Antagonistic toxicity of nanoplastics and perfluorobutanoic acid to the behavior of black rockfish (Sebastes schlegelii)

The combined effect of per- and polyfluoroalkyl substances (PFASs) and nanoplastics (NPs) on fish behavior is unclear. In the present study, PS NPs (65 nm, 1 mg/L) or perfluorobutyric acid (PFBA, 10 μg/L) alone caused behavioral disorders (e.g., reduced numbers of floats and sinks, numbers of chases, and swimming speed) of Sebastes schlegelii upon water exposure (14 days), while co-exposure of PS NPs and PFBA reduced the severity of behavioral disorders compared to PFBA alone. Additionally, PS NPs or PFBA significantly increased superoxide dismutase activity and malondialdehyde content, and decreased catalase activity of gut. However, this oxidative stress significantly reduced in the presence of both PS NPs and PFBA in comparison with PFBA alone. Moreover, PS NPs or PFBA also damaged the intestinal villi and epithelium. Notably, PFBA significantly decreased the muscular thickness and length-to-width ratio of intestinal villi, and reduced the diversity and network complexity of gut microbiota, causing more severe intestinal damage. Interestingly, PS NPs alleviated the intestinal damage and increased the gut microbial abundance induced by PFBA, thereby mitigating the toxic effect of PFBA on fish behavior. This study is essential for understanding the ecological and health risks of NPs and PFASs in aquatic environments.