Editing Strontium (section)

===Isotopes===
{{main|Isotopes of strontium}}

Natural strontium is a mixture of four stable [[isotope]]s: <sup>84</sup>Sr, <sup>86</sup>Sr, <sup>87</sup>Sr, and <sup>88</sup>Sr.<ref name="CRC" /> On these isotopes, <sup>88</sup>Sr is the most abundant, makes up about 82.6% of all natural strontium, though the abundance varies due to the production of [[radiogenic]] <sup>87</sup>Sr as the daughter of long-lived [[beta-decay]]ing <sup>87</sup>[[Isotopes of rubidium|Rb]].<ref>Greenwood and Earnshaw, p. 19</ref> This is the basis of [[rubidium–strontium dating]]. Of the unstable isotopes, the primary decay mode of the isotopes lighter than <sup>85</sup>Sr is [[electron capture]] or [[positron emission]] to isotopes of rubidium, and that of the isotopes heavier than <sup>88</sup>Sr is [[electron emission]] to isotopes of [[yttrium]]. Of special note are [[strontium-89|<sup>89</sup>Sr]] and [[strontium-90|<sup>90</sup>Sr]]. The former has a [[half-life]] of 50.6&nbsp;days and is used to treat [[bone cancer]] due to strontium's chemical similarity and hence ability to replace calcium.<ref name="HalperinPerez2008">{{cite book|last1=Halperin|first1=Edward C.|last2=Perez|first2=Carlos A.|last3=Brady|first3=Luther W.|title=Perez and Brady's principles and practice of radiation oncology|url=https://books.google.com/books?id=NyeE6-aKnSYC&pg=PA1997|access-date=19 July 2011|year=2008|publisher=Lippincott Williams & Wilkins|isbn=978-0-7817-6369-1|pages=1997–}}</ref><ref name="BaumanCharette2005">{{cite journal|last1=Bauman|first1=Glenn|last2=Charette|first2=Manya|last3=Reid|first3=Robert|last4=Sathya|first4=Jinka|title=Radiopharmaceuticals for the palliation of painful bone metastases – a systematic review|journal=Radiotherapy and Oncology|volume=75|issue=3|year=2005|pages=258.E1–258.E13|doi=10.1016/j.radonc.2005.03.003|pmid=16299924}}</ref> While <sup>90</sup>Sr (half-life 28.90&nbsp;years) has been used similarly, it is also an isotope of concern in [[nuclear fallout|fallout]] from [[nuclear weapons]] and [[nuclear accidents]] due to its production as a [[fission product]]. Its presence in bones can cause bone cancer, cancer of nearby tissues, and [[leukemia]].<ref name="EPA">{{cite web |url=http://www.epa.gov/rpdweb00/radionuclides/strontium.html#environment |title=Strontium {{pipe}} Radiation Protection {{pipe}} US EPA |publisher=[[United States Environmental Protection Agency|EPA]] |date=24 April 2012 |access-date=18 June 2012}}</ref> The [[Chernobyl accident|1986 Chernobyl nuclear accident]] contaminated about 30,000&nbsp;km<sup>2</sup> with greater than 10&nbsp;kBq/m<sup>2</sup> with <sup>90</sup>Sr, which accounts for about 5% of the <sup>90</sup>Sr which was in the reactor core.<ref name="OECD02-Ch1">{{cite web| url=https://www.oecd-nea.org/rp/reports/2003/nea3508-chernobyl.pdf |title=Chernobyl: Assessment of Radiological and Health Impact, 2002 update; Chapter I – The site and accident sequence |publisher=OECD-NEA | year=2002 |access-date=3 June 2015}}</ref>