Mollusks reveal the temporal-spatial variations and trophic transferring of ongoing bromophenols in the Bohai Sea, China

Abstract

Bromophenols (BrPs) are artificial precursors of some flame retardants and important substances with natural marine- or ocean-like flavors. This study studied the temporal variations and spatial distributions of BrPs in 150 mollusk samples (12 species) collected from 9 cities around the Bohai Sea from 2009 to 2019. Only 3 B.P. among the tested 19 congeners, 4-monobromophenol (4-mBrP), 2,4-dibromophenol (2,4-diBrP), and 2,4,6-tribromophenol (2,4,6-triBrP), were extensively detected with the detection frequency of 98.7 %, 86.7 %, and 98.0 %. The median concentration of 2,4,6-triBrP was 4.27 ng/g dw, followed by 4-mBrP (1.89 ng/g dw) and 2,4-diBrP (0.625 ng/g dw). The concentration of 3 detectable congeners, ∑3BrPs' ranged from 0.152 to 703 ng/g dw with a median value of 8.08 ng/g dw. The highest concentrations of ∑3BrPs and 2,4,6-triBrP all occurred in Rapana venosa (49.2 and 45.1 ng/g dw) which belongs to Muricidae (2009 to 2019) that was at a relatively higher trophic level among the tested mollusks. The concentration of BrPs in Gastropoda is much higher than that in Bivalvia. The median concentrations of 2,4-diBrP, 2,4,6-triBrP, and ∑3BrPs in Gastropoda and Bivalvia from Shandong Province were higher than those in other administrative divisions at the provincial level because of the large volume of BrP production and brominated flame retardants. Temporal variations in Gastropoda and Bivalvia from Weihai showed that concentrations of ∑3BrPs, 2,4,6-triBrP, 4-mBrP, and 2,4-diBrP declined slowly from 2009 to 2019. Our results provide a systematic insight into the environmental occurrence and fate of BrPs in the Bohai Sea.