radioactive strontium isotope with a half-hfe of 29 years, is a dangerous fallout source of radiation from atmospheric nuclear bombs. If a person is exposed to it, it will rapidly accumulate in bone tissue and interfere with the production of new red blood cells... 

Some compounds, such as strontium chromate and strontium fluoride, are carcinogens and toxic if ingested. Strontium-90 is particularly dangerous because it is a radioactive bone-seeker that replaces the calcium in bone tissue. Radiation poisoning and death may occur in people exposed to excessive doses of Sr-90. Strontium-90, as well as some other radioisotopes that are produced by explosions of nuclear weapons and then transported atmospherically, may be inhaled by plants and animals many miles from the source of the detonation. This and other factors led to the ban on atmospheric testing of nuclear and thermonuclear weapons. 

Fleer V. N. (1982). The dissolution kinetics of anorthite (CaAl2Si20g) and synthetic strontium feldspar (SrAl2Si20g) in aqueous solutions at temperatures below 100°C With applications to the geological disposal of radioactive nuclear wastes. Ph.D. diss., Pennsylvania State University University Park. 

Studies are being conducted by the Pacific Northwest National Laboratory (PNNL) to investigate the use of clinoptilolite as an in situ permeable barrier to strontium (Sr °) migration in groundwater at the site referred to as the 100-N area of the Hanford Site. This technology uses clinoptilolite to absorb radioactive Sr ° from groundwater. 

Researchers claim that lonsiv TIE-96 can remove 99.9% of the plutonium, strontium, and cesium from waste solutions, allowing for wastes to be divided into separate low-level and high-level radioactive waste streams, where they can be safely and efficiently processed for disposal. 

Some zeolites have a strong affinity for particular cations. Clinoptilolite (HEU) is a naturally occurring zeolite which sequesters caesium, and is used by British Nuclear Fuels (BNFL) to remove Cs from radioactive waste, exchanging its own Na ions for the radioactive Cs cations. Similarly, zeolite A can be used to recover radioactive strontium. Zeolites were heavily used in the clean up operations after the Chernobyl and Three Mile Island incidents. 

Radioactive sources of commercial interest are y- and /3-ray emitters. The choice of sources has narrowed down to roughly three elements— cobalt-60, strontium-90, and cesium-137—as a result of their useful characteristics, reasonably long half-life, availability, and cost. 

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