Persistent Organic Pollutants (POPs) are organic chemical substances, that is, they are carbon-based. They possess a particular combination of physical and chemical properties such that, once released into the environment, they:
As a result of releases to the environment over the past several decades due especially to human activities, POPs are now widely distributed over large regions (including those where POPs have never been used) and, in some cases, they are found around the globe. This extensive contamination of environmental media and living organisms includes many foodstuffs and has resulted in the sustained exposure of many species, including humans, for periods of time that span generations, resulting in both acute and chronic toxic effects.
In addition, POPs concentrate in living organisms through another process called bioaccumulation. Though not soluble in water, POPs are readily absorbed in fatty tissue, where concentrations can become magnified by up to 70,000 times the background levels. Fish, predatory birds, mammals, and humans are high up the food chain and so absorb the greatest concentrations. When they travel, the POPs travel with them. As a result of these two processes, POPs can be found in people and animals living in regions such as the Arctic, thousands of kilometers from any major POPs source.
Specific effects of POPs can include cancer, allergies and hypersensitivity, damage to the central and peripheral nervous systems, reproductive disorders, and disruption of the immune system. Some POPs are also considered to be endocrine disrupters, which, by altering the hormonal system, can damage the reproductive and immune systems of exposed individuals as well as their offspring; they can also have developmental and carcinogenic effects.
IPEN videos on POPs are available in the media section.
Initially, twelve POPs have been recognized as causing adverse effects on humans and the ecosystem and these can be placed in 3 categories:
At its fourth meeting held from 4 to 8 May 2009, the Conference of the Parties (COP), by decisions SC-4/10 to SC-4/18, adopted amendments to Annexes A (elimination), B (restriction) and C (unintentional production) of the Stockholm Convention to list nine additional chemicals as persistent organic pollutants.
The chemicals targeted by the Stockholm Convention are listed in the annexes of the convention text:
Parties must take measures to eliminate the production and use of the chemicals listed under Annex A. Specific exemptions for use or production are listed in the Annex and apply only to Parties that register for them.
Parties must take measures to restrict the production and use of the chemicals listed under Annex B in light of any applicable acceptable purposes and/or specific exemptions listed in the Annex.
Parties must take measures to reduce the unintentional releases of chemicals listed under Annex C with the goal of continuing minimization and, where feasible, ultimate elimination.
Amy Party may submit proposal for listing a new chemical in Annex A, B, or C of the Convention. The POPs Review Committe evaluates the proposals and makes recommendation to the Conference of the Parties on such listing. Currently following chemicals are under review:
More information about chemicals under review
Listed under Annex A without specific exemptions (decision SC-4/12)
Risk profile (PDF)Risk management evaluation (PDF)
Chlordecone is chemically related to Mirex, a pesticide listed in Annex A of the Convention.
CAS No: 143-50-0 Trade name: Kepone® and GC-1189
Chlordecone is a synthetic chlorinated organic compound, which was mainly used as an agricultural pesticide. It was first produced in 1951 and introduced commercially in 1958. Currently, no use or production of the chemical is reported.
Chlordecone is highly persistent in the environment, has a high potential for bioaccumulation and biomagnification and based on physico-chemical properties and modelling data, chlordecone can be transported for long distances. It is classified as a possible human carcinogen and is very toxic to aquatic organisms.
Alternatives to chlordecone exist and can be implemented inexpensively. Many countries have already banned its sale and use. The main objective to phase out chlordecone would be to identify and manage obsolete stockpiles and wastes.
Listed under Annex A without specific exemptions (decision SC-4/13)
Hexabromobiphenyl belongs to the group of polybrominated biphenyls, which are brominated hydrocarbons formed by substituting hydrogen with bromine in biphenyl.
CAS No: 36355-01-8 Trade name: FireMaster BP-6 and FireMaster FF-1
Hexabromobiphenyl is an industrial chemical that has been used as a flame retardant, mainly in the 1970s. According to available information, hexabromobiphenyl is no longer produced or used in most countries.
The chemical is highly persistent in the environment, highly bioaccumulative and has a strong possibility for long-range environmental transport. As hexabromobiphenyl is classified as a possible human carcinogen and has other chronic toxic effects, the Committee recommended its listing as a POP.
