Editing Persistent organic pollutant (section)

==Consequences of persistence==
POPs typically are halogenated organic compounds (see lists below) and as such exhibit high [[Lipophilicity|lipid solubility]].  For this reason, they [[bioaccumulation|bioaccumulate]] in [[Adipose tissue|fatty tissues]].<ref>{{Cite journal |last1=Leonards |first1=P. E. G. |last2=Broekhuizen |first2=S. |last3=de Voogt |first3=P. |last4=Van Straalen |first4=N. M. |last5=Brinkman |first5=U. A.Th. |last6=Cofino |first6=W. P. |last7=van Hattum |first7=B. |date=1998-11-01 |title=Studies of Bioaccumulation and Biotransformation of PCBs in Mustelids Based on Concentration and Congener Patterns in Predators and Preys |url=https://doi.org/10.1007/s002449900428 |journal=Archives of Environmental Contamination and Toxicology |language=en |volume=35 |issue=4 |pages=654–665 |doi=10.1007/s002449900428 |pmid=9776784 |bibcode=1998ArECT..35..654L |issn=1432-0703|url-access=subscription }}</ref><ref>{{Cite journal |last1=Elliott |first1=Kyle Hamish |last2=Cesh |first2=Lillian S. |last3=Dooley |first3=Jessica A. |last4=Letcher |first4=Robert J. |last5=Elliott |first5=John E. |date=2009-06-01 |title=PCBs and DDE, but not PBDEs, increase with trophic level and marine input in nestling bald eagles |url=https://www.sciencedirect.com/science/article/pii/S0048969709002058 |journal=Science of the Total Environment |series=Thematic Issue - BioMicroWorld Conference |volume=407 |issue=12 |pages=3867–3875 |doi=10.1016/j.scitotenv.2009.02.027 |pmid=19339036 |bibcode=2009ScTEn.407.3867E |issn=0048-9697|url-access=subscription }}</ref><ref>{{Cite journal |last1=Gobas |first1=Frank A.P.C. |last2=Arnot |first2=Jon A. |date=2010-05-14 |title=Food web bioaccumulation model for polychlorinated biphenyls in San Francisco Bay, California, USA |url=https://setac.onlinelibrary.wiley.com/doi/10.1002/etc.164 |journal=Environmental Toxicology and Chemistry |language=en |volume=29 |issue=6 |pages=1385–1395 |doi=10.1002/etc.164 |pmid=20821583 |bibcode=2010EnvTC..29.1385G |issn=0730-7268|url-access=subscription }}</ref><ref>{{Cite journal |last1=Huang |first1=Andrew C. |last2=Nelson |first2=Cait |last3=Elliott |first3=John E. |last4=Guertin |first4=Daniel A. |last5=Ritland |first5=Carol |last6=Drouillard |first6=Ken |last7=Cheng |first7=Kimberly M. |last8=Schwantje |first8=Helen M. |date=2018-07-01 |title=River otters (Lontra canadensis) "trapped" in a coastal environment contaminated with persistent organic pollutants: Demographic and physiological consequences |journal=Environmental Pollution |volume=238 |pages=306–316 |doi=10.1016/j.envpol.2018.03.035 |pmid=29573713 |bibcode=2018EPoll.238..306H |issn=0269-7491|doi-access=free }}</ref> [[Halogenated]] compounds also exhibit great [[Chemical stability|stability]] reflecting the nonreactivity of C-Cl bonds toward [[hydrolysis]] and [[Photodissociation|photolytic degradation]]. The stability and lipophilicity of organic compounds often correlates with their halogen content, thus polyhalogenated organic compounds are of particular concern.<ref name="ritter" /> They exert their negative effects on the environment through two processes: long range transport, which allows them to travel far from their source, and bioaccumulation, which reconcentrates these chemical compounds to potentially dangerous levels.<ref name="Walker, C.H. 2001">Walker, C.H., "Organic Pollutants: An Ecotoxicological Perspective" (2001).</ref> Compounds that make up POPs are also classed as [[Persistent, bioaccumulative and toxic substances|PBTs]] (persistent, bioaccumulative and toxic) or TOMPs (toxic organic micro pollutants).<ref>{{Cite web|date=2013-08-20|title=Persistent, Bioaccumulative and Toxic Chemicals (PBTs)|url=https://saferchemicals.org/get-the-facts/toxic-chemicals/persistent-bioaccumulative-and-toxic-chemicals-pbts/|access-date=2022-02-01|website=Safer Chemicals Healthy Families|language=en-US}}</ref>

