POPs - Persistent Organic Pollutants

What are POPs?

A growing body of scientific evidence indicates that exposure to very low doses of certain POPs – which are among the most toxic substances ever created – can lead to cancer, damage to the central and peripheral nervous systems, diseases of the immune system, reproductive disorders, and interference with normal infant and child development.

Another concern is the growing accumulation of unwanted and obsolete stockpiles of pesticides and toxic chemicals, particularly in developing countries. Dump sites and toxic drums from the 1950s, ‘60s, and ‘70s are now decaying and leaching chemicals into the soil and poisoning water resources, wildlife, and people. A great deal of infrastructure and equipment such as electrical transformers and capacitors are also at or near the end of their useful lives and may leak dangerous chemicals such as PCBs.

General characteristics:

  • Man-made – POPs are either used as pesticides, consumed by industry, or generated unintentionally as by-products of various industrial processes.
  • Toxic – Of all the pollutants released into the environment every year by human activity, persistent organic pollutants, or POPs, are among the most dangerous. They are highly toxic, causing an array of adverse effects, notably death, disease, and birth defects among humans and animals.
  • Persistent – These highly stable compounds can last for years or decades before breaking down.
  • Mobile – They circulate globally through a process known as the “grasshopper effect”. POPs released in one part of the world can, through a repeated (and often seasonal) process of evaporation, deposit, evaporation, deposit, be transported through the atmosphere to regions far away from the original source.
  • Bioaccumulative – 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.

Persistent Organic Pollutants (POPs)

Initially, twelve POPs have been recognized as causing adverse effects on humans and the ecosystem and these can be placed in 3 categories:


Pesticides: aldrin, chlordane, DDT, dieldrin, endrin, heptachlor, hexachlorobenzene, mirex, toxaphene;
Industrial chemicals: hexachlorobenzene, polychlorinated biphenyls (PCBs); and
By-products: hexachlorobenzene; polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/PCDF), and PCBs.

Dirty Dozen– The initial 12 POPs recognized as requiring the most urgent action are:

  1. Aldrin
  2. Chlordane
  3. DDT
  4. Dieldrin
  5. Endrin
  6. Heptachlor
  7. Hexachlorobenzene (HCB)
  8. Mirex
  9. Toxaphene
  10. PCB
  11. Dioxins
  12. Furans

And the New POPs are the following:

  1. Alpha hexachlorocyclohexane
  2. Beta hexachlorocyclohexane
  3. Decabromodiphenyl ether (commercial mixture, c-decaBDE)
  4. Dicofol
  5. Hexabromobiphenyl
  6. Hexabromocyclododecane
  7. Hexabromodiphenyl ether and heptabromodiphenyl ether (commercial octabromodiphenyl ether)
  8. Hexachlorobutadiene
  9. Lindane
  10. Pentachlorobenzene
  11. Pentachlorophenol and its salts and esters
  12. Perfluorooctane sulfonic acid (PFOS), its salts and perfluorooctane sulfonyl fluoride (PFOSF)
  13. Perfluorooctanoic acid (PFOA), its salts and PFOA-related compounds
  14. Polychlorinated naphthalenes
  15. Short-chain chlorinated paraffins (SCCPs)
  16. Technical endosulfan and its related isomers
  17. Tetrabromodiphenyl ether and pentabromodiphenyl ether (commercial pentabromodiphenyl ether)

Under Stockholm Convention the POPs Chemicals are classified in three Annexes depending on the action that has to be taken for the particular POPs chemical.

Annex A – where Parties must take measures to eliminate the production and use of the chemicals listed under Annex A, such as:

  1. Aldrin   
  2. Chlordane          
  3. Chlordecone
  4. Decabromodiphenyl ether (commercial mixture, c-decaBDE)
  5. Dicofol
  6. Dieldrin
  7. Endrin  
  8. Heptachlor        
  9. Hexabromobiphenyl      
  10. Hexabromocyclododecane (HBCDD)       
  11. Hexabromodiphenyl ether and heptabromodiphenyl ether
  12. Hexachlorobenzene (HCB)          
  13. Hexachlorobutadiene
  14. Alpha hexachlorocyclohexane
  15. Beta hexachlorocyclohexane
  16. Lindane
  17. Mirex
  18. Pentachlorobenzene
  19. Pentachlorophenol and its salts and esters
  20. Polychlorinated biphenyls (PCB)
  21. Polychlorinated naphthalenes
  22. Perfluorooctanoic acid (PFOA), its salts and PFOA-related compounds
  23. Short-chain chlorinated paraffins (SCCPs)
  24. Technical endosulfan and its related isomers
  25. Tetrabromodiphenyl ether and pentabromodiphenyl ether
  26. Toxaphene

Annex B – 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, such as:

DDT

Perfluorooctane sulfonic acid, its salts and perfluorooctane sulfonyl fluoride

Annex C – 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, such as:

Pentachlorobenzene

Polychlorinated biphenyls (PCB)

Polychlorinated dibenzo-p-dioxins (PCDD)

Polychlorinated dibenzofurans (PCDF)

Polychlorinated naphthalenes

Chemicals proposed for listing under the Convention

Currently, the following chemicals are under review:

Dechlorane Plus
Methoxychlor
UV-328
Chlorpyrifos
Chlorinated paraffins with carbon chain lengths in the range C14-17 and chlorination levels at or exceeding 45 per cent chlorine by weight
Long-chain perfluorocarboxylic acids, their salts and related compounds