Alternatives are available for all uses of hexabromobiphenyl, so prohibiting its use and production is feasible and inexpensive. This chemical is already subject to several national and international regulations, restricting its use and production.
Listed under Annex A with a specific exemption for use as articles containing these chemicals for recycling in accordance with the provision in Part IV of Annex A (decision SC-4/14)
Hexabromodiphenyl ether and heptabromodiphenyl ether are the main components of commercial octabromodiphenyl ether.
CAS No: 68631-49-2 CAS No: 207122-15-4 CAS No: 446255-22-7 CAS No: 207122-16-5
Commercial mixture of octaBDE is highly persistent, has a high potential for bioaccumulation and food-web biomagnification, as well as for long-range transport. The only degradation pathway is through debromination and producing other bromodiphenyl ethers.
Alternatives generally exist and there is no information about any current production. However, it is reported that many articles in use still contain these chemicals.
Polybromodiphenyl ethers can be subject to debromination, i.e. the replacement of bromine on the aromatic ring with hydrogen.
Higher bromodiphenyl ether congeners may be converted to lower, and possibly more toxic, congeners. The higher congeners might therefore be precursors to the tetraBDE, pentaBDE, hexaBDE, or heptaBDE.
Listed under Annex A without specific exemptions (decision SC-4/10)
alpha hexachlorocyclohexane CAS No: 319-84-6
Although the intentional use of alpha-HCH as an insecticide was phased out years ago, this chemical is still produced as unintentional by-product of lindane. For each ton of lindane produced, around 6-10 tons of the other isomers including alpha- and beta-HCH are created. Large stockpiles of alpha- and beta-HCH are therefore present in the environment.
Alpha-HCH is highly persistent in water in colder regions and may bioaccumulate and biomagnify in biota and arctic food webs. This chemical is subject to long-range transport, is classified as potentially carcinogenic to humans and adversely affects wildlife and human health in contaminated regions.
Today, alpha-HCH is only produced unintentionally during the production of lindane. Releases also occur from stockpiles and contaminated sites.
Listed under Annex A without specific exemptions (decision SC-4/11)
beta hexachlorocyclohexane CAS No: 319-85-7
Although the intentional use of beta-HCH as an insecticide was phased out years ago, this chemical is still produced as unintentional by-product of lindane. For each ton of lindane produced, around 6-10 tons of the other isomers including alpha- and beta-HCH are created. Large stockpiles of alpha- and beta-HCH are therefore present in the environment.
Beta-HCH is highly persistent in water in colder regions and may bioaccumulate and biomagnify in biota and arctic food webs. This chemical is subject to long-range transport, is classified as potentially carcinogenic to humans and adversely affects wildlife and human health in contaminated regions.
Today, beta-HCH is only produced unintentionally during the production of lindane. Releases also occur from stockpiles and contaminated sites.
Listed under Annex A with a specific exemption for use as a human health pharmaceutical for control of head lice and scabies as second line treatment (decision SC-4/15)
Lindane is the common name for the gamma isomer of hexachlorocyclohexane (HCH). Technical HCH is an isomeric mixture that contains mainly five forms, namely alpha-, beta-, gamma-, delta- and epsilon-HCH.
Lindane (gamma-HCH) CAS No: 58-89-9
Lindane has been used as a broad-spectrum insecticide for seed and soil treatment, foliar applications, tree and wood treatment and against ectoparasites in both veterinary and human applications. The production of lindane has decreased rapidly in the last few years and only few countries are still known to produce lindane.
Lindane is persistent, bioaccumulates easily in the food chain and bioconcentrates rapidly. There is evidence for long-range transport and toxic effects (immunotoxic, reproductive and developmental effects) in laboratory animals and aquatic organisms.
Alternatives for lindane are generally available, except for use as a human health pharmaceutical to control head lice and scabies. Regulations on the production, use and monitoring of lindane already exist in several countries.
Listed under Annex A without specific exemptions and under Annex C (decision SC-4/16)
Risk profile (PDF), addendum to the risk profile (PDF)Risk management evaluation (PDF)
PeCB belongs to a group of chlorobenzenes that are characterized by a benzene ring in which the hydrogen atoms are substituted by one or more chlorines.
