Brominated flame retardants

Content

Introduction

Flame retardants are chemical compounds that are added to household and industrial products to prevent them from catching fire or to slow the spread of flames.

They are mainly used in:

  • furniture, upholstery, mattresses, carpets, curtains
  • electronic and electrical devices, such as desktop and laptop computers, telephones, smartphones, televisions, household appliances
  • building materials, including electrical substations and networks, insulation materials based on polystyrene and polyurethane foams
  • seats and seat covers, bumpers and other compartments of automobiles, airplanes and trains

There are three main categories of flame retardants, i halogenated compounds which include i chlorinated (PCB) and brominated compounds, the organophosphorus compounds and inorganic compounds

Brominated flame retardants (Brominated Flame Retardants - BFR) comprise five different chemical categories:

  • Polybrominated diphenyl ethers (PBDE, from the English polybrominated diphenyl ethers), present in plastics, fabrics, electrical components and circuits
  • polybrominated biphenyls (PBB, from the English polybrominated biphenyls), present in household appliances, fabrics and plastic foams
  • hexabromocyclododecanes (HBCDDs, from the English hexabromocyclododecanes), used in "thermal insulation in buildings
  • tetrabromobisphenol A (TBBPA from English tetrabromobisphenol A) and other phenols, present in electrical circuits and thermoplastics (especially in televisions)
  • other brominated flame retardants

Each of the first two chemical classes (PBDE and PBB) is made up of 209 different compounds, called congeners, which differ in the number and position of the bromine atoms.

Used in considerable quantities since the 1970s, many of them are no longer produced and have been eliminated from the market; others are still in use, albeit in an increasingly regulated manner.

Due to their chemical structure, brominated flame retardants are very stable and remain in the environment for years. Since they have the ability to dissolve in fats and are not easily degraded (metabolized), they tend to accumulate in the fat part of organisms, giving the phenomenon of bioaccumulation. The content of contaminants is transferred along the food chain (plants-herbivores-carnivores) so that the concentration of contaminants in organisms increases passing from a lower to a higher level of the trophic chain, giving rise to the phenomenon This phenomenon implies that an organism occupying a higher level in the food chain may have higher internal levels of contaminants.

The European Food Safety Authority (EFSA) has drawn up several scientific opinions on the presence of these substances in food and has established which are more worrying because they are present to a greater extent in the diet. For example, among ethers polybrominated diphenyls (PBDEs), 8 congeners most relevant for dietary exposure have been identified: BDE-28, -47, -99, -100, -153, -154, -183, -209.

BFRs pose a risk to human health due to the many side effects they can cause.

Sources of exposure

The routes of exposure to brominated flame retardants (BFRs) are varied and include diet and house dust.

BFRs have a high chemical stability and therefore remain in the environment for many years, dispersing in water, soil and air until they enter the food chain. The European Food Safety Authority (EFSA) has assessed that foods of animal origin such as fish, meat, milk and derived products, given their fat content, can be considered the major vehicles of these contaminants in man. Based on the data available to date for various congeners belonging to different chemical categories, EFSA concluded that dietary exposure does not represent a health problem. However, it promotes their monitoring in food and the increase in data production. on health effects, reserving the right to update their opinion if new scientific evidence is produced. In the meantime, the indication for the population is to vary the diet as much as possible and limit the consumption of foods that are very high in fat (for example, fish such as salmon or tuna) for the most vulnerable groups of the population, such as children and pregnant women.

Not being chemically bound to the materials that contain them, brominated flame retardants (BFRs) are released from the surfaces of the products that contain them in the home, car and office, depositing in household dust. Through the dust they can be inhaled, deposited on the skin or swallowed. Children, having greater contact with the ground and the habit of often putting their hands to their mouths, are at greater risk of exposure to these substances in the home environment.

Effects on health

Numerous studies conducted on animal models, on cell cultures and on the population, have shown that exposure to brominated flame retardants, to polybrominated diphenyl ethers (PBDE) in particular, causes an "alteration of the balance of thyroid hormones, has harmful effects on the liver and reproductive system and alters the correct neurological development of the fetus with consequences on attention, memory and learning (cognitive) capacity.

