Subscribe to Email Updates

Follow us on LinkedIn

Blog

What are POPs?

Published by Colin Hutchins
Colin Hutchins
on Friday 21 April 2023


Last updated on Friday 5 May 2023

Throughout this post, many abbreviations and acronyms are used. To make it easier to read, we have left them in and included a glossary at the end!

What are POPs?

POPs (or persistent organic pollutants) are poisonous chemicals which have been and are still used in common household items, including fire-resistant furniture, waterproof clothing, non-stick kitchenware, grease-resistant food packaging and stain-resistant carpets.

persistent-organic-pollutants-large-crop1

The term persistent organic pollutants can be better understood as follows:

  • Persistent: not broken down by natural processes and therefore persist in the environment in water, soil, plants, animals etc.
  • Organic: carbon-based chemical compounds
  • Pollutants: contaminate the environment through their release into the atmosphere and watercourses

POPs are often referred to in the media as 'forever chemicals'.

Why Are POPs Harmful?

Materials containing POPs break down slowly over time, persist in soil and water supplies, and get into the food chain as a result, which then leads to a build-up of POPs in both animals and humans alike.

persistent-organic-pollutants-large-crop2

It is estimated that 99% of humans have POPs in their bodies and there is international concern that it is a cause of cancer and other diseases, potentially causing severe harm to humans, including deformities and birth defects in babies.

POPs have been released into the environment for several generations now and have spread through the ecosystem far beyond the point of pollution release. POPs build up in the body by a process known as bioaccumulation. For example, plants grow and absorb chemicals from the ground and air, herbivores eat the plants, and the chemicals (POPs) which can’t be broken down are retained in the animals' fat. Over time the POPs build up to higher and higher levels. This effect is then continued up the food chain, which means that predators higher up the food chain absorb higher concentrations of POPs which accumulate in their bodies. Many of these POPs chemicals are even found in mains drinking water.

What chemicals are known as POPs?

Many of the POPs chemicals are PFAS, PFAS are large, complex groups of manufactured chemicals that are ingredients in many everyday products, and used in manufacturing industries including automotive, aerospace, electronics and construction.

PFAS have been under scrutiny for many years. Research studies by scientists gave evidence of severe harm to genitive and reproductive health in workers in chemical plants dealing with PFAS. These studies were suppressed to protect the sale of these revolutionary new materials until finally this activity was exposed by legal challenges.

The well-known chemical PTFE was discovered by accident in 1938 and commercialised in 1945 under the name Teflon. PTFE was originally manufactured using PFOA, one of the PFAS. This chemical became known as C8, due to it having a chain of eight carbon atoms in its molecular structure. These carbon atoms are bonded to fluorine, which creates a very strong chemical bond, giving the final product its unique properties. 

PTFE is heat and ‘stick' resistant and protects against corrosion. Because of these qualities, products containing PTFE are found in many applications, including non-stick cookware, food packaging, stain-resistant carpets, non-crease clothes, waterproof clothing, plumbing tapes, fire-fighting foams, etc. With such a massive market, the quantities of PTFE material manufactured led to a commensurate quantity of waste and by-products of the PFAS used to make it, that needed to be disposed of. It is reported that some of this waste was buried in the ground and dumped into rivers for many years until public awareness was raised, which resulted in increasing legislation to control this pollution in recent years. 

Another well-known example of a POPs chemical is the pesticide DDT. DDT was used all over the world for many years, from 1940 onwards, to control the spread of insect-borne disease and as a pesticide in agriculture and households. DDT was banned in the USA in 1972 and in the UK in 1986. DDT is now banned worldwide by the Stockholm Convention, except for use in disease vector control purposes when no equally effective and efficient alternative is available. In September 2006, the World Health Organisation (WHO) declared its support for the indoor use of DDT in African countries where malaria remains a major health problem, citing that the benefits of the pesticide outweigh the health and environmental risks. The WHO position is consistent with the Stockholm Convention on POPs, which bans DDT for all uses except for malaria control. DDT does not readily remain in water; it tends to adhere to surfaces and particles. As a result of this, most DDT in humans is absorbed from food and is readily stored in body fat. There is no evidence of cancer in humans being caused by DDT. Whilst it is a POP, it is broken down by light, over a period of months or years.

What is being done about POPS?

The manufacture of Teflon and other similar products without the use of PFAS is being investigated, and the use of PFOA is subject to strict controls. Since 2002, manufacturers of PTFE have used a new process not requiring the use of PFOA. However, the alternative chemical HFPO-DA (known as Gen-X) have not been in use long enough to determine their long-term impact on health. Some countries and governments are attempting to ban the use of all PFAS.

