摘要
Engineered nanoparticles(ENPs)threaten the environment through wastewater discharging.Generally,constructed wetlands(CWs)are efficient methods for ENPs removal.However,the biotoxicity of ENPs on plants in CWs is unclear.Here,we investigated the distribution and bio-impacts of different ENPs(Ag NPs,TiO_(2) NPs,and CeO_(2) NPs)in plants under 5-and 60-day exposure to 1 and 50 mg/L concentrations.Results showed that ENPs appeared in the vascular bundle and mesophyll cell space,which induced the variation in antioxidase activities(e.g.,superoxide dismutase[SOD],peroxidase[POD],and catalase[CAT]activities)as well as overproduction of malondialdehyde(MDA).Additionally,Ag NPs inhibited photosynthesis rate and root activity during two exposure phases.CeO_(2) NPs had positive and negative impacts on plants in 5-and 60-day exposure,respectively.Inversely,TiO_(2) NPs enhanced photosynthesis and root activity under 60-day exposure.Finally,the contents of the C,N,and P elements in plants fluctuated in response to ENPs stress.All results have a positive correlation with the wetland performance under ENPs exposure except for TiO_(2) NPs treatment.Overall,our study systematically reveals aquatic plants'responses to ENPs and provides a reference for building ecological treatment systems to purify wastewater containing ENPs.
基金
supported by the National Natural Science Foundation of China(Grant No.51708056)
the National Major Project of Pollution Control and Treatment Science and Technology(Grant No.2017ZX07401003-4)
Chongqing Talents Plan for Young Talents(No.CQY201905062)。