The flame retardants are counted among the Endocrine Disruptors, therefore they have the ability to alter the correct reproductive development, male and female, of the fetus but also to compromise the reproductive functions in adults, especially in men, due to their greater interaction with the receptor for androgens, prevalent in man, or for effects on the synthesis of sex hormones.

These substances are able to overcome the barrier represented by the placenta reaching the fetus and can be transferred from mother to child even during breastfeeding. Particular attention, therefore, considering the potential undesirable effects that can also affect adult life, must be placed in the reduce exposure during these stages of development.

Regulation

The "increase in scientific evidence of the effects of brominated flame retardants (BFRs) on health has led to the involvement of European and American decision makers in the request for data, information, study promotions and in the" adoption of legislative measures to reduce or discontinue " use and sale of some flame retardants.

In particular:

  • ban on the sale of two commercial blends of polybrominated diphenyl ethers (PBDEs), PentaBDE and OctaBDE, in concentrations greater than 0.1%, as of August 2004 (European Directive 2003/11 / EC)
  • ban by the US of the industrial production of Penta and OctaBDE blends since the end of 2004, and in use since 2006
  • ban on the use of polybrominated biphenyls (PBBs) and PBDEs in all electrical and electronic components since July 2006 (European Directive 2002/95 / EC)
  • a ban on the PBDE blend, DecaBDE in June 2008 (European Court of Justice, Case C-14/06). Following some European states, such as Sweden and Norway, have banned the use of these blends also in the manufacture of fabrics, furniture, insulation materials and cables.
  • inclusion of the PentaBDE and OctaBDE mixtures in the list of persistent substances whose use and production should be eliminated to be eliminated (Stockholm Convention on Persistent Organic Pollutants, May 2009)
  • six scientific opinions on the main groups of BFRs and the potential risks to public health arising from their presence in the food produced of the European Food Safety Authority (EFSA), between 2010 and 2012 request from the European Commission
  • production and use of DecaBDE blends, it continues to be allowed in the United States, although some individual states have introduced restrictions. Recently, in July 2019, the US Environmental Protection Agency (EPA) proposed a regulation to ban the use of such mixtures, except in aircraft and aerospace vehicles, starting from December 2020

Bibliography

Directive 2003/11 / EC of the European Parliament and of the Council of 6 February 2003 amending the twenty-fourth amendment of Council Directive 76/769 / EEC relating to restrictions on the placing on the market and use of certain dangerous substances and preparations (pentabromodiphenyl ether, octabromodiphenyl ether)

Directive 2002/95 / EC of the European Parliament and of the Council of 27 January 2003 on the restriction of the use of certain hazardous substances in electrical and electronic equipment

Judgment of the Court (Grand Chamber) 1 April 2008 - European Parliament (case C-14/06)

Environmental Protection Agency (EPA). Regulation of Persistent, Bioaccumulative, and Toxic Chemicals Under TSCA Section 6 (h), US Federal Register, Proposed Rules, vol. 84 n ° 145, 2019

Environmental Protection Agency (EPA). Decabromodiphenyl Ether (DecaBDE); Regulation of Persistent, Bioaccumulative, and Toxic Chemicals Under TSCA Section 6 (h), 2021

European Food Safety Authority (EFSA). Scientific Opinion on Polybrominated Biphenyls (PBBs) in Food. EFSA Journal. 2010; 8: 1789

European Food Safety Authority (EFSA). Scientific Opinion on Polybrominated Diphenyl Ethers (PBDEs) in Food. EFSA Journal. 2011; 9: 2156

European Food Safety Authority (EFSA). Scientific Opinion on Tetrabromobisphenol A (TBBPA) and its derivatives in food. EFSA Journal. 2011; 9: 2477

European Food Safety Authority (EFSA). Scientific Opinion on Brominated Flame Retardants (BFRs) in Food: Brominated Phenols and their Derivatives. EFSA Journal. 2012; 10: 2634

European Food Safety Authority (EFSA). Scientific Opinion on Emerging and Novel Brominated Flame Retardants (BFRs) in Food. EFSA Journal. 2012; 10: 2908

Further links

European Food Safety Authority (EFSA). Brominated flame retardants

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