POPs chemicals are found in drinking water all over the world. Water authorities have a duty to ensure water is wholesome, however, there are currently no statutory standards for PFASs in drinking water in England and Wales, nor is there a WHO guideline value. The DWI (Drinking Water Inspectorate) in the UK has taken a precautionary approach and produced tiered guideline values for water companies to adhere to. Other countries have also put restrictions on PFAS concentrations in drinking water and the European Union is in the process of adopting a standard of 0.1 micrograms per litre (ug/L) for 20 individual substances. The DWI considers that this approach remains valid and that the guidance limit of 0.1 ug/L for PFAS is a robust level with an appropriate margin of safety to ensure the wholesomeness of drinking water. (0.1 ug/L = 0.1 parts per billion, ppb)

The United States EPA has issued Health Advisory levels for the following PFAS:

  • PFOA: 0.004 parts per trillion (ppt)
  • PFOS: 0.02 ppt
  • Gen-X chemicals (replacement for PFOA): 10 ppt
  • PFBS (Replacement for PFOS): 2,000 ppt

Since the levels for PFOA and PFOS are not measurable using current scientific methods, the EPA recommends taking steps if any presence of these chemicals is detected. Further, they must be reported to the EPA if detected at levels of 4 ppt or more – 1000 times the ‘safe’ limit for PFOA!

The WHO has set a recommended limit for DDT of 1 ug/L (or 1 ppb) for drinking water; this level is to protect human health and may not be sufficient to protect the environment. (Aquatic life is much more susceptible to DDT than humans).

What do these numbers mean? Millions, billions and trillions are BIG numbers!

An Olympic-sized swimming pool holds 2.5 million litres, or 50 billion drops. 1 part per trillion is like 1 drop of ink in 20 Olympic swimming pools, mixed thoroughly!

1 trillion hairs placed side by side would reach around the equator, fine fair hair, 0.04 mm thick. 1 single hair breadth on the equator is 1 part per trillion.

Put another way, it is the equivalent of 1 second in 32,000 years.

Yes, it's hard to take in! And the 'safe' level of PFOA is 4 parts per THOUSAND TRILLION!

An Overview of POPs Legislation

The 1979 Convention on Long-Range Transboundary Air Pollution initially focused on Sulphur Dioxide pollution, but the scope of the convention has since been extended to include the 1991 VOC protocol, the 1998 Aarhus Protocol on Persistent Organic Pollutants and others.

On 22nd May 2001, the United Nations adopted the Stockholm Convention on Persistent Organic Pollutants, and this treaty came into force on 17th May 2004. 152 nations are signatories, and many have ratified the treaty.

The list of POPs Chemicals stated in the Stockholm Convention are split into 3 categories:

  • Pesticides
  • Industrial Chemicals
  • Unintentional Production

They are also graded as:

  • Those where production should be eliminated
  • Those where production should be restricted
  • Those where their unintentional release should be reduced

Initially there were 12 chemicals listed, but this list now numbers 35 with further recommendations for inclusion. 19 are manufactured pesticides and 13 are manufactured industrial chemicals, in addition to by-products.

The UK government, as a signatory to the Stockholm Convention, introduced The Persistent Organic Pollutants Regulations 2007 to control the use of POPs, and control the handling of waste products containing POPs. Following many amendments, this regulation was re-cast for clarity in 2019 as Regulation (EU) 2019/1021.

See Article 3 and Article 7.

On 4th October 2019, at the 15th meeting of the Persistent Organics Pollutants Review Committee (POPRC), international scientists recommended that a group of hazardous chemicals - Perfluoro hexane sulphonic acid (PFHxS), its salts, and PFHxS-related compounds - be eliminated to better protect human health and the environment from its harmful impacts. Even though these chemicals have only 6 carbon atoms, they are still grouped as PFAS. PFAS had been used in manufacture for more than 75 years by this date…

Current guidance from the Environment Agency mentions waste upholstered domestic seating, which is considered to contain POPs unless it can be demonstrated otherwise, e.g. seating recently manufactured in accordance with the regulations. Any waste containing POPs must not be re-used or recycled, and must be destroyed, typically by incineration in an Energy-from-Waste plant.

