Skip directly to site content Skip directly to page options Skip directly to A-Z link. Radiation Emergencies. Section Navigation. Facebook Twitter LinkedIn Syndicate. Radioisotope Brief: Strontium Minus Related Pages. Half-life : Where does it come from? Principal uses of strontium compounds are in pyrotechnics, for the brilliant reds in fireworks and warning flares and in greases. A little is used as a getter in vacuum tubes to remove the last traces of air.
Most strontium is used as the carbonate in special glass for television screens and visual display units. Although strontium is a dangerously radioactive isotope, it is a useful by-product of nuclear reactors from whose spent fuel is extracted. Its high-energy radiation can be used to generate an electric current, and for this reason it can be used in space vehicles, remote weather stations and navigation buoys. Strontium is commonly occurs in nature, formung about 0. Celestite occurs frequently in sedimentary deposits of sufficient size, thus the development of mining facilities attractive.
World production of strontium ores is about Foods containing strontium range from very low e. Strontium compounds that are water-insoluble can become water-soluble, as a result of chemical reactions. The water-soluble compounds are a greater threat to human health than the water-insoluble ones.
Therefore, water-soluble forms of strontium have the opportunity to pollute drinking water. Fortunately the concentrations in drinking water are usually quite low.
People can be exposed to small levels of radioactive strontium by breathing air or dust, eating food, drinking water, or by contact with soil that contains strontium. We are most likely to come in contact with strontium by eating or drinking. Strontium concentrations in food contribute to the strontium concentrations in the human body.
Foodstuffs that contain significantly high concentrations of strontium are grains, leafy vegetables and dairy products. For most people, strontium uptake will be moderate. Rather, strontium is usually found in nature in the form of minerals. Strontium can form a variety of compounds. Strontium compounds do not have any particular smell. There are two types of strontium compounds, those that dissolve in water and those that do not. Natural strontium is not radioactive and exists in four stable types or isotopes , each of which can be written as 84 Sr, 86 Sr, 87 Sr, and 88 Sr, and read as strontium eighty-four, strontium eighty-six, etc.
All four isotopes behave the same chemically, so any combination of the four would have the same chemical effect on your body. Rocks, soil, dust, coal, oil, surface and underground water, air, plants, and animals all contain varying amounts of strontium. Typical concentrations in most materials are a few parts per million ppm.
After the strontium is extracted from strontium ore, it is concentrated into strontium carbonate or other chemical forms by a series of chemical processes. Strontium compounds, such as strontium carbonate, are used in making ceramics and glass products, pyrotechnics, paint pigments, fluorescent lights, medicines, and other products. Strontium can also exist as radioactive isotopes. Each radioactive element, including strontium, constantly gives off radiation, and this process changes it into an isotope of another element or a different isotope of the same element.
This process is called radioactive decay. The radioactive half-life is the time that it takes for half of a radioactive strontium isotope to give off its radiation and change into a different element. The radioactive isotope 89 Sr is used as a cancer therapeutic to alleviate bone pain. Quantities of radioactive strontium, as well as other radioactive elements, are measured in units of mass grams or radioactivity curies or becquerels.
Both the curie Ci and the becquerel Bq tell us how much a radioactive material decays every second. The becquerel is a new international unit known as the SI unit, and the curie is an older unit; both are used currently.
A becquerel is the amount of radioactive material in which 1 atom transforms every second. One curie is the amount of radioactive material in which 37 billion atoms transform every second; this is approximately the radioactivity of 1 gram of radium. Stable and radioactive strontium compounds in the air are present as dust. Emissions from burning coal and oil increase stable strontium levels in air. The average amount of strontium that has been measured in air from different parts of the United States is 20 nanograms per cubic meter a nanogram is a trillion times smaller than a gram.
Most of the strontium in air is in the form of stable strontium. Very small dust particles of stable and radioactive strontium in the air fall out of the air onto surface water, plant surfaces, and soil either by themselves or when rain or snow falls. These particles of strontium eventually end up back in the soil or in the bottoms of lakes, rivers, and ponds, where they stay and mix with stable and radioactive strontium that is already there.
