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-{{otheruses|Contamination (disambiguation)}}
-'''Contamination''' is the presence of a minor and unwanted constituent ([[contaminant]]) in [[material]], [[physical body]],  [[natural environment]], at a [[workplace]], etc.
-==Specifics==
-"Contamination" also has more specific meanings in science: motherfucker
-*In [[chemistry]], the term usually describes a single constituent, but in specialized fields the term can also mean chemical mixtures, even up to the level of cellular materials.
-All chemicals contain some level of contamination.  Contamination may be recognized or not and may become an issue if the contaminated chemical is mixed with other chemicals or mixtures and causes additional chemical reactions.  The additional chemical reactions can sometimes be beneficial, in which case the label ‘contaminant’ is replaced with [[reactant]] or [[catalyst]].  If the additional reactions are detrimental, other terms are often applied such as [[toxin]], [[poison]] or [[pollutant]] depending on the chemistry involved.  A major fraction of chemistry is involved with identifying, isolating, and studying contaminants.
-*In [[environmental chemistry]] the term is in some cases is virtually equivalent to [[pollution]], where the main interest is the harm done on a large scale to humans or to organisms or environments that are important to humans.
-*In [[radiation protection]] the [[radioactive contamination]] is radioactive substances on surfaces, or within solids, liquids or gases (including the human body), where their presence is unintended or undesirable, or the process giving rise to their presence in such places<ref>{{cite book |title=IAEA Safety Glossary: Terminology Used in Nuclear Safety and Radiation Protection |last1=International Atomic Energy Agency |authorlink= |year=2007 |publisher=IAEA |location=Vienna |isbn=92–0–100707–8 |pages= |url=http://www-pub.iaea.org/MTCD/publications/PDF/Pub1290_web.pdf |accessdate=}}</ref>,<ref>{{cite book |title= Programmes and Systems for Source and Environmental Radiation Monitoring.  Safety Reports Series No.  64.  |last1=International Atomic Energy Agency |authorlink= |year=2010 |publisher=IAEA |location=Vienna |isbn=978-92-0-112409-8 |pages=234 |url=http://www-pub.iaea.org/mtcd/publications/PubDetails.asp?pubId=8242 |accessdate=}}</ref>.
-: Also used less formally to refer to a quantity, namely the [[activity]] on a surface (or on a unit area of a surface).
-:Contamination does not include residual [[radioactive material]] remaining at a site after the completion of [[decommissioning]].
-:The term [[radioactive contamination]] may have a connotation that is not intended.
-:The term [[radioactive contamination]] refers only to the presence of [[radioactivity]], and gives no indication of the magnitude of the hazard involved.
-'''See also''' [[Environmental monitoring]], [[Radiation monitoring]]
-*In [[food chemistry]] and [[medicinal chemistry]], the term "contamination" is used to describe harmful intrusions, such as the presence of [[toxin]]s or [[pathogen]]s in food or medicinal drugs.
-*In [[forensic science]], a contaminant can be complex materials such as hair or skin particles arising from sources not related to the ongoing investigation.
-*In the [[biology | biological sciences]] accidental introduction of "foreign" material ('contamination') can seriously distort the results of experiments where small samples are used. In cases where the contaminant is a living microorganism, it can often multiply and take over the experiment, especially cultures, and render them useless.
-*In [[geology]] and especially [[geochemistry]], it can have similar effects where even a few grains of "modern" dust can distort results of sophisticated experiments.
-*the term "contamination" is sometimes used to describe accidental transfers of organisms from one natural environment to another.
-*it has even been used in the "Directed [[panspermia]]" hypothesis about the origin of life on Earth, which suggests that visiting aliens accidentally infected the planet with [[microbe]]s from their own world.<ref>{{Cite journal
-| last = Crick | first =  F. H. | last2 = Orgel | first2 = L. E.| title = Directed Panspermia
-| journal = Icarus | volume = 19 | pages =  341–348 | year = 1973| doi = 10.1016/0019-1035(73)90110-3
-| postscript = <!-- Bot inserted parameter. Either remove it; or change its value to "." for the cite to end in a ".", as necessary. -->{{inconsistent citations}}}} </ref>
-==Also see==
-*[[Forensic science]]
-*[[Forensic engineering]]
-==References==
-{{reflist}}
-[[Category:Environmental science]]
-[[Category:Geologic formations]]
-[[Category:Geochemistry]]
-[[de:Kontamination]]
-[[ja:コンタミネーション]]
-[[tl:Kontaminasyon]]
-[[ru:Загрязнение]]