Editing Persistent organic pollutant (section)

== Stockholm Convention on Persistent Organic Pollutants ==
[[File:Map of Stockholm Convention on Persistent Organic Pollutants.svg|thumb|275px|State parties to the Stockholm Convention on Persistent Organic Pollutants]]
{{Main|Stockholm Convention on Persistent Organic Pollutants}}

The Stockholm Convention was adopted and put into practice by the [[United Nations Environment Programme]] (UNEP) on May 22, 2001. The UNEP decided that POP regulation needed to be addressed globally for the future. The purpose statement of the agreement is "to protect human health and the environment from persistent organic pollutants." As of 2024, there are 185 countries plus the European Union have ratified the Stockholm Convention.<ref name="UNTC">United Nations Treaty Collection: [https://treaties.un.org/Pages/ViewDetails.aspx?src=IND&mtdsg_no=XXVII-15&chapter=27&clang=_en CHAPTER XXVII – ENVIRONMENT – 15. Stockholm Convention on Persistent Organic Pollutants]</ref> The convention and its participants have recognized the potential human and environmental toxicity of POPs. They recognize that POPs have the potential for long-range transport and bioaccumulation and biomagnification. The convention seeks to study and then judge whether or not a number of chemicals that have been developed with advances in technology and science can be categorized as POPs. The initial meeting in 2001 made a preliminary list, termed the "dirty dozen", of chemicals that are classified as POPs.<ref name=":0" /> As of 2024, the [[United States]] has signed the Stockholm Convention but has not ratified it. There are a handful of other countries that have not ratified the convention but most countries in the world have ratified the convention.<ref name="UNTC" />

=== Compounds on the Stockholm Convention list ===
{{cite-section|date=July 2024}}
In May 1995, the UNEP Governing Council investigated POPs.<ref name="thedirtydozen">{{cite web|title=The Dirty Dozen|url=http://www.unido.org/fileadmin/import/29239_popspresentation.swf|publisher=United Nations Industrial Development Organization|access-date=27 March 2014|archive-date=4 March 2016|archive-url=https://web.archive.org/web/20160304055652/http://www.unido.org/fileadmin/import/29239_popspresentation.swf|url-status=dead}}</ref> Initially the Convention recognized only twelve POPs for their adverse effects on human health and the environment, placing a global ban on these particularly harmful and toxic compounds and requiring its parties to take measures to eliminate or reduce the release of POPs in the environment.<ref name="El-Shahawi, M.S. 2010"/><ref name=":0">{{cite web|url=http://chm.pops.int/Portals/0/Repository/convention_text/UNEP-POPS-COP-CONVTEXT-FULL.English.PDF| title=STOCKHOLM CONVENTION ON PERSISTENT ORGANIC POLLUTANTS| pages=1–43| access-date=27 March 2014}}</ref><ref>{{Cite web |title=Website of the Stockholm Convention |url=http://chm.pops.int/}}</ref>

# '''[[Aldrin]]''', an insecticide used in soils to kill [[termite]]s, [[grasshopper]]s, [[Western corn rootworm]], and others, is also known to kill birds, fish, and humans. Humans are primarily exposed to aldrin through dairy products and animal meats.
# '''[[Chlordane]]''', an insecticide used to control termites and on a range of agricultural crops, is known to be lethal in various species of birds, including mallard ducks, bobwhite quail, and pink shrimp; it is a chemical that remains in the soil with a reported [[half-life]] of one year. Chlordane has been postulated to affect the human immune system and is classified as a possible human [[carcinogen]]. Chlordane air pollution is believed the primary route of human exposure.
# '''[[Dieldrin]]''', a pesticide used to control termites, textile pests, insect-borne diseases and insects living in agricultural soils. In soil and insects, aldrin can be oxidized, resulting in rapid conversion to dieldrin. Dieldrin's half-life is approximately five years. Dieldrin is highly toxic to fish and other aquatic animals, particularly frogs, whose embryos can develop spinal deformities after exposure to low levels. Dieldrin has been linked to [[Parkinson's disease]], [[breast cancer]], and classified as immunotoxic, neurotoxic, with [[Endocrine disruptor|endocrine disrupting]] capacity. Dieldrin residues have been found in air, water, soil, fish, birds, and mammals. Human exposure to dieldrin primarily derives from food.
# '''[[Endrin]]''', an insecticide sprayed on the leaves of crops, and used to control rodents. Animals can metabolize endrin, so fatty tissue accumulation is not an issue, however the chemical has a long half-life in soil for up to 12 years. Endrin is highly toxic to aquatic animals and humans as a [[neurotoxin]]. Human exposure results primarily through food.