In water, most forms of stable and radioactive strontium are dissolved. Stable strontium that is dissolved in water comes from strontium in rocks and soil that water runs over and through. Only a very small part of the strontium found in water is from the settling of strontium dust out of the air.
Some strontium is suspended in water. Some 90 Sr is suspended in water. In general, the amount of 90 Sr that has been measured in drinking water in different parts of the United States by EPA is less than one tenth of a picocurie for every liter of water 0. Strontium is found naturally in soil in amounts that vary over a wide range, but the typical concentration is 0.
The disposal of coal ash, incinerator ash, and industrial wastes may increase the concentration of strontium in soil. Generally, the amount of 90 Sr in soil is very small and is only a fraction of the total concentration of strontium in soil.
Higher concentrations of 90 Sr in soil may be found near hazardous waste sites, radioactive waste sites, and Department of Energy facilities located around the United States.
A major portion of stable and radioactive strontium in soil dissolves in water, so it is likely to move deeper into the ground and enter groundwater. However, strontium compounds may stay in the soil for years without moving downward into groundwater.
In the environment, chemical reactions can change the water-soluble stable and radioactive strontium compounds into insoluble forms. In some cases, water-insoluble strontium compounds can change to soluble forms. Strontium is found nearly everywhere in small amounts, and you can be exposed to low levels of strontium by breathing air, eating food, drinking water, or accidentally eating soil or dust that contains strontium.
Food and drinking water are the largest sources of exposure to strontium. Because of the nature of strontium, some of it gets into fish, vegetables, and livestock. Grain, leafy vegetables, and dairy products contribute the greatest percentage of dietary strontium to humans. The concentration of strontium in leafy vegetables, such as cabbage, grown in the United States is less than 64 mg in a kg of the fresh vegetables i.
For most people, the intake of strontium will be moderate. You can be exposed to low levels of 90 Sr by eating food, drinking water, or accidentally eating soil or dust that contains 90 Sr. Food and drinking water are the largest sources of exposure to 90 Sr.
Because of the nature of 90 Sr, some of it gets into fish, vegetables, and livestock. Grain, leafy vegetables, and dairy products contribute the greatest percentage of dietary 90 Sr to humans. Most strontium is formed when the element rubidium decays. Each area on the planet has its own unique ratio of strontium ions depending on the local geology, according to Curiosity. These strontium ions enter our food and water supply and end up in our bodies.
Since strontium ions are chemically similar to calcium and therefore bind tightly to calcium sensing receptors, strontium can be accidentally incorporated into teeth, bones and seashells in place of calcium. Scientists measure the levels of strontium isotopes Sr and Sr in ancient teeth, bones or seashells, and then they compare the ratio of these two isotopes — either to one another or to another element, such as calcium or zinc — to determine a specimen's place of origin, diet or age.
In one particular case study, anthropologists discovered a 1,year-old mass grave in the ancient Native American settlement of Cahokia near modern-day St. The grave held the remains of 39 people, whose bones revealed signs of a violent end. For a long time, scientists thought these people were foreigners who had been killed as war captives or intruders. But after conducting recent strontium tests on the victims' teeth, the scientists found that most of the people had been born and raised in Cahokia.
Studying strontium isotope levels in bone has also allowed scientists to better understand our ancestors' diets, knowing that plants tend to be higher in natural strontium than meat. In , for example, Austrian researchers compared strontium and zinc levels to support the hypothesis that Roman gladiators were vegetarians who ate mainly barley, beans and dried fruits, according to RSC.
Strontium testing occurs in the ocean as well. For every 1, calcium atoms, seashells contain only a few strontium atoms, according to Sea Change Science. Research has shown that the relative levels of seawater Sr and Sr has changed over time. Over the last 40 million years, ocean levels of strontium have steadily increased.
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