=== Long-range transport ===
{{See also|Global distillation}}
POPs enter the [[gas]] phase under certain environmental temperatures and [[Volatility (chemistry)|volatilize]] from [[soil]]s, [[vegetation]], and [[bodies of water]] into the [[atmosphere]], resisting breakdown reactions in the air, to travel long distances before being re-deposited.<ref name="Kelly, B.C. 2007">{{cite journal |last1=Kelly |first1=Barry C. |last2=Ikonomou |first2=Michael G. |last3=Blair |first3=Joel D. |last4=Morin |first4=Anne E. |last5=Gobas |first5=Frank A. P. C. |title=Food Web–Specific Biomagnification of Persistent Organic Pollutants |journal=Science |date=13 July 2007 |volume=317 |issue=5835 |pages=236–239 |doi=10.1126/science.1138275 |pmid=17626882 |bibcode=2007Sci...317..236K |s2cid=52835862 }}</ref> This results in accumulation of POPs in areas far from where they were used or emitted, specifically environments where POPs have never been introduced such as [[Antarctica]], and the [[Arctic Circle]].<ref>{{cite journal | author1 = Beyer A.| author2=Mackay D.| author3=Matthies M.| author4=Wania F.| author5=Webster E. | year = 2000 | title = Assessing Long-Range Transport Potential of Persistent Organic Pollutants | journal = Environmental Science & Technology | volume = 34 | issue = 4| pages = 699–703 | doi = 10.1021/es990207w | bibcode = 2000EnST...34..699B }}</ref> POPs can be present as vapors in the atmosphere or bound to the surface of solid [[particulates|particles]] ([[aerosol]]s). A determining factor for the long-range transport is the fraction of a POP that is adsorbed on aerosols. In adsorbed form it is – as opposed to the gas phase – protected from photo-oxidation, i.e. direct [[photolysis]] as well as oxidation by [[OH radical]]s or ozone.<ref>{{Cite journal|last1=Koester|first1=Carolyn J.|last2=Hites|first2=Ronald A.|date=March 1992|title=Photodegradation of polychlorinated dioxins and dibenzofurans adsorbed to fly ash|journal=Environmental Science & Technology|language=en|volume=26|issue=3|pages=502–507|doi=10.1021/es00027a008|bibcode=1992EnST...26..502K|issn=0013-936X}}</ref><ref>{{Cite journal|last1=Raff|first1=Jonathan D.|last2=Hites|first2=Ronald A.|date=October 2007|title=Deposition versus Photochemical Removal of PBDEs from Lake Superior Air|journal=Environmental Science & Technology|language=en|volume=41|issue=19|pages=6725–6731|doi=10.1021/es070789e|pmid=17969687|bibcode=2007EnST...41.6725R|issn=0013-936X}}</ref>

POPs have low solubility in water but are easily captured by solid particles, and are soluble in organic fluids ([[oil]]s, [[fat]]s, and [[liquid fuel]]s). POPs are not easily degraded in the environment due to their stability and low [[Chemical decomposition|decomposition]] rates. Due to this capacity for long-range transport, POP environmental contamination is extensive, even in areas where POPs have never been used, and will remain in these environments years after restrictions implemented due to their resistance to degradation.<ref name="ritter" /><ref name="Wania, F. 1996">{{cite journal | author = Wania F., Mackay D. | year = 1996 | title = Tracking the Distribution of Persistent Organic Pollutants | journal = Environmental Science & Technology | volume = 30 | issue = 9| pages = 390A–396A | doi = 10.1021/es962399q | pmid = 21649427 }}</ref><ref>{{cite thesis|last=Astoviza|first=Malena J.|title=Evaluación de la distribución de contaminantes orgánicos persistentes (COPs) en aire en la zona de la cuenca del Plata mediante muestreadores pasivos artificiales|date=15 April 2014|pages=160|publisher=Universidad Nacional de La Plata |doi=10.35537/10915/34729 |language=es|url=http://sedici.unlp.edu.ar/handle/10915/34729|access-date=16 April 2014|type=Tesis |doi-access=free}}</ref>

=== Bioaccumulation ===
