Spatiotemporal Trends of Legacy and Alternative Flame Retardants in Harbor Seals from the Coasts of California, the Gulf of Maine, and Sweden

Exposure of Peregrine Falcons to Halogenated Flame Retardants: A 30 Year Retrospective Biomonitoring Study across North America

Compared to aquatic ecosystem, terrestrial systems have been subjected to fewer investigations on the exposure to halogenated flame retardants (HFRs). Our study utilized peregrine falcon eggs collected from multiple habitats across North America to retrospectively explore both spatial distribution and temporal changes in legacy (e.g., polybrominated diphenyl ethers) and alternative HFRs over a 30 year period (1984-2016). The results reveal intensive HFR exposure in terrestrial ecosystems and chemical-specific spatiotemporal distribution patterns. The correlations between egg levels of the selected HFRs and human population density clearly illustrated a significant urban influence on the exposure of this wildlife species to these HFRs and subsequent maternal transfer to their eggs. Temporal analyses suggest that, unlike aquatic systems, terrestrial ecosystems may undergo continual exposure to consistently high levels of legacy HFRs for a long period of time. Our findings collectively highlight the effectiveness of using peregrine eggs to monitor terrestrial exposure to HFRs and other bioaccumulative chemicals and the need for continuous monitoring of HFRs in terrestrial ecosystems.

Alternative and legacy flame retardants in marine mammals from three northern ocean regions

Flame retardants are globally distributed contaminants that have been linked to negative health effects in humans and wildlife. As top predators, marine mammals bioaccumulate flame retardants and other contaminants in their tissues which is one of many human-imposed factors threatening population health. While some flame retardants, such as the polybrominated diphenyl ethers (PBDE), have been banned because of known toxicity and environmental persistence, limited data exist on the presence and distribution of current-use alternative flame retardants in marine mammals from many industrialized and remote regions of the world. Therefore, this study measured 44 legacy and alternative flame retardants in nine marine mammal species from three ocean regions: the Northwest Atlantic, the Arctic, and the Baltic allowing for regional, species, age, body condition, temporal, and tissue comparisons to help understand global patterns. PBDE concentrations were 100-1000 times higher than the alternative brominated flame retardants (altBFRs) and Dechloranes. 2,2',4,5,5'-pentabromobiphenyl (BB-101) and hexabromobenzene (HBBZ) were the predominant altBFRs, while Dechlorane-602 was the predominant Dechlorane. This manuscript also reports only the second detection of hexachlorocyclopentadienyl-dibromocyclooctane (HCDBCO) in marine mammals. The NW Atlantic had the highest PBDE concentrations followed by the Baltic and Arctic which reflects greater historical use of PBDEs in North America compared to Europe and greater industrialization of North America and Baltic countries compared to the Arctic. Regional patterns for other compounds were more complicated, and there were significant interactions among species, regions, body condition and age class. Lipid-normalized PBDE concentrations in harbor seal liver and blubber were similar, but HBBZ and many Dechloranes had higher concentrations in liver, indicating factors other than lipid dynamics affect the distribution of these compounds. The health implications of contamination by this mixture of compounds are of concern and require further research.

Legacy and novel brominated flame retardants in agricultural soils of eastern China (2011-2021): Concentration level, temporal trend, and health risk assessment

Polybrominated diphenyl ethers (PBDEs) and novel brominated flame retardants (NBFRs) have been extensively investigated in the terrestrial environment of China. However, little is known about how PBDEs and NBFRs burdens in agricultural soils altered over time. In this study, agricultural soils from different regions of China were collected from 2011 to 2021 to investigate the contamination levels and temporal variation of PBDEs and NBFRs. The concentrations of ∑₂₆PBDEs and ∑₅NBFRs ranged from 0.144 to 215 ng/g dry weight (d.w.) and 0.186-144 ng/g (d.w.), with a mean value of 9.27 ng/g (d.w.) and 8.22 ng/g (d.w.), respectively. Among PBDEs and NBFRs, BDE-209 and decabromodiphenylethane (DBDPE) were the most predominant compounds. The PBDE concentrations did not vary significantly during the past decade, whereas the lower brominated congeners increased with time (doubling times ranged from 5.46 to 8.56 years). Meanwhile, NBFR concentrations increased over time, with concentrations significantly higher in 2021, 2016, and 2013 than in 2011 (p < 0.05). Additionally, DBDPE, 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), and hexabromobenzene (HBB) had doubling times of 6.84, 11.2, and 7.37 years, respectively. Total organic matter (TOC) impacted the distribution and variation of PBDEs (particularly lower-brominated congeners), with soil organic matter (SOM)-sorption showing an increasing and then decreasing trend. Health risk assessment suggested that PBDEs and NBFRs did not pose non-carcinogenic risks to humans. Nevertheless, the long-term health risk of BFRs should be considered. Overall, this is the first study to comprehensively analyze the contamination burdens and temporal trends of PBDEs and NBFRs in Chinese agricultural soils over a long period, providing a fundamental basis for future BFR management.