Trophic transfer and interfacial impacts of micro(nano)plastics and per-and polyfluoroalkyl substances in the environment.

Both micro(nano)plastics (MNPs) and per-and polyfluoroalkyl substances (PFAS) possessed excellent properties and diverse applications, albeit gained worldwide attention due to their anthropogenic, ubiquitous, degradation resistant nature and a wide variety of ecological and human health impacts. MNPs and PFAS discharged from discrete sources and extensively bioaccumulated in the food chain through trophic transfer and their long-distance transport potential assist in their dispersal to pristine but vulnerable ecosystems such as Antarctica. They inevitably interacted with each other in the environment through polarized N-H bond, hydrogen bond, hydrophobic interaction, and weak bond energies such as Van der Waals, electrostatic, and intramolecular forces. During co-exposure, they significantly impact the uptake and bioaccumulation of each other in exposed organisms, which may increase or decrease their bioavailable concentration. Hence, this review compiles the studies on the co-occurrence and adsorption of PFAS and MNPs in the environment, their trophic transfer, combined in vivo and in vitro impacts, and factors influencing the MNP-PFAS interface. A significant proportion of studies were conducted in China, Europe, and the US, while studies are rare from other parts of the world. Freshwater and marine food chains were more prominently investigated for trophic transfers compared to terrestrial food chains. The most notable in vivo effects were growth and reproductive impairment, oxidative stress, neurotoxicity and apoptosis, DNA damage, genotoxicity and immunological responses, behavioral and gut microbiota modifications, and histopathological alterations. Cellular uptake of PFAS and MNPs can impact cell survival and proliferation, photosynthesis and membrane integrity, ROS generation and antioxidant responses, and extracellular polymeric substances (EPS) release in vitro. MNP characteristics, PFAS properties, tissue and species-dependent distribution, and environmental medium properties were the main factors influencing the PFAS and MNP nexus and associated impacts. Last but not least, gaps and future research directions were highlighted to better understand the interplay between these critical persistent chemicals.

Concurrent impacts of polystyrene nanoplastic exposure and Aeromonas hydrophila infection on oxidative stress, immune response and intestinal microbiota of grass carp (Ctenopharyngodon idella).

Research has demonstrated that polystyrene nanoplastics (PS-NPs) can have adverse effects on the immune responses of fish. NPs have the potential to increase the likelihood of infections in fish by pathogenic bacteria, such as the opportunistic pathogen Aeromonas hydrophila, potentially increasing the virulence of pathogenic bacteria infections in fish. The concurrent effects of PS-NPs and A. hydrophila on grass carp intestinal tissues were assessed by exposing grass carp to different concentrations of PS-NPs (10 µg/L, 100 µg/L, 1000 µg/L) after infection with A. hydrophila. As the concentration of PS-NPs in the exposure and the duration of A. hydrophila infection both escalated, intestinal tissues showed damage in the form of disordered breakage of intestinal villi, thinning of the intestinal wall, and reduced necrosis of the cells in the annulus muscle layer. The AHS-PS100 group and AHS-PS1000 group exhibited a substantial rise in the function of CAT, SOD, GST, and MPO, as well as increased MDA content and elevated ROS levels (p < 0.05). In the AHS-PS1000 group, the expression levels of IL-6, IL-8, IL-10, IL-1ß, TNF-α, and IFN-γ2 experienced a significant upsurge (p < 0.05). In addition, exposure to PS-NPs and A. hydrophila infection induced modifications in the microbial composition of the grass carp gut, affecting both phylum and genus taxonomic categories. Moreover, an increase in the abundance of Spirochaetota and Bacteroidota was observed not only in the positive control group but also in the AHS-PS100 and AHS-PS1000 groups following A. hydrophila infection. These experimental results indicate that PS-NPs exposure will aggravate the oxidative stress and inflammatory response of grass carp intestinal tissue in response to A. hydrophila infection, and lead to changes in intestinal microbial diversity and abundance. Overall, this study provides valuable hints on the potential concurrent effects of PS-NPs exposure on grass carp's response to A. hydrophila infection.