[[Bioaccumulation]] of POPs is typically associated with the compounds high lipid solubility and ability to accumulate in the [[adipose tissue|fatty tissues]] of living organisms including human tissues for long periods of time.<ref name="Wania, F. 1996"/><ref name="Vallack, H.W. 1998">{{cite journal |last1=Vallack |first1=Harry W. |last2=Bakker |first2=Dick J. |last3=Brandt |first3=Ingvar |last4=Broström-Lundén |first4=Eva |last5=Brouwer |first5=Abraham |last6=Bull |first6=Keith R. |last7=Gough |first7=Clair |last8=Guardans |first8=Ramon |last9=Holoubek |first9=Ivan |last10=Jansson |first10=Bo |last11=Koch |first11=Rainer |last12=Kuylenstierna |first12=Johan |last13=Lecloux |first13=André |last14=Mackay |first14=Donald |last15=McCutcheon |first15=Patrick |last16=Mocarelli |first16=Paolo |last17=Taalman |first17=Rob D.F. |title=Controlling persistent organic pollutants–what next? |journal=Environmental Toxicology and Pharmacology |date=November 1998 |volume=6 |issue=3 |pages=143–175 |doi=10.1016/S1382-6689(98)00036-2| pmid = 21781891|bibcode=1998EnvTP...6..143V }}</ref> Persistent chemicals tend to have higher concentrations and are eliminated more slowly. Dietary accumulation or bioaccumulation is another hallmark characteristic of POPs, as POPs move up the food chain, they increase in concentration as they are processed and metabolized in certain tissues of organisms. The natural capacity for animals [[Human gastrointestinal tract|gastrointestinal tract]] to concentrate ingested chemicals, along with poorly [[Metabolism|metabolized]] and [[hydrophobic]] nature of POPs, makes such compounds highly susceptible to bioaccumulation.<ref>{{cite journal |last1=Yu |first1=George W. |last2=Laseter |first2=John |last3=Mylander |first3=Charles |title=Persistent Organic Pollutants in Serum and Several Different Fat Compartments in Humans |journal=Journal of Environmental and Public Health |date=2011 |volume=2011 |page=417980 |doi=10.1155/2011/417980 |pmid= 21647350 |pmc=3103883 |doi-access=free}}</ref> Thus POPs not only persist in the environment, but also as they are taken in by animals they bioaccumulate, increasing their concentration and toxicity in the environment.<ref name="Kelly, B.C. 2007"/><ref>{{cite journal |last1=Lohmann |first1=Rainer |last2=Breivik |first2=Knut |last3=Dachs |first3=Jordi |last4=Muir |first4=Derek |title=Global fate of POPs: Current and future research directions |journal=Environmental Pollution |date=November 2007 |volume=150 |issue=1 |pages=150–165 |doi=10.1016/j.envpol.2007.06.051 |pmid=17698265|bibcode=2007EPoll.150..150L }}</ref> This increase in concentration is called biomagnification, which is where organisms higher up in the food chain have a greater accumulation of POPs.<ref>{{Cite web|last=US EPA|first=OITA|date=2014-04-02|title=Persistent Organic Pollutants: A Global Issue, A Global Response|url=https://www.epa.gov/international-cooperation/persistent-organic-pollutants-global-issue-global-response|access-date=2022-02-01|website=www.epa.gov|language=en}}</ref> Bioaccumulation and long-range transport are the reason why POPs can accumulate in organisms like whales, even in remote areas like Antarctica.<ref>{{Cite journal|last1=Remili|first1=Anaïs|last2=Gallego|first2=Pierre|last3=Pinzone|first3=Marianna|last4=Castro|first4=Cristina|last5=Jauniaux|first5=Thierry|last6=Garigliany|first6=Mutien-Marie|last7=Malarvannan|first7=Govindan|last8=Covaci|first8=Adrian|last9=Das|first9=Krishna|date=2020-12-01|title=Humpback whales (Megaptera novaeangliae) breeding off Mozambique and Ecuador show geographic variation of persistent organic pollutants and isotopic niches|url=http://www.sciencedirect.com/science/article/pii/S0269749120362631|journal=Environmental Pollution|language=en|volume=267|pages=115575|doi=10.1016/j.envpol.2020.115575|pmid=33254700|bibcode=2020EPoll.26715575R |hdl=10067/1744230151162165141 |s2cid=225008427 |issn=0269-7491|hdl-access=free}}</ref>