The masking phenomenon of Per-/Polyfluoroalkyl substances on oxidative stress damage in Hydrilla verticillata under microplastic stress

Microplastics (MPs) and per- and polyfluoroalkyl substances (PFASs) are emerging aquatic pollutants characterized by toxicity, persistence, bioaccumulation, and resistance to degradation. Studies have found that MPs mask the oxidative stress damage of the PFASs on Hydrilla verticillata. Therefore, a grading evaluation system for the toxicological effect indicators of oxidative stress damage to Hydrilla verticillata under single and combined exposure to PFASs/PS-MPs, and a priority control list was developed in this study. The outcomes indicated >70 % of PFASs induced oxidative stress damage in Hydrilla verticillata under complex exposure to PS-MPs showed significant antagonistic contribution (antagonistic rate of 28.47 %). The carbon chain length and functional groups of PFASs were the main factors that affect the oxidative stress damage. Furthermore, results showed that the oxidative stress damage induced by PFASs/PS-MPs was most pronounced along the electron transport chain damage pathway. According to the priority control list established, two types of PFASs (i.e., GenX and PFBS) were found to have a higher masking risk. This is the first theoretical study to reveal the oxidative stress damage to Hydrilla verticillata caused by single exposure to PFASs and combined exposure to PFASs/PS-MPs, providing valuable reference and guidance for regulating the combined risk of pollutants to aquatic ecosystems.