Brominated flame retardants in mangrove sediments of the Pearl River Estuary, South China: Spatial distribution, temporal trend and mass inventory

• PBDEs, DBDPE and BTBPE were determined in mangrove sediments of the PRE.
• The highest levels of BFRs were found in mangrove sediments from Shenzhen.
• BFRs in mangrove sediments were dominated by PBDEs, followed by DBDPE and BTBPE.
• Levels of BFRs in cores showed an increasing trend from the bottom to top layers.
• Mangrove sediments are important reservoirs for BFRs.

Sediments were collected from three mangrove wetlands in the Pearl River Estuary (PRE) of South China to investigate spatial and temporal distributions of polybrominated diphenyl ethers (PBDEs), decabromodiphenyl ethane (DBDPE) and 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE). Concentrations of ΣPBDEs, DBDPE and BTBPE in mangrove sediments of the PRE ranged from 1.25–206, 0.364–34.9, and not detected–0.794 ng g−1 dry weight, respectively. The highest concentrations of ΣPBDEs, DBDPE and BTBPE were found at the mangrove wetland from Shenzhen, followed by Zhuhai and Guangzhou, showing the dependence on the proximity to urban areas. PBDEs were the predominant brominated flame retardants (BFRs) in mangrove sediments. The concentrations of ΣPBDEs, DBDPE and BTBPE in sediment cores showed an increasing trend from the bottom to top layers, reflecting the increasing usage of these BFRs. The inventories of ΣPBDEs, DBDPE and BTBPE in mangrove sediments were 1962, 245, and 4.10 ng cm−2, respectively. This is the first study to report the occurrence of DBDPE and BTBPE in mangrove ecosystems.