CAS No: 608-93-5
PeCB was used in PCB products, in dyestuff carriers, as a fungicide, a flame retardant and as a chemical intermediate e.g. previously for the production of quintozene. PeCB might still be used as an intermediate. PeCB is also produced unintentionally during combustion, thermal and industrial processes. It also present as impurities in products such as solvents or pesticides.
PeCB is persistent in the environment, highly bioaccumulative and has a potential for long-range environmental transport. It is moderately toxic to humans and very toxic to aquatic organisms.
The production of PeCB ceased some decades ago in the main producer countries as efficient and cost-effective alternatives are available. Applying Best Available Techniques and Best Environmental Practices would significantly reduce the unintentional production of PeCB.
Listed under Annex A with a specific exemption for use as articles containing these chemicals for recycling in accordance with the provision in Part IV of Annex A (decision SC-4/18)
Tetrabromodiphenyl ether and pentabromodiphenyl ether are the main components of commercial pentabromodiphenyl ether.
CAS No: 40088-47-9 CAS No: 32534-81-9
Commercial mixture of pentaBDE is highly persistent in the environment, bioaccumulative and has a high potential for long-range environmental transport. These chemicals have been detected in humans in all regions. There is evidence of its potential for toxic effects in wildlife, including mammals.
Alternatives are available and used to replace these substances in many countries, although they might also have adverse effects on human health and the environment. Alternatives might not be available for use in military airplanes. The identification and also handling of equipment and wastes containing brominated diphenyl ethers is considered a challenge.
Polybromodiphenyl ether congeners including tetraBDE, pentaBDE, hexaBDE, and heptaBDE inhibit or suppress combustion in organic materials and therefore are used as additive flame retardants.
Listed under Annex B with acceptable purposes and specific exemptions (decision SC-4/17)
Risk profile (PDF)Risk management evaluation (RME) (PDF), addendum to the RME (PDF)
PFOS is a fully fluorinated anion, which is commonly used as a salt or incorporated into larger polymers. PFOS and its closely related compounds, which may contain PFOS impurities or substances that can result in PFOS, are members of the large family of perfluoroalkyl sulfonate substances.
perfluorooctane sulfonic acid (CAS No: 1763-23-1) and its salts perfluorooctane sulfonyl fluoride (CAS No: 307-35-7)
PFOS is both intentionally produced and an unintended degradation product of related anthropogenic chemicals. The current intentional use of PFOS is widespread and includes: electric and electronic parts, fire fighting foam, photo imaging, hydraulic fluids and textiles. PFOS is still produced in several countries.
PFOS is extremely persistent and has substantial bioaccumulating and biomagnifying properties, although it does not follow the classic pattern of other POPs by partitioning into fatty tissues but instead binds to proteins in the blood and the liver. It has a capacity to undergo long-range transport and also fulfills the toxicity criteria of the Stockholm Convention.
While alternatives to PFOS are available for some applications, this is not always the case in developing countries where existing alternatives may need to be phased in. For some applications like photo imaging, semi-conductor or aviation hydraulic fluids, technically feasible alternatives to PFOS are not available to date.
Acceptable purposes:
Photo-imaging, photo-resist and anti-reflective coatings for semi-conductor, etching agent for compound semi-conductor and ceramic filter, aviation hydraulic fluids, metal plating (hard metal plating) only in closed-loop systems, certain medical devices (such as ethylene tetrafluoroethylene copolymer (ETFE) layers and radio-opaque ETFE production, in‑vitro diagnostic medical devices, and CCD colour filters), fire‑fighting foam, insect baits for control of leaf-cutting ants from Atta spp. and Acromyrmex spp.
Specific exemptions:
Photo masks in the semiconductor and liquid crystal display (LCD) industries, metal plating (hard metal plating, decorative plating), electric and electronic parts for some colour printers and colour copy machines, insecticides for control of red imported fire ant, and termites, chemically driven oil production, carpets, leather and apparel, textiles and upholstery, paper and packaging, coatings and coating additives, rubber and plastics.