Whether the hybridization of polystyrene, polyethylene, and polypropylene microplastics impacts aquatic carbon leakage from water hyacinth: A case study considering per(poly)fluorocarboxylicacid cocontamination

Microplastics (MPs), per(poly)fluoroalkyl substances (PFASs), and their co-occurrence have reshaped aquatic ecosystems in various ways, particularly by affecting floating macrophytes and their associated aquatic carbon. The release of aquatic carbon is crucial for shaping the microenvironment, enhancing eco-remediation efficiency, and managing greenhouse gases, in the water column associated with floating macrophytes. This study focused on the impact of MP components on this process and further considered the co-contamination scenarios involving perfluorooctanoic acid (PFOA) and hexafluoropropylene oxide dimer acid (GenX). Hydroponics simulation experiments using Eichhornia crassipes (E. crassipes) revealed that, after 14-day exposure, the released amount of aquatic carbon increased with higher degrees of MP hybridization. The similar trends were observed under PFOA/GenX co-pollution. Compared with the pollution-free group, the contamination treatments caused significant heterogeneity in the UV–visible spectra and fluorescence matrices of the dissolved organic matter (DOM) released by E. crassipes. Two key fluorescent components of DOM were identified via parallel factor analysis. Their relative proportions shifted to varying degrees under PFAS contamination and further modified by MP hybridization, indicating alterations in DOM transformation. According to Mantel test, among environmental impact factors selected in this study, MP hybridization did not show a relatively significant direct association with overall DOM properties, whereas colloid size exhibited strong correlations with DOM characteristics. However, specifically, in the presence of PFOA/GenX, MP hybridization tended to induce E. crassipes to release DOM with smaller molecular size and lower aromaticity. This study enhances strategic understanding of macrophyte-based phytoremediation, lacustrine management, and carbon sequestration, particularly under complex pollution scenarios.