Transcriptomic and behavioural data reveal elevated neurotoxic effects of PCB-153 when co-exposed with polystyrene nanoplastics in zebrafish larvae

Nanoplastics (NPs) and persistent organic pollutants such as polychlorinated biphenyls (PCBs) are ubiquitous aquatic environment pollutants and might harm the ecosystem. The coexistence of these pollutants underscores the need to study their combined toxicity. NPs are known to cross biological membranes and act as a vectors to transport other pollutants, whereas PCBs are known for their long bioaccumulation and biomagnification. The present is the first comprehensive study focusing on the combined toxicity of polystyrene NPs and PCB-153 using physiological (development, heart rate, respiration), behavioural (swimming behaviour) and molecular (transcriptome) endpoints in zebrafish larvae. The results indicate that solo and co-exposure to PCB with NPs had significantly affected the development and respiration in zebrafish larvae. The transcriptomic results revealed that PCB exposure had significantly affected critical neurogenic pathways. In contrast, the co-exposure of NPs and PCB generated multi-faceted toxicity and suppressed neurobehavioural, immune-related and detoxification pathways. This effect was also seen in the swimming behaviour of zebrafish larvae, where the animals showed significant hyperlocomotory swimming behaviour. The study highlights the complex interplay between NPs and PCBs, revealing broader and intensified toxic effects in co-exposure scenarios.