Temporal changes in halogenated flame-retardant concentrations in foodstuffs and indoor and outdoor environments: implications for human exposure

Ma, Yulong ORCID: 0000-0002-6302-3168 (2024). Temporal changes in halogenated flame-retardant concentrations in foodstuffs and indoor and outdoor environments: implications for human exposure. University of Birmingham. Ph.D.

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Abstract

Brominated flame retardants (BFRs) have been found to exert significant adverse impacts on environmental safety and human health. With global restrictions in use of legacy BFRs, demand for novel BFRs (NBFRs) is expected to rise. However, little is known about how global restrictions could impact on human exposure to legacy and emerging BFRs. Therefore, animal-derived food items were collected from Nigeria (n = 26), the US (n = 72), and the UK (n = 108) for BFR analysis. Comparison with previous dietary studies reveals high concentrations of polybrominated diphenyl ethers (PBDEs) in Nigerian foodstuffs in recent years with associated high dietary exposure, while PBDE concentrations in US foodstuffs seemed to be relatively constant with time. Concentrations of NBFRs, but not PBDEs, in US food items were significantly impacted by price, raising the issue of environmental justice. In UK foodstuffs, however, concentrations of PBDEs and hexabromocyclododecane (HBCDD) declined significantly between 2015 and 2020-21, while concentrations of NBFRs increased considerably. Reassuringly, comparison of our exposure estimates with health-based limit values suggests minimal adverse health effects of dietary intake of BFRs on residents of the three countries.

Impact of legislation on BFR concentrations in UK indoor and outdoor environments is also explored. Paired floor dust samples (n = 30) and indoor air samples (n = 30) from 8 UK homes, together with outdoor air samples (n = 16), were collected in Birmingham, UK between 2021 – 2022. These samples enable us to estimate human exposure to BFRs via dust ingestion and inhalation in the UK. BDE-209 and decabromodiphenyl ethane (DBDPE) were the main BFRs in UK indoor and outdoor environments. The maximum concentration of DBDPE (10,000 pg/m3) in outdoor air is the highest reported anywhere to date, with DBDPE concentrations in UK indoor dust and indoor air also among the highest globally, likely due to its frequent use in construction materials and home appliances. For outdoor air, we observed significant correlations between concentrations of tri- to hepta-BDEs and HBCDD and temperature. These suggest primary emissions from active use of these BFRs have diminished and are now outweighed by secondary emissions (e.g., evaporation of BFRs from soil). Conversely, the lack of significant correlations between temperature and concentrations of BDE-209 and DBDPE, indicate ongoing primary emissions from indoor sources remain important for these BFRs. Comparison with earlier studies in Birmingham reveals significant declines in concentrations of legacy BFRs in UK indoor and outdoor environments over the last decade, but significant increases for concentrations of NBFRs. While there appears minimal health burdens from BFR exposure for UK adults, dust ingestion of BDE-209 may pose significant risk for UK toddlers.

We also analysed dust samples from inside (n = 6) and outside (n = 30) of five UK electrical and electronic waste (e-waste) recycling facilities for BFR concentrations. One of the studied e-waste recycling facilities was identified as a likely source of BFR contamination to UK urban environments. Further, industrial activities were also identified as another potential source of NBFRs (but not PBDEs or HBCDD). This likely reflects the phase-out of PBDEs and HBCDD and the use of NBFRs as substitutes in industrial activities in the UK. To the best of our knowledge, this is the first study evaluating impacts of regulated e-waste recycling activities on environmental contamination with BFRs in Europe.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

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