The guidance sets out that the waste must be controlled at all stages of waste transfer: collection, segregation, storage, transport, shredding or other processing, and finally incineration. The guidance is clear on the need to store and process the waste in a covered, contained area with an impervious floor, and any dust arising from processing must be controlled and contained.

Dust Control is often achieved through the use of correctly-positioned misting equipment. This creates a finely-atomised mist of dust suppressant liquid (water which can be combined with specialist surfactants) which captures and contains the dust, preventing its spread. Expert advice should be sought to ensure that abatement measures are specified correctly for the specific circumstances.

Due to the significant long-term environmental damage and health risks, it is essential that all stakeholders support this guidance.

Even today in the UK, PFAS are not yet banned from food packaging. As recently as 2022, The European Chemicals Agency (ECHA) proposed to ban the use of PFAS in firefighting foams in Europe. The proposal was made available on the ECHA website on 23 February 2022. This is being consulted on by ECHA’s Committee for Risk Assessment and Committee for Socio-Economic Analysis, and a decision will be reached based on this assessment during 2023.

The control and restriction of the release of PFAS and other POPs is ongoing, and much more work needs to be done. 

How Do POPs Affect Me?

As we have seen, this problem is caused by using these products in many areas of daily life, from flame-retardant furniture to waterproof clothing. Most of us encounter these products several times each day where they may be relatively harmless until they start to become damaged or fragmented, releasing dust particles which can begin to migrate into the environment. This problem affects all of us, and is influenced by all of us, whether we are purchasing products, disposing of our personal household waste products, or managing and processing waste. It is important to follow government and local authority guidance as it evolves, to help remove these chemicals from the environment.

How Can POPs be Controlled?

While PFAS are widespread in the environment, it is possible to remove them from water using reverse osmosis and other filtration methods. While the manufacture, sale and use of items containing POPs is now banned, there are still many items in circulation that contain POPs. At some point, these items will be disposed of via the waste management system.

As a first step, the government have released guidance on storing and disposing of waste containing POPs, which includes guidance on shredding upholstered seating containing POPs and minimising fugitive dust emissions.  The guidance states that you must minimise the release of particulates when shredding by reducing emissions from the shredder, the area around the shredder and the shredder building.

persistant-organic-pollutants-sofa-landfill-photo-medium

Examples of methods for minimising fugitive emissions include using dust suppression systems to mist over shredder hoppers, conveyor systems and within buildings, and using dust suppression cannons to control point source emissions of particulates.

What can Corgin do to help?

Further research is needed to understand how the POPs are spread by dust, what size of dust particles pose the greatest problem, and how best to capture these. It seems logical that the finest dust is hardest to capture, and most likely to remain airborne for the longest time, thus travelling the furthest. During a shredding operation, for example, a 10mm fragment of wood is unlikely to travel more than a few metres, whereas a sub-micron particle will take many hours to settle or could remain airborne indefinitely.

Click here to find out more about how Corgin can help control POPs and what  products we offer for this application.

Glossary of Acronyms

  • C8 - A range of extremely stable chemicals with 8 carbon atoms in their molecule chain (aka. PFOA)
  • DDT - Dichloro-diphenyl-trichloroethane (C14H9Cl5) (an insecticide used for disease control)
  • DWI - UK Drinking Water Inspectorate
  • ECHA  - European Chemicals Agency
  • EPA  - United States Environmental Protection Agency
  • GEN-X  - HFPO-DA or HEXAFLUOROPROPYLENE OXIDE DIMER ACID (C6HF11O3) (replacement for PFOA)
  • PFAS - PERFLUOROALKYL and POLYFLUOROALKYL SUBSTANCES
  • PFBS - PERFLUOROBUTANESULPHONIC ACID (C4HF9O3S) (replacement for PFOS)
  • PFHxS - PERFLUORO HEXANE SULPHONIC ACID (C6HF13O3S) (one of the PFAS group)
  • PFOA - PERFLUOROOCTANOIC ACID (C8HF15O2) (a surfactant used to manufacture other chemicals)
  • PFOS - PERFLUOROOCTANE SULPHONATE (C8HF17O3S) (a surfactant used to manufacture other chemicals)
  • POPS - Persistent Organic Pollutants
  • PTFE - POLYTETRAFLUOROETHYLENE (C2F4)n  (a synthetic fluoropolymer of tetrafluoroethylene that has numerous applications. It is one of the best-known and widely applied PFASs. the commonly known brand name of PTFE-based composition is Teflon by Chemours, a spin-off from Dupont, who originally discovered the compound in 1938)
  • WHO - United Nations World Health Organisation