Synthetic Phenolic Antioxidants and Their Metabolites in Mollusks from the Chinese Bohai Sea: Occurrence, Temporal Trend, and Human Exposure.

Synthetic phenolic antioxidants (SPAs) are a group of chemicals widely used in various daily necessities and industrial supplies. Little is known about the occurrence and bioaccumulation potential of SPAs in marine biota. In this study, five commonly used SPAs and their four metabolites were detected in mollusk samples (n = 274) collected from the Chinese Bohai Sea during 2006-2016 and the spatiotemporal distribution and bioaccumulation of SPAs in mollusks were examined. The concentrations of 2,6-di-tert-butyl-4-hydroxytoluene (BHT) ranged from 383 to 501000 ng/g (geometric mean: 3450 ng/g), accounting for 79.4% of the total concentrations of SPAs and their metabolites (Sigma 9SPAs). The mollusk species, Rapana venosa (RAP), contained higher levels of BHT than other species, suggesting that Rap could be used as a potential bioindicator for monitoring of the BHT pollution in the investigated region. The Sigma 9SPAs concentrations in mollusks gradually increased with years and a significant positive correlation (r = 0.900, p < 0.05) was found between Sigma 9SPAs concentration and trophic level of the mollusks. The trophic magnification factor value of Sigma 9SPAs was calculated as 16.1, suggesting a high biomagnification potential of SPAs in mollusks in the Chinese Bohai Sea. The estimated daily intake of Sigma 9SPAs through dietary ingestion of mollusks was up to 602 and 789 ng/kg bw/day for adults and children and teenagers, respectively. The principal component analysis result suggests that there exists a common source for three gallates (OG, DG, and PG), and BHT metabolites in mollusks were mainly derived from degradation of BHT. This is the first study to report the occurrence and bioaccumulation potentials of SPAs and their metabolites in invertebrate species from coastal marine environments.