Temporal and seasonal variation and ecological risk evaluation of flame retardants in seawater and sediments from Bohai Bay near Tianjin, China during 2014 to 2017

Seawater and sediment samples were collected from 2014 to 2017 at Bohai Bay near Tianjin, China. The median concentration of ΣOPFRs was 2202 ng/l in the seawater from 2017. ΣAlkyl-OPFRs was the predominant constitution in the seawater with a median contribution of nearly 80%, and ΣCl-OPFRs was the major component in the sediment. Regarding BFRs, BDE-209 was the principal one in the sediment. The levels of TEP, TCEP and TBEP in sediments displayed significantly seasonal variations. The summer concentration of TEP was higher than that in both the spring and autumn, and concerning TCEP and TBEP, their lowest concentration occurred in summer. The concentration of ΣOPFRs experienced a rapid increasing during 2014–2016 due to more emissions of OPFRs. The ecological risk evaluation of OPFRs and BFRs suggested a moderate and high risk to the investigated marine region under the high exposure scenario, respectively.