# '''[[Heptachlor]]''', a [[pesticide]] primarily used to kill soil insects and termites, along with cotton insects, grasshoppers, other crop pests, and malaria-carrying mosquitoes. Heptachlor, even at very low doses has been associated with the decline of several wild bird populations – [[Canada goose|Canada geese]] and [[American kestrel]]s. In laboratory tests have shown high-dose heptachlor as lethal, with adverse behavioral changes and reduced reproductive success at low-doses, and is classified as a possible human carcinogen. Human exposure primarily results from food.
# '''[[Hexachlorobenzene]] (HCB''') was first introduced in 1945–59 to treat seeds because it can kill [[Fungicide|fungi]] on food crops. HCB-treated seed grain consumption is associated with photosensitive skin lesions, [[colic]], debilitation, and a [[Metabolic syndrome|metabolic disorder]] called porphyria turcica, which can be lethal. Mothers who pass HCB to their infants through the placenta and breast milk had limited reproductive success including infant death. Human exposure is primarily from food.
# '''[[Mirex]]''', an insecticide used against ants and termites or as a [[flame retardant]] in plastics, rubber, and electrical goods. Mirex is one of the most stable and persistent pesticides, with a half-life of up to 10 years.  Mirex is toxic to several plant, fish and [[crustacean]] species, with suggested carcinogenic capacity in humans. Humans are exposed primarily through animal meat, fish, and wild game.
# '''[[Toxaphene]]''', an insecticide used on cotton, cereal, grain, fruits, nuts, and vegetables, as well as for tick and mite control in livestock. Widespread toxaphene use in the US and chemical persistence, with a half-life of up to 12 years in soil, results in residual toxaphene in the environment. Toxaphene is highly toxic to fish, inducing dramatic weight loss and reduced egg viability. Human exposure primarily results from food. While human toxicity to direct toxaphene exposure is low, the compound is classified as a possible human carcinogen.
# '''[[Polychlorinated biphenyls]]''' (PCBs), used as [[Heat-transfer oil|heat exchange fluids]], in [[transformer|electrical transformers]], and [[capacitor]]s, and as additives in paint, carbonless copy paper, and plastics. Persistence varies with degree of [[halogenation]], an estimated half-life of 10 years. PCBs are toxic to fish at high doses, and associated with spawning failure at low doses. Human exposure occurs through food, and is associated with reproductive failure and immune suppression. Immediate effects of PCB exposure include pigmentation of nails and [[mucous membranes]] and swelling of the eyelids, along with fatigue, nausea, and vomiting. Effects are [[Transgenerational epigenetics|transgenerational]], as the chemical can persist in a mother's body for up to 7 years, resulting in developmental delays and behavioral problems in her children. Food contamination has led to large scale PCB exposure.
# [[DDT|'''Dichlorodiphenyltrichloroethane''']] (DDT) is probably the most infamous POP. It was widely used as insecticide during WWII to protect against malaria and typhus. After the war, DDT was used as an agricultural insecticide. In 1962, the American biologist [[Rachel Carson]] published ''[[Silent Spring]]'', describing the impact of DDT spraying on the US environment and human health. DDT's persistence in the soil for up to 10–15 years after application has resulted in widespread and persistent DDT residues throughout the world including the arctic, even though it has been banned or severely restricted in most of the world. DDT is toxic to many organisms including birds where it is detrimental to reproduction due to eggshell thinning. DDT can be detected in foods from all over the world and food-borne DDT remains the greatest source of human exposure. Short-term acute effects of DDT on humans are limited, however long-term exposure has been associated with chronic health effects including increased risk of cancer and diabetes, reduced reproductive success, and neurological disease.
# '''[[Dioxins]]''' are unintentional by-products of high-temperature processes, such as incomplete combustion and pesticide production. Dioxins are typically emitted from the burning of hospital waste, municipal waste, and [[hazardous waste]], along with automobile emissions, peat, coal, and wood. Dioxins have been associated with several adverse effects in humans, including immune and enzyme disorders, [[chloracne]], and are classified as a possible human carcinogen. In laboratory studies of dioxin effects an increase in birth defects and stillbirths, and lethal exposure have been associated with the substances. Food, particularly from animals, is the principal source of human exposure to dioxins. Dioxins were present in [[Agent Orange]], which was used by the United States in chemical warfare against Vietnam and caused devastating multi-generational effects in both Vietnamese and American civilians.
# '''[[Polychlorinated dibenzofurans]]''' are by-products of high-temperature processes, such as incomplete [[combustion]] after [[Incineration|waste incineration]] or in automobiles, pesticide production, and [[polychlorinated biphenyl]] production. Structurally similar to dioxins, the two compounds share toxic effects. Furans persist in the environment and classified as possible human carcinogens. Human exposure to furans primarily results from food, particularly animal products.

