Strontium is a naturally occurring chemical element, recognized by the symbol Sr and atomic number 38. It belongs to the alkaline earth metals, a group of reactive elements. While strontium itself does not exist freely in nature due to its reactivity, it is commonly found combined with other elements in minerals, soil, and water. When strontium forms an ion, it carries an electrical charge, which influences its interactions in various environments and within the human body.
What Strontium Ion Is
An ion is an atom or molecule that has gained or lost one or more electrons, resulting in an electrical charge. In the case of strontium, it readily loses two electrons from its outermost shell, forming a positively charged ion, specifically Sr²⁺. This positive charge allows it to interact with negatively charged particles and participate in chemical reactions.
Strontium is the 15th most abundant element in the Earth’s crust, found in minerals such as celestine (strontium sulfate) and strontianite (strontium carbonate). Its presence is widespread across rocks, soils, natural waters, and various foods, making it a ubiquitous element in the environment and biological systems. The chemical behavior of strontium ions is notably similar to that of calcium ions, which influences how it is processed by living organisms.
Diverse Applications
Strontium ions find various practical uses across several fields. In medicine, due to its chemical resemblance to calcium, strontium has been explored for its role in bone health. Strontium ranelate, a compound containing strontium, has been used for treating osteoporosis, helping to support bone density. Strontium is also incorporated into certain toothpastes to help reduce tooth sensitivity.
Beyond medical uses, strontium ions are employed in industrial applications. A use is in pyrotechnics, where strontium compounds produce the vibrant red color seen in fireworks. Historically, strontium was used in the glass of cathode ray tube (CRT) televisions to block X-ray emissions. It also finds use in specialized magnets and in some types of glow-in-the-dark paints due to its luminescent properties. In scientific research, strontium ions have applications in highly precise atomic clocks.
Effects on Human Health
Strontium ions are naturally present in the human body, particularly in bones, where their distribution and metabolism are similar to calcium. This allows strontium to be incorporated into bone tissue. Studies indicate that strontium can influence bone metabolism, increasing bone volume and the number of bone-forming cells while decreasing bone-resorbing cells.
While stable strontium ions have beneficial or neutral effects at environmental exposure levels, it is important to distinguish them from radioactive strontium. Strontium-90 (⁹⁰Sr) is a radioactive isotope that is not naturally occurring but is a byproduct of nuclear fission, such as from nuclear power generation or nuclear weapons testing. Unlike stable strontium, Strontium-90 poses health concerns because it can accumulate in bones, similar to stable strontium, and its radioactivity can potentially increase the risk of certain cancers over time.
Exposure to stable strontium occurs through diet, as it is found in various foods and drinking water. Environmental exposure can also occur through soil and water sources. The body maintains a daily balance of strontium, with intake from food and fluid, and excretion primarily through feces and urine.