Temporal Trends and Suspect Screening of Halogenated Flame Retardants and Their Metabolites in Blubbers of Cetaceans Stranded in Hong Kong Waters during 2013–2020

Abstract

Halogenated flame retardants (HFRs) are a large class of chemical additives intended to meet flammability safety requirements, and at present, they are ubiquitous in the environment. Herein, we conducted the target analysis and suspect screening of legacy and novel HFRs and their metabolites in the blubber of finless porpoises (Neophocaena phocaenoides; n = 70) and Indo-Pacific humpback dolphins (Sousa chinensis; n = 35) stranded in Hong Kong, a coastal city in the South China Sea, between 2013 and 2020. The average concentrations of total target HFRs (ΣHFRs) were 6.48 × 10 3 ± 1.01 × 10 4 and 1.40 × 10 4 ± 1.51 × 10 4 ng/g lipid weight in porpoises and dolphins, respectively. Significant decreasing temporal trends were observed in the concentrations of tetra-/penta-/hexa-bromodiphenyl ethers (tetra-/penta-/hexa-BDEs) in adult porpoises stranded from 2013−2015 to 2016−2020 (p < 0.05), probably because of their phasing out in China. No significant difference was found for the concentrations of decabromodiphenyl ether and hexabromocyclododecane, possibly due to their exemption from the ban in China until 2025 and 2021, respectively. Eight brominated compounds were additionally identified via suspect screening. A positive correlation was found between the concentrations of tetra-BDE and methyl-methoxy-tetra-BDE (Me-MeO-tetra-BDE) (p < 0.05), indicating that the metabolism of tetra-BDE may be a potential source of Me-MeO-tetra-BDE in marine mammals.

Endocrine-Disrupting Chemical Exposure Induces Adverse Effects on the Population Dynamics of the Indo-Pacific Humpback Dolphin

“…One of the most significant threats to this population arises from the accumulation of pollutants. Significant concentrations of various EDCs, including polybrominated diphenyl ethers (PBDEs), bisphenols (BPs), alkylphenols (APs), per- and polyfluoroalkyl substances (PFASs), polychlorinated biphenyls (PCBs), triclosan, dichlorodiphenyltrichloroethane (DDT), Cr, and As, have been detected in PRE humpback dolphins, surpassing global averages. − Although there are assumed correlations between EDCs and reproductive toxicity, immunotoxicity, developmental toxicity, and neurotoxicity, ,, there are limited empirical studies that explicitly address the impacts on this humpback dolphin population.…”