=== New POPs on the Stockholm Convention list ===
Since 2001, this list has been expanded to include some [[polycyclic aromatic hydrocarbons]] (PAHs), [[brominated flame retardant]]s, and other compounds. Additions to the initial 2001 Stockholm Convention list are the following POPs:<ref>{{citation | title = Stockholm Convention on Persistent Organic Pollutants (POPs): Text and Annexes | url = https://www.pops.int/Portals/0/download.aspx?d=UNEP-POPS-COP-CONVTEXT-2023.English.pdf | publisher = Secretariat of the Stockholm Convention | date = May 2023 | access-date = 2025-01-27}}.</ref><ref name=":0" />
* [[alpha-Hexachlorocyclohexane|α-Hexachlorocyclohexane]] (α-HCH) and [[beta-Hexachlorocyclohexane|β-Hexachlorocyclohexane]] (β-HCH) are insecticides as well as by-products in the production of [[lindane]]. α-HCH and β-HCH are highly persistent in the water of colder regions. <ref>{{citation | title = Lindane, Alpha-HCH, Beta-HCH factsheet | url = https://www.pops.int/Portals/0/download.aspx?d=UNEP-POPS-NewPOPs-Factsheet-01.02.03-20200226.English.pdf | publisher = Secretariat of the Stockholm Convention | access-date = 2025-01-27}}.</ref> α-HCH and β-HCH have been linked to [[Parkinson's disease|Parkinson's]] and [[Alzheimer's disease]].{{citation needed|date=April 2015}}
* [[Chlordecone]] is primarily used as an agricultural pesticide, related to DDT and Mirex. Chlordecone is toxic to aquatic organisms, and classified as a possible human carcinogen. <ref>{{citation | title = Chlordecone ether factsheet | url = https://www.pops.int/Portals/0/download.aspx?d=UNEP-POPS-NewPOPs-Factsheet-04-20200226.English.pdf | publisher = Secretariat of the Stockholm Convention | access-date = 2025-01-27}}.</ref> Many countries have banned chlordecone sale and use, or intend to destroy stockpiles.
* [[Decabromodiphenyl ether]], a flame retardant, commonly sold as decaBDE, which is added to polymers, textiles, adhesives, coatings and more. In addition to bioaccumulation potential, the Stockholm convention identified decaBDE as affecting human endocrine, reproductive, and nervous systems.<ref>{{citation | title = Decabromodiphenyl ether factsheet | url = https://www.pops.int/Portals/0/download.aspx?d=UNEP-POPS-NewPOPs-Factsheet-05-20200313.English.pdf | publisher = Secretariat of the Stockholm Convention | access-date = 2025-01-27}}.</ref>
* [[Dechlorane plus]] is a flame retardant structurally similar to [[Mirex]]. Added to the Stockholm Convention in 2023, research into human toxicology is ongoing. <ref>{{citation | title = Dechlorane Plus: Candidate POP in Stockholm Convention | url = https://toxicslink.org/publications/factsheet/factsheets-dechlorane-plus | publisher = Toxics Link | date = July 2022 | access-date = 2025-01-27}}.</ref>
* [[Dicofol]] is a pesticide structurally similar to [[DDT]] and is highly toxic to fish, birds, aquatic invertebrates, and algae. Prolonged exposure in humans causes skin irritation.<ref>{{citation | title = Dicofol factsheet | url = https://www.pops.int/Portals/0/download.aspx?d=UNEP-POPS-NewPOPs-Factsheet-06-20200316.English.pdf | publisher = Secretariat of the Stockholm Convention | access-date = 2025-01-27}}.</ref>
* [[Hexabromodiphenyl]] is a flame retardant and possible human carcinogen.  Like the related chemicals hexaBDE, heptaBDE, and octaBDE (see below), hexabromodiphenyl is an endocrine disruptor.  <ref>{{Cite journal |last1=Kumari |first1=K. |last2=Arfin |first2=T. |date=2024 |title=Hexabromobiphenyl (HBB). |url=https://doi.org/10.1007/978-3-031-50996-4_14 |journal=Pollutants of Global Concern. Emerging Contaminants and Associated Treatment Technologies. |language=en |doi=10.1007/978-3-031-50996-4_14|url-access=subscription }}</ref>
* [[Hexabromocyclododecane]] is a flame retardant predominately used in foams and textiles that is highly toxic to aquatic organisms.  Human toxicology studies are ongoing, but it shows neuroendocrine disruption and developmental toxicity in animal studies.<ref>{{citation | title = Hexabromocyclododecane factsheet | url = https://www.pops.int/Portals/0/download.aspx?d=UNEP-POPS-NewPOPs-Factsheet-08-20200226.English.pdf | publisher = Secretariat of the Stockholm Convention | access-date = 2025-01-27}}.</ref>
