The interfacial interaction between Dechlorane Plus (DP) and polystyrene nanoplastics (PSNPs): An overlooked...

As pollution has attracted attention due to its wide distribution. An environmental concern that may be overlooked is that NPs additives are easily released into the environment due to their physical combination with NPs. However, the knowledge gaps still exist about the interfacial reactions of NPs and the additives (e.g. flame retardants) and the joint ecological effect. In the present study, fourier transform infrared (FTIR) spectrometer coupled with 2D correlation spectroscopy (2D-COS) analysis revealed the interfacial reactions between polystyrene nanoplastics (PSNPs) and Dechlorane Plus (DP). Results showed that carbon‑oxygen bonds and carbon‑chlorine bonds were the important binding sites during adhesion and DP could reduce the colloidal stability. Single and joint ecological effects of PSNPs and DP on the microalgae Chlorella vulgaris were further deliberated. Reduced photosynthetic efficiency (reduced F_v/F_m by 0.03 %), higher growth inhibition (16.15 %) and oxidative damage (increased ROS by 152 %) were observed in algae under co-exposure. Notably, DP could significantly increase the attachment of PSNPs to the surface of the algae. Metabolomics further revealed that co-exposure significantly down-regulated amino acid metabolism and tricarboxylic acid cycle (TCA) cycle, and up-regulated fatty acid metabolism. The present study provides new insights into the risk assessment of NPs in aquatic environment by investigating the interfacial reaction mechanism and combined ecotoxicity of NPs and additives.