Avobenzone and nanoplastics affect the development of zebrafish nervous system and retinal system and inhibit their locomotor behavior

The use of cosmetics is growing with each passing day, arousing widespread attention to their ingredients. Avobenzone (AVO) and nanoplastics (NPs) are typical ingredients in cosmetics, which coexist in the aquatic environment and have a combined effect on aquatic organisms. In this study, the accumulation of AVO and NPs in zebrafish larvae and effects on gene expression and enzymatic activity related to nervous functions, and locomotor behavior were investigated. AVO and NPs accumulated continuously in zebrafish, and the combined exposure enhanced AVO accumulation. After recovery, the accumulated concentrations of AVO and NPs in zebrafish remained unchanged, suggesting that AVO and NPs could not be eliminated in 72 h. The genes regulated nervous system development were affected mainly by AVO exposure, while the genes regulated retinal system development were affected by NPs exposure. Single and combined exposures of AVO and NPs affected the activities of acetylcholinesterase and antioxidant enzymes in zebrafish, and superoxide dismutase activity could not return to normal level after 72 h of recovery period. The locomotor activity of zebrafish larvae was significantly inhibited by AVO and NPs, which might be related to the alterations in functions of nervous system development and retinal system development as well as the interference of neurotransmitter system and antioxidant system.