A Strontium-90 Sequestrant for First-Aid Treatment of Radiation Emergency

Abstract

In this study, hydrophilic porous polymer beads with phosphonic acid groups (PGMA-EGDMA-TTA-MP) were synthesized, and assessed as a radioactive strontium-90 sequestrant for the treatment of the radiation emergency. Strontium ions were rapidly absorbed into the blood from the gastrointestinal (GI) tract after oral administration to rats, and distributed to the target organ, i.e., bones. Over 40% of the administered strontium was absorbed into the blood, while the remainder was discharged in the feces within 48 h after the administration. When the PGMA-EGDMA-TTA-MP beads were administered to rats subsequent to the strontium solution, the strontium had accumulated less in the femur. Consequently, the oral administration of the PGMA-EGDMA-TTA-MP beads was effective in suppressing the absorption of strontium from the GI tract.Key words strontium-90; radiation emergency; polymeric adsorbent After the severe nuclear power plant accident at Fukushima in March, 2011, Japan has been suffering from the third most serious exposure to radiation following the Hiroshima and Nagasaki atomic bombs. 1,2) Since then, high levels (large amount) of the plant fuels and diverse fission products have been discharged from the plant facility into the environment. A similar accidental disaster has also occurred at the Chernobyl nuclear power plant in 1989. Strontium-90 (Sr-90) is one of artificial radioactive by-products of fission reactions within nuclear reactors that generate electricity. About 3% of the mass of the spent nuclear fuel consists of fission products including Sr-90.3) Due to its high energy of 0.54 MeV and long physical half-life of approximately 30 years by β − emission, Sr-90 is classified as a high-level waste. Its daughter radionuclide, yttrium-90, with a physical half-life of 64.1 h emits hard β − -particles with a maximum energy of 2.27 MeV. For a relatively fresh fission product mixture, another radioactive strontium, strontium-89 (Sr-89) with a maximum energy of 1.46 MeV and a half-life of 52.7 d by β − emission, can also be present.Since strontium belongs to the alkaline earth metals, its chemical behavior very closely resembles that of calcium, leading to its enrichment in bone and teeth in various organisms. After the radioactive strontium species enter the organisms, it deposits in the bone and bone marrow, and exposure from contaminated food and water is linked to bone cancer and leukemia 4); it takes hundreds of years to naturally decay to harmless levels (its biological half-life is over 50 years). Sr-90 is also considered the most important radioactive isotope in the environment and one of the most frequently occurring radionuclides in groundwater at nuclear facilities due to its long half-life. For instance, in Finland, the measured cumulative Sr-90 deposition in 1963-2005 averaged 1200 Bq/m 2 , of which 150 Bq/m 2 originated from the Chernobyl accident a quarter century ago, 5) and other large fraction from the atmospheric nuclear weapons tests in the 1960s. 6,7) From the viewpoint of radiation protectio...

Evaluation of Chlorella as a Decorporation Agent to Enhance the Elimination of Radioactive Strontium from Body

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Polymeric drugs: Advances in the development of pharmacologically active polymers

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Complexes of myo-inositol-hexakisphosphate (InsP6) with zinc or lanthanum to enhance excretion of radioactive strontium from the body

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