Challenges and persistence of contact lenses in wastewater treatment plants: Environmental implications

Contact lens Degradation Wastewater treatment plants Environmental impact Microplastics
["Alves, Rita Martins-","Machado, Ana Vera","Cassio, Fernanda","Lira, Madalena"] 2025-09-01 期刊论文
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Contact Lens (CLs) are often disposed of via toilet or sinks, ending up in the wastewater treatment plants(WWTPs). Millions of CLs enter WWTPs worldwide each year in macro and micro sizes. Despite WWTPs'ability to remove solids, CLs can persist and potentially contaminate watercourses and soils. This study evaluates whether different CLs degrade in WWTP aeration tanks. Six daily CLs (Nelfilcon A,Delefilcon A, Nesofilcon A, Stenfilcon A, Narafilcon A, Somofilcon A) and four monthly CLs (Lotrafilcon B,Comfilcon A, Senofilcon A, and Samfilcon A) were immersed in aeration tanks for twelve weeks. Theirphysical and chemical properties, including water content (WC), refractive index (RI), chemical prop-erties (Fourier Transform Infrared Spectroscopy), and mechanical properties were assessed. Results show that all CLs maintained their physical appearance after 12 weeks. Neither Nelfilcon A norNarafilcon A exhibited significant changes in WC and RI, (p>0.05, Tukey test), while other daily lensesshowed variations in at least one parameter. Among monthly CLs, only Senofilcon A showed significant differences in both WC (p<0.001, Tukeytest) and RI (p<0.0001, Tukey test). No differences in Young's modulus were observed for any lenses(p>0.05 Tukey test). However, Somofilcon A displayed significant changes in stress at break (p<0.0001,Tukey test), and Elongation at Break (p<0.05, Tukey test). No changes were found in the chemicalstructure of any CLs suggesting that twelve weeks in WWTP aeration tanks is insufficient for CLsdegradation. Thesefindings highlight CLs as a potential emerging pollutant, emphasizing their persis-tence in sludge or migration into watercourses and soils (c) 2025 The Authors. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. Thisis an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
来源平台:EMERGING CONTAMINANTS