* [[Hexabromodiphenyl ether]] (hexaBDE) and [[heptabromodiphenyl ether]] (heptaBDE) are main components of the flame retardant [[octabromodiphenyl ether]] (octaBDE). Commercial octaBDE is highly persistent in the environment, whose only degradation pathway is through debromination and the production of [[Bromodiphenylmethane|bromodiphenyl ethers]], which themselves can be toxic.<ref>{{citation | title = Hexabromobiphenyl ether and heptabromodiphenyl ether factsheet | url = https://www.pops.int/Portals/0/download.aspx?d=UNEP-POPS-NewPOPs-Factsheet-09-20200226.English.pdf | publisher = Secretariat of the Stockholm Convention | access-date = 2025-01-27}}.</ref>
* [[Hexachlorobutadiene]] (HCBD) is a byproduct of the production of other chlorinated compounds.  HCBD is a possible human carcinogen and causes renal damage.<ref>{{citation | title = Hexachlorobutadiene factsheet | url = https://www.pops.int/Portals/0/download.aspx?d=UNEP-POPS-NewPOPs-Factsheet-10-20200226.English.pdf | publisher = Secretariat of the Stockholm Convention | access-date = 2025-01-27}}.</ref>
* [[Lindane]] (γ-hexachlorocyclohexane), a pesticide used as a broad spectrum insecticide for seed, soil, leaf, tree and wood treatment, and against [[ectoparasite]]s in animals and humans (head lice and scabies). Lindane undergoes rapid [[biomagnification]] and is [[Immunotoxin|immunotoxic]], [[Neurotoxicity|neurotoxic]], [[carcinogenic]], linked to liver and kidney damage as well as adverse reproductive and developmental effects in various laboratory animals. Production of lindane unintentionally produces two other POPs α-HCH and β-HCH.<ref>{{Cite journal |last1=Vijgen |first1=John |last2=de Borst |first2=Bram |last3=Weber |first3=Roland |last4=Stobiecki |first4=Tomasz |last5=Forter |first5=Martin |date=2019 |title=HCH and lindane contaminated sites: European and global need for a permanent solution for a long-time neglected issue |journal=Environmental Pollution |language=en |volume=248 |pages=696–705 |doi=10.1016/j.envpol.2019.02.029|pmid=30849587 |bibcode=2019EPoll.248..696V }}</ref>
* [[Methoxychlor]] is a pesticide structurally similar to DDT.  In addition to persistence, ecological mobility, and bioaccumulation risk, it also is a human endocrine disruptor.<ref>{{citation | title = Methoxychlor factsheet | url = https://www.pops.int/Portals/0/download.aspx?d=UNEP-POPS-NewPOPs-Factsheet-19-20240726.English.pdf | publisher = Secretariat of the Stockholm Convention | access-date = 2025-01-27}}.</ref>
* [[Pentachlorobenzene]] (PeCB), is a pesticide and unintentional byproduct. PeCB has also been used in PCB products, dyestuff carriers, as a fungicide, a flame retardant, and a chemical intermediate. This compound is moderately toxic to humans, whilst being highly toxic to aquatic organisms. <ref>{{citation | title = Pentachlorobenzene factsheet | url = https://www.pops.int/Portals/0/download.aspx?d=UNEP-POPS-NewPOPs-Factsheet-11-20200226.English.pdf | publisher = Secretariat of the Stockholm Convention | access-date = 2025-01-27}}.</ref>
* [[Perfluorooctanesulfonic acid]] (PFOS) and related compounds are extremely persistent and readily [[Biomagnification|biomagnify]].  
* [[Endosulfan]]s are a group of chlorinated insecticides used to control pests on crops such coffee, cotton, rice and sorghum and soybeans, tsetse flies, ectoparasites of cattle. They are used as a [[Wood preservation|wood preservative]]. Global use and manufacturing of endosulfan has been banned under the Stockholm convention in 2011, although many countries had previously banned or introduced phase-outs of the chemical when the ban was announced. Toxic to humans and aquatic and terrestrial organisms, linked to congenital physical disorders, mental retardation, and death. Endosulfans' negative health effects are primarily liked to its endocrine disrupting capacity acting as an [[antiandrogen]].
* [[Tetrabromodiphenyl ether]] (tetraBDE) and pentabromodiphenyl ether (pentaBDE) are industrial chemicals and the main components of commercial pentabromodiphenyl ether (pentaBDE). This pair of molecules have been detected in humans in all regions of the world.