UPOPs (Unintentional POPs)

What are UPOPs?

Unintentional Persistent Organic Pollutants (UPOPs) are POPs, toxic, man-made, hazardous chemicals that have dangerous effects on the environment and our health. UPOPs are not voluntarily produced or released into the environment but they derive from anthropogenic sources: they are emitted during incomplete combustion process involving organic matter and chlorine or are created as by-products of manufacturing other chemicals.

Seven UPOPs are listed in Annex C of the Stockholm Convention on POPs, a global treaty to protect human health and the environment from persistent organic pollutants entered into force in 2004, as follows:

Hexachlorobutadiene (HCBD) - listed since 2015 in Annexes A and since 2017 in Annex C - HCBD was used as a solvent for other chlorine-containing compounds.

Polychlorinated naphtalenes (PCN) - listed since 2015 in Annexes A and C - PCNs were used as insulating coatings for electrical wires, as wood preservatives, as rubber or plastic additives, for capacitor dielectrics and in lubricants.

Pentachlorobenzene (PeCB) - listed since 2009 in Annexes A and C - PeCBz was used in PCBs products, in dyestuff carriers, as a fungicide, a flame retardant and as a chemical intermediate, e.g. for the production of quintozene.

Polychlorinated biphenyls (PCBs) - listed since 2004 in Annexes A and C - PCBs have been used among other as coolants and lubricants in transformers, capacitors and other electrical equipment because they do not burn easily and are good insulators.

Hexachlorobenzene (HCB) - listed since 2004 in Annexes A and C - HCB has been widely used as a pesticide to protect the seeds of onions and sorghum, wheat and other grains against fungus. It has also been used to make fireworks, ammunition and synthetic rubber.

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDF) - listed since 2004 in Annexes C - PCDD and PCDF have never been used as commercial products nor were they intentionally manufactured for any reason other than laboratory purposes. They are released during incomplete combustion of municipal waste or medical waste in open burning settings.

Except for dioxin (PCDD) and furans (PCDF), all the unintentional POPs listed in Annex C have also had intentional production in the past and are equally listed in Annex A.

Article 5 of the Stockholm Convention states that Parties must take measures to reduce, and where feasible, eliminate releases of unintentionally produced POPs.

BAT/BEP Guidelines

UNEP developed the BAT/BEP Guidelines relevant to Article 5 and Annex C to assist Parties with their obligations under the Stockholm Convention to promote and require the use of Best Available Techniques (BAT) and the application of Best Environmental Practices (BEP) regarding UPOPs. The guidelines were last updated in 2021.

Toolkit for Identification and Quantification of Releases of Dioxins, Furans and Other Unintentional POPs

Each Party must also develop an action plan where releases of Unintentional POPs are identified, characterized and addressed.

UNEP developed the Toolkit to assist parties in establishing release inventories of UPOPs that are consistent in format and content, ensuring that it is possible to compare results, identify priorities, mark progress, and follow changes over time at the country level, as well as regional and global levels.

The Toolkit consists of a manual and an EXCEL database. It is designed as a simple and standardized methodology containing default emission factors for the sources of UPOPs. It also contains explanations and example inventories.

The toolkit exist also as an Electronic Toolkit.

One unintentional chemical has been proposed for listing under the Stockholm Convention: Long-chain perfluorocarboxylic acids (PFCAs). See the Interactive timeline of POPs listed under the Stockholm Convention

GMP Dashboard

The UNEP/GEF Global Monitoring project measures concentrations of POPs, many of which are UPOPs, in air, human milk and samples of national interest. See the results in the interactive dashboard.