Editing Polybrominated diphenyl ethers (section)

==Health and environmental concerns==

===Exposure===

Polybrominated diphenyl ethers (PBDEs) can be released into the environment where they are used or produced, possibly entering air, water, soil or the [[human digestive system]] when consumed, inhaled or via the skin.<ref name="cdc">{{cite web |title=Public Health Statement for PBDEs |url=https://wwwn.cdc.gov/TSP/PHS/PHS.aspx?phsid=1449&toxid=183 |publisher=Agency for Toxic Substances and Disease Registry, US Centers for Disease Control and Prevention |access-date=24 December 2024 |date=8 May 2017}}</ref><ref name="hc">{{cite web |title=Polybrominated diphenyl ethers (PBDEs) – information sheet |url=https://www.canada.ca/en/health-canada/services/chemical-substances/fact-sheets/chemicals-glance/polybrominated-diphenyl-ethers-public-summary.html |publisher=Health Canada, Government of Canada |access-date=24 December 2024 |date=14 September 2023}}</ref> Despite the banning and phase out of several forms of PBDEs, many consumer products still contain them in the 21st century, and represent potential exposure sources, including furniture and other consumer products containing [[polyurethane foam]], appliances, pipes, plastics, and old electronic equipment.<ref name=cdc/><ref name="efsa-over">{{cite web |title=Brominated flame retardants |url=https://www.efsa.europa.eu/en/topics/topic/brominated-flame-retardants |publisher=European Food Safety Authority |access-date=24 December 2024 |date=23 October 2024}}</ref>

Generally, governments have determined that PBDEs are not harmful to human health in the exposure amounts assessed.<ref name=cdc/><ref name=hc/><ref name=efsa24/> Ingestion of house [[dust]] accounts for 80–90% of total PBDE exposure, while the remaining exposure occurs from food ingestion.<ref name=cdc/><ref name=hc/> PBDE-contaminated foods, particularly those high in fat content, such as fatty meats or fish, are possible sources of exposure.<ref name=cdc/> In [[breastfeeding]] infants, breast milk may be an exposure source because PBDEs can be present in the mother and her milk.<ref name=cdc/> Various other food items may contain PBDEs, including meat, meat products, dairy products,  and seafood.<ref name=cdc/><ref name="efsa24">{{cite journal |author=EFSA Panel on Contaminants in the Food Chain |title=Update of the risk assessment of polybrominated diphenyl ethers (PBDEs) in food |journal=EFSA Journal |date=24 January 2024 |volume=22 |issue=1 |page=e8497 |doi=10.2903/j.efsa.2024.8497 |pmid=38269035 |pmc=10807361}}</ref> 

PBDEs have not been detected beyond trace levels in water.<ref name=cdc/> In the environment, soils and sediments are the major deposits for PBDEs.<ref name=cdc/> PBDEs can enter soil from discarded products, such as in landfills. As [[biosolids]] (sewage) may contain PBDEs, exposure from soils or farmlands that have been fertilized with biosolids may occur.<ref name=cdc/> [[Wildlife]] may have exposure by consuming foods containing PBDEs, whereas organisms that live in sediments may be contaminated by PBDEs.<ref name=hc/>

===Excretion===
PBDEs and their [[metabolite]]s are [[Excretion|excreted]] mainly in the feces and some in the urine.<ref name=cdc/> Owing to their deposition in body fat stores, some PBDEs remain in the body for many years, and may enter the bodies of unborn babies via the [[placenta]].<ref name=cdc/>

===Research on health effects===
Nothing certain has been established about the effects of PBDEs on human health.<ref name=cdc/><ref name=hc/><ref name=efsa24/> Most information regarding toxicity of PBDEs and their metabolites is from early-stage animal studies.<ref name=efsa24/> Evidence for PBDE-mediated effects from human studies in systems other than the developing nervous system, such as in cancer development, is inconclusive or non-existent.<ref name=cdc/> Particularly for the potential effects of PBDEs on the developing fetus, research has focused on the health status of mothers and [[gestational age]] of the infant.<ref name="wang">{{cite journal |vauthors=Wang Z, Zhang C, Williams PL, Bellavia A, Wylie BJ, Hacker MR, Kannan K, Bloom MS, Hunt KJ, Hauser R, James-Todd T|display-authors=3 |title=Polybrominated diphenyl ethers in early pregnancy and preterm birth: Findings from the NICHD Fetal Growth Studies |journal=International Journal of Hygiene and Environmental Health |volume=243 |issue= |pages=113978 |date=June 2022 |pmid=35569252 |pmc=9302707 |doi=10.1016/j.ijheh.2022.113978|bibcode=2022IJHEH.24313978W }}</ref>

===Sediment contamination===
Increasing environmental concentrations and changing distributions of PBDEs in sediments of the [[River Clyde|Clyde]] River Estuary in Scotland, UK have been assessed.<ref name="VaneMa2009">{{cite journal|last1=Vane|first1=Christopher H.|last2=Ma|first2=Yun-Juan|last3=Chen|first3=She-Jun|last4=Mai|first4=Bi-Xian| title=Increasing polybrominated diphenyl ether (PBDE) contamination in sediment cores from the inner Clyde Estuary, UK | journal=Environmental Geochemistry and Health | volume=32|issue=1|year=2009|pages=13–21|issn=0269-4042|doi=10.1007/s10653-009-9261-6|pmid=19347590|s2cid=102768|url=http://nora.nerc.ac.uk/id/eprint/9129/1/Vane_etal_2010_EGH.pdf}}</ref> Analysis of six sediment cores each of 1 m depth from [[Glasgow]] city to Greenock revealed that total concentrations increased toward the river bed surface (0–10&nbsp;cm). Amounts of PBDE ranged from 1 to 2,645&nbsp;µg/kg (dry wt. sediment) with a mean of 287&nbsp;µg/kg (dry wt. sediment).<ref name="VaneMa2009"/> Down-core PBDE congener profiles showed that higher concentrations were due to elevated levels of BDE-209. The majority of the sediment records clearly showed a change from mainly lower molecular weight BDEs 47,99, 183, 153 at lower depths to BDE-209 near the surface, a change in congener and homologue group patterns that corresponds to the restrictions of penta- and octaBDE commercial mixtures under EU law in 2004–2006.

While biodegradation is not considered the main pathway for PBDEs, [[Photodissociation|photolysis]] and [[pyrolysis]] can be of interest in studies of transformation of PBDEs.<ref>{{cite journal |author=Hutzinger O |title=Polybrominated dibenzodioxins and dibenzofurans |journal=[[Chemosphere (journal)|Chemosphere]] |volume=16 |pages= 1877–1880 |year=1987 |doi=10.1016/0045-6535(87)90181-0 |last2=Thoma |first2=H. |issue=8–9 |display-authors=etal|bibcode=1987Chmsp..16.1877H }}</ref><ref>{{cite journal |author=Watanabe I |title=Polybrominated diphenyl ethers in marine fish, shellfish and river sediments in Japan |journal=[[Chemosphere (journal)|Chemosphere]] |volume=16 |pages= 2389–2396 |year=1987 |doi=10.1016/0045-6535(87)90297-9 |last2=Kashimoto |first2=Takashi |last3=Tatsukawa |first3=Ryo |issue=10–12 |display-authors=etal|bibcode=1987Chmsp..16.2389W }}</ref>