Perfluoroalkyl substances (PFAS) are being increasingly reported as emerging contaminants in riverine and marine settings. This study investigated the contamination level and spatial distribution of PFAS within the depth profile of the Bohai and Yellow Seas. Moreover, the riverine flux of 11 selected PFAS in 33 rivers draining into the Bohai and Yellow Seas was estimated from previous studies in order to establish the relationship between riverine sources and marine sinks. The results showed that the Bohai and Yellow Seas were commonly contaminated with PFAS: total concentrations of PFAS in the surface, middle, and bottom zones ranged from 4.55 to 556 ng/L, 4.61-575 ng/ L, and 4.94-572 ng/L, respectively. The total riverine PFAS mass flux into the Bohai and Yellow Seas was estimated to be 72.2 t/y, of which 94.8% was carried by the Yangtze and Xiaoqing Rivers. As the concentration of short-chain PFAS begins to rise in seawater, further studies on the occurrence and fate of short-chain PFAS with special focus on effective control measures would be very timely.
17 PFAS including one emerging polyether substitute in water, sediment, and organisms were investigated from the South China Sea. Perfluorobutanoic acid (PFBA) was predominant in water, of which concentration ranged from ND to 10.26 ng/L, with a mean of 5.21 ng/L. Similar to sediment and organisms, PFBA was the substance with the highest concentration detected among PFAS. This result seemingly indicated that use of short-chain PFAS as substitutes for long-chain PFAS in recent years. Trophic magnification factors (TMFs) of PFAS were estimated in the marine food web. TMFs >1 was observed only in perfluorooctane sulfonic acid (PFOS), indicating a biomagnification potential of PFOS in the given ecosystem. The estimated daily intake (EDI) of PFOS and PFOA were most prevalent in mollusk, whereas the EDI of PFBA was greater in fish and shrimp. The hazard ratio (HR) were lower than 1, which suggests that PFAS via seafood consumption would not cause significant health risk to local residents.
Bullfrogs are regarded as the indicator specie to assess ecosystem and human health risk because they are living in a complex environment utilizing both aquatic and terrestrial environments, bioaccumulate contaminants, and increase risk for human health. Bullfrog is one popular aquatic product providing high protein and tasty cuisine, however, its risk-benefit of PFASs and nutrient after cooked has not been well understood. PFAS in wild bullfrogs (mean: 44.17 ng/g·dw) were generally higher than those in cultured bullfrogs (mean: 31.87 ng/g·dw). Novel PFAS performed higher detection level and accumulation in wild bullfrogs than those cultured. All cooking methods can reduce PFAS in edible tissues while enhance nutritive value significantly compared to raw bullfrogs.

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