Nofima, Muninbakken 9-13, Breivika, 9019 Tromsø, Norway.
Department of Environmental Science, Aarhus University, 4000 Roskilde, Denmark.
Int J Mol Sci. 2023 Jun 19;24(12):10326. doi: 10.3390/ijms241210326.
Omnipresent microplastics (MPs) in marine ecosystems are ingested at all trophic levels and may be a vector for the transfer of persistent organic pollutants (POPs) through the food web. We fed rotifers polyethylene MPs (1-4 µm) spiked with seven congeners of polychlorinated biphenyls (PCBs) and two congeners of polybrominated diphenyl ethers (PBDEs). In turn, these rotifers were fed to cod larvae from 2-30 days post-hatching (dph), while the control groups were fed rotifers without MPs. After 30 dph, all the groups were fed the same feed without MPs. Whole-body larvae were sampled at 30 and 60 dph, and four months later the skin of 10 g juveniles was sampled. The PCBs and PBDEs concentrations were significantly higher in MP larvae compared to the control larvae at 30 dph, but the significance dissipated at 60 dph. Expression of stress-related genes in cod larvae at 30 and 60 dph showed inconclusive minor random effects. The skin of MP juveniles showed disrupted epithelial integrity, fewer club cells and downregulation of a suite of genes involved in immunity, metabolism and the development of skin. Our study showed that POPs were transferred through the food web and accumulated in the larvae, but that the level of pollutants decreased once the exposure was ceased, possibly related to growth dilution. Considering the transcriptomic and histological findings, POPs spiked to MPs and/or MPs themselves may have long-term effects in the skin barrier defense system, immune response and epithelium integrity, which may potentially reduce the robustness and overall fitness of the fish.
海洋生态系统中无处不在的微塑料（MPs）在各个营养级都被摄入，并可能成为通过食物网转移持久性有机污染物（POPs）的载体。我们用七种多氯联苯（PCBs）和两种多溴联苯醚（PBDEs）同型物污染的轮虫喂养幼鳕鱼，然后再用这些轮虫喂养 2-30 日龄（dph）的幼鳕鱼，而对照组则用未污染 MPs 的轮虫喂养。30 dph 后，所有组都用不含 MPs 的相同饲料喂养。在 30 和 60 dph 时采集整尾幼虫样本，四个月后采集 10 克幼鱼的皮肤样本。与对照组相比，MP 幼虫在 30 dph 时体内的 PCB 和 PBDE 浓度明显更高，但在 60 dph 时这种差异不再显著。30 和 60 dph 时，鳕鱼幼虫的应激相关基因表达显示出无定论的小随机效应。MP 幼鱼的皮肤显示出上皮完整性受损、 klub 细胞减少以及参与免疫、代谢和皮肤发育的一系列基因下调。我们的研究表明，POPs 通过食物网传递并在幼虫中积累，但一旦停止暴露，污染物水平就会下降，这可能与生长稀释有关。考虑到转录组学和组织学发现，MPs 上的污染物和/或 MPs 本身可能对皮肤屏障防御系统、免疫反应和上皮完整性产生长期影响，这可能会降低鱼类的健壮性和整体适应性。
