Editing Radioactive waste (section)

=== Pharmacokinetics ===
Exposure to radioactive waste may cause health impacts due to ionizing radiation exposure. In humans, a dose of 1 [[sievert]] carries a 5.5% risk of developing cancer,<ref name="ICRP103">{{cite journal |title=The 2007 Recommendations of the International Commission on Radiological Protection |journal=Annals of the ICRP |year=2007 |volume=37 |series=ICRP publication 103 |issue=2–4 |url=http://www.icrp.org/publication.asp?id=ICRP%20Publication%20103 |isbn=978-0-7020-3048-2 |url-status=live |archive-url=https://web.archive.org/web/20121116084754/http://www.icrp.org/publication.asp?id=ICRP+Publication+103 |archive-date=2012-11-16}}</ref> and regulatory agencies [[linear no-threshold model|assume the risk is linearly proportional to dose]] even for low doses. Ionizing radiation can cause deletions in chromosomes.<ref>Gofman, John W. ''Radiation and human health''. San Francisco, California: Sierra Club Books, 1981, p. 787.</ref> If a developing organism such as a [[fetus]] is irradiated, it is possible a [[birth defect]] may be induced, but it is unlikely this defect will be in a [[gamete]] or a gamete-forming [[cell (biology)|cell]]. The incidence of radiation-induced mutations in humans is small, as in most mammals, because of natural cellular-repair mechanisms, many just now coming to light. These mechanisms range from DNA, [[mRNA]] and protein repair, to internal lysosomic digestion of defective proteins, and even induced cell suicide—apoptosis<ref>Sancar, A. et al ''Molecular mechanisms of mammalian DNA repair and the DNA damage checkpoints''. Washington, D.C.: National Institutes of Health PubMed.gov, 2004.</ref>

Depending on the decay mode and the [[pharmacokinetics]] [[radiopharmacology|of an element]] (how the body processes it and how quickly), the threat due to exposure to a given activity of a [[radioisotope]] will differ. For instance, [[iodine-131]] is a short-lived [[beta decay|beta]] and [[gamma decay|gamma]] emitter, but because it concentrates in the [[thyroid]] gland, it is more able to cause injury than [[caesium]]-137 which, being [[water soluble]], is rapidly excreted through urine. In a similar way, the [[alpha decay|alpha]] emitting actinides and [[radium]] are considered very harmful as they tend to have long [[Biological half-life|biological half-lives]] and their radiation has a high [[relative biological effectiveness]], making it far more damaging to tissues per amount of energy deposited. Because of such differences, the rules determining biological injury differ widely according to the radioisotope, time of exposure, and sometimes also the nature of the chemical compound which contains the radioisotope.