Effect of potential microplastics in sewage effluent on Nile Tilapia and photocatalytic remediation with zinc oxide nanoparticles

• Published in: Environmental pollution (1987) 2023-09, Vol.332, p.121946-121946, Article 121946
• Main Authors: Alanazi, Manal Qayyadh, Virk, Promy, Alterary, Seham Soliman, Awad, Manal, Ahmad, Zubair, Albadri, Abdulrehman M., Ortashi, KalidM, Ahmed, Mohieldeen Mahgoub A., Ali Yousef, Mohamed Ismail, Elobeid, Mai, Al-Qahtani, Ebtesam Abdullah
• Format: Article
• Language: English
• Subjects: Microplastics; Neurotoxicity; Nile tilapia; Oxidative stress; Photodegradation; Sewage effluent; Zinc oxide nanoparticles
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2023.121946

The aim of the present study was a qualitative assessment of potential microplastics (MPs) in the sewage effluent collected from a local sewage treatment plant located in Riyadh City, Saudi Arabia. The composite samples of domestic sewage effluent were subjected to UV (ultraviolet) light-induced zinc oxide nanoparticles (ZnONPs) mediated photocatalysis. The first phase of the study included the synthesis of the ZnONPs with an extensive characterization. The synthesized nanoparticles were 220 nm in size with a characteristic spherical/hexagonal shape. These NPs were then used at three different concentrations (10 mM, 20 mM, and 30 mM) for the UV light-induced photocatalysis. A shift in the Raman spectra on photodegradation mirrored the surface changes of the functional groups shown by the FTIR spectra; presence of functional groups containing oxygen and C–C bonds associated with oxidation and chain scission. SEM micrographs showed photodegraded particles. Complementary elemental maps from the EDS analysis showed the presence of C, O, and Cl suggesting the potential presence of MPs. The O/C ratio was used to assess potential oxidation degree. In addition, an evaluation of the toxicological effects of the potential MPs in the sewage effluent on Nile tilapia (Oreochromis niloticus) exposed to the effluent at two concentrations (50% and 75%) elicited a marked response in the endpoints evaluated; EROD activity, MDA (malondialdehyde), 8-oxo-2′-deoxyguanosine levels in and AChE (acetylcholinesterase) activity in the brain. Thus, the key results provide new insights into the use of clean technologies to combat global MP pollution in aquatic ecosystems. [Display omitted] •Spectroscopy with SEM/EDS revealed the C,O elemental maps in the plastic matrix.•ZnO nanoparticles demonstrated photodegradation of the potential microplastics.•The biological endpoints showed a marked alleviation of the toxicological effects.