The vector effects of microplastics (MPs) in natural marine environments and their contribution to polycyclic aromatic hydrocarbon (PAH) bioaccumulation in fish are still unknown. This study, therefore, aimed to evaluate the effects of MPs on carrying PAHs under conditions close to the actual marine environments. The PAH content sorbed onto MPs from seawater positively correlated with the octanol/water partition coefficient (log KOW) in both polyethylene and polystyrene MPs. The desorption rate constant (k2) of PAHs sorbed onto MPs from seawater in the digestive tract was calculated using two marine teleost fish in an in vitro desorption experiment. A negative correlation was observed between the log KOW and k2 of the PAHs. The PAHs with larger log KOW and lower water solubility are easier to sorb onto MPs and less likely to desorb in the digestive tract of marine fish species. The estimation of PAH uptake into the fish body using the k2 of three selected PAHs (phenanthrene, pyrene, and chrysene) indicated that >95 % of the chemicals were uptaken from seawater via gills. It was presumed that there was an additional uptake of PAHs into the fish body (vector effect) due to desorption from MPs in the digestive tract when marine fish ingested MP that was sorbed and concentrated with PAHs. The degree of uptake was, however, much lower than that from seawater via gills. The vector effect of PAHs by MPs in the actual sea may be negligible, and the risk is presently considered to be low.

中文翻译：

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红鲷 （Pagrus major） 和木乃伊鱼 （Fundulus heteroclitus） 消化道中聚乙烯微塑料中解吸的多环芳烃的吸收估计


微塑料 （MP） 在自然海洋环境中的媒介效应及其对鱼类中多环芳烃 （PAH） 生物积累的贡献仍然未知。因此，本研究旨在评估 MP 在接近实际海洋环境的条件下对携带 PAH 的影响。从海水吸附到 MP 上的 PAH 含量与聚乙烯和聚苯乙烯 MP 中的辛醇/水分配系数 （log KOW） 呈正相关。在体外解吸实验中使用两条海洋硬骨鱼计算从消化道海水吸附到 MP 上的 PAHs 的解吸速率常数 （k2）。观察到 PAHs 的 log KOW 和 k2 之间呈负相关。对数 KOW 较大且水溶性较低的 PAHs 较容易吸附在 MPS 上，且较不容易在海鱼的消化道中解吸。使用三种选定的 PAH（菲、芘和温烯）的 k2 估计鱼体内的 PAH 吸收量表明，>95% 的化学物质是通过鳃从海水中吸收的。据推测，当海洋鱼类摄入被 PAH 吸附和浓缩的 MP 时，由于 MP 在消化道中的解吸，PAH 会额外吸收到鱼体内（媒介效应）。然而，吸收程度远低于从海水中通过鳃吸收的程度。MP 在实际海洋中 PAH 的媒介效应可能可以忽略不计，目前认为风险较低。