{"id":7913,"date":"2025-04-27T13:10:36","date_gmt":"2025-04-27T04:10:36","guid":{"rendered":"https:\/\/www.envraddb.go.jp\/entesttest\/?page_id=7913"},"modified":"2026-05-27T16:37:05","modified_gmt":"2026-05-27T07:37:05","slug":"strontium","status":"publish","type":"page","link":"https:\/\/www.envraddb.go.jp\/en\/special\/tec-info\/strontium\/","title":{"rendered":"Strontium 90\uff0890<\/span>Sr\uff09"},"content":{"rendered":"
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Overview<\/h2>\r\n <\/div>\r\n
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What is  90<\/span>Sr?*1, *2, *3<\/span><\/h3>\r\n <\/div>\r\n
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90<\/span>Sr is a radioactive isotope of strontium with a half-life of\r\n 28.91 years. It is a \"pure \u03b2-emitting nuclide\" that undergoes \u03b2 decay, emitting beta rays but no \u03b3 rays.\r\n Radioactive strontium isotopes are primarily produced through the fission of 235<\/span>U and other fissile\r\n materials and are known for their high fission yield. There are multiple radioactive isotopes of Sr. Due to\r\n their half-lives and the nature of the radiation they emit, 89<\/span>Sr and 90<\/span>Sr are the primary\r\n targets for environmental radiation monitoring.\r\n <\/p>\r\n <\/div>\r\n\r\n <\/div>\r\n

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90<\/span>Sr analysis objective*4<\/span><\/h3>\r\n <\/div>\r\n
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Strontium belongs to group 2 (alkaline earth metals) of the periodic table. Its\r\n chemical behavior is similar to other homologous elements such as calcium and barium, which means that when\r\n entering the body, strontium is deposited in the bone tissue together with calcium, resulting in bone marrow\r\n exposure and other health effects. Consequently, when released into the environment due to atmospheric\r\n nuclear testing or nuclear power plant accidents, it is an important nuclide in exposure dose assessments to\r\n monitor along with radioactive iodine and radioactive cesium.<\/p>\r\n <\/div>\r\n\r\n <\/div>\r\n\r\n

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Main analysis methods of  90<\/span>Sr (Based on Separation and Purification)<\/h3>\r\n <\/div>\r\n
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Ion exchange method<\/h4>\r\n <\/div>\r\n
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The ion exchange method is a method for separating strontium from other\r\n alkaline earth metals, such as calcium, by utilizing the difference in the distribution coefficients of\r\n cationic metals for the cation exchange resin. A sample solution is passed through a column filled with\r\n strongly acidic cation exchange resin. For samples with high calcium concentrations exceeding the ion\r\n exchange capacity of the resin column, a series of resin columns may be employed to ensure complete\r\n separation.<\/p>\r\n <\/div>\r\n <\/div>\r\n

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Fuming nitric acid method<\/h4>\r\n <\/div>\r\n
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A method of separating Sr and Ca by utilizing the difference in solubility\r\n between strontium nitrate and calcium nitrate at a nitric acid specific gravity of 1.45 (about 77% of\r\n nitric acid concentration). Since complete separation and removal of Ca cannot be achieved in a single\r\n operation, it is necessary to repeat the formation of nitrate precipitates, and fuming nitric acid must\r\n be handled with extreme care. Additionally, separation and removal of homologous elements other than Ca\r\n are required.<\/p>\r\n <\/div>\r\n <\/div>\r\n

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Oxalate process<\/h4>\r\n <\/div>\r\n
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This is a method to separate Sr from many cationic metals by utilizing the\r\n difference in solubility of oxalate salts. While this method is simple because Ca is not separated and\r\n removed, it has disadvantages compared to the ion exchange method, such as the large volume of equipment\r\n used and complicated analytical procedures. In addition, when strontium carbonate precipitates are used\r\n as the measurement sample, calcium carbonate precipitates are included in the measurement sample because\r\n Ca is not separated and removed. As a result, the analysis is limited to 90<\/span>Sr only, as\r\n 89<\/span>Sr cannot be measured.\r\n <\/p>\r\n <\/div>\r\n <\/div>\r\n\r\n\r\n\r\n <\/div>\r\n <\/div>\r\n\r\n <\/section>\r\n

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Analytical flow (ion exchange method)<\/h2>\r\n <\/div>\r\n
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Seawater sample<\/p>\r\n <\/div>\r\n

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Large ion exchange resin column<\/p>\r\n