Hazardous potential assessment of airborne and foodborne polyvinyl alcohol and polyhydroxyalkanoates nanoplastics: Comparison with polyvinyl chloride nanoplastics

Nanoplastics (NP) are emerging pollutants in the environment. Bio-based materials are attracting increasing scientific attention as their application may alleviate the environmental pollution caused by conventional plastics. However, their hazardous potentials still need to be investigated. In this study, multi-omics approaches were carried out to explore and compare the conventional polyvinyl chloride (PVC), bio-based polyhydroxyalkanoates (PHA) and water-soluble polyvinyl alcohol (PVA) NP for their lung and liver toxicity in mice. Airborne PVC NP could cause nasal and lung microbial dysbiosis, lung and serum metabolic disruption, liver transcriptomic dysregulation, and result in lung and liver toxicity. In contrast, airborne PHA and PVA NP could induce nasal and lung microbial alterations, lung and serum metabolic disruption, liver transcriptomic disturbance, and lead to mild lung toxicity. As for foodborne PHA, PVA and PVC NP, they all could induce gut microbial dysbiosis, gut and serum metabolic disruption. Foodborne PVC NP could cause similar transcriptomic alterations and greater histological changes in liver compared to PHA NP, while foodborne PVA NP could induce transcriptomic disturbance but not apparent pathology in liver. Among the various alterations, multiple lung pathways (e.g., "renal cell carcinoma") and liver pathways (e.g., "arachidonic acid metabolism") were commonly greatly enriched by airborne PHA and PVA NP but not PVC NP, while multiple liver pathways (e.g., "pancreatic secretion") were commonly largely intensified by foodborne PVC and PHA NP but not PVA NP, aligning with the histological differences between groups. The relevant findings suggest PVA and PHA NP have lower lung and liver toxicity than PVC NP. The results could also benefit the clinical diagnoses of liver and lung toxicity induced by airborne and foodborne PVC, PVA and PHA NP.