Centre for Environmental and Marine Studies (CESAM) and Department of Biology, University of Aveiro, 3810-19, Aveiro, Portugal; Universidade Católica Portuguesa, Faculty of Dental Medicine (FMD), Center for Interdisciplinary Research in Health (CIIS), 3504-505, Viseu, Portugal.
Centre for Environmental and Marine Studies (CESAM) and Department of Biology, University of Aveiro, 3810-19, Aveiro, Portugal.
Chemosphere. 2024 Aug;361:142421. doi: 10.1016/j.chemosphere.2024.142421. Epub 2024 May 24.
Research has demonstrated the presence of viruses in wastewater (WW), which can remain viable for a long period, posing potential health risks. Conventional WW treatment methods involving UV light, chlorine and ozone efficiently reduce microbial concentrations, however, they produce hazardous byproducts and microbial resistance that are detrimental to human health and the ecosystem. Hence, there is a need for novel disinfection techniques. Antimicrobial Photodynamic Inactivation (PDI) emerges as a promising strategy, utilizing photosensitizers (PS), light, and dioxygen to inactivate viruses. This study aims to assess the efficacy of PDI by testing methylene blue (MB) and the cationic porphyrin TMPyP as PSs, along a low energy consuming white light source (LED) at an irradiance of 50 mW/cm, for the inactivation of bacteriophage Phi6. Phi6 serves as an enveloped RNA-viruses surrogate model in WW. PDI experiments were conducted in a buffer solution (PBS) and real WW matrices (filtered and non-filtered). Considering the environmental release of the treated effluents, this research also evaluated the ecotoxicity of the resulting solution (post-PDI treatment effluent) on the model organism Daphnia magna, following the Organisation for Economic Cooperation and Development (OECD) immobilization technical 202 guideline. Daphnids were exposed to WW containing the tested PS at different concentrations and dilutions (accounting for the dilution factor during WW release into receiving waters) over 48 h. The results indicate that PDI with MB efficiently inactivated the model virus in the different aqueous matrices, achieving reductions superior to 8 log PFU/mL, after treatments of 5 min in PBS and of ca. 90 min in WW. Daphnids survival increased when subjected to the PDI-treated WW with MB, considering the dilution factor. Overall, the effectiveness of PDI in eliminating viruses in WW, the fading of the toxic effects on daphnids after MB' irradiation and the rapid dilution effect upon WW release in the environment highlight the possibility of using MB in WW PDI-disinfection.
研究已经证明了病毒在废水中（WW）的存在，这些病毒可以在很长一段时间内保持存活，从而构成潜在的健康风险。传统的 WW 处理方法，如紫外线、氯和臭氧，能够有效地降低微生物浓度，但它们会产生有害的副产物和微生物抗性，对人类健康和生态系统造成危害。因此，需要新型的消毒技术。光动力抗菌灭活（PDI）作为一种有前途的策略，利用光敏剂（PS）、光和氧气来灭活病毒。本研究旨在评估 PDI 的效果，方法是使用亚甲蓝（MB）和阳离子卟啉 TMPyP 作为 PS，在低能耗的白光光源（LED）下，辐照度为 50 mW/cm，对噬菌体 Phi6 进行灭活。Phi6 是 WW 中包膜 RNA 病毒的替代模型。在缓冲溶液（PBS）和真实的 WW 基质（过滤和未过滤）中进行了 PDI 实验。考虑到处理后废水的环境释放，本研究还按照经济合作与发展组织（OECD）的固定化技术 202 指南，评估了处理后溶液（PDI 后处理废水）对模式生物大型蚤的生态毒性。大型蚤暴露在含有测试 PS 的 WW 中，浓度和稀释度不同（考虑 WW 释放到受纳水中的稀释因子），持续 48 小时。结果表明，PDI 用 MB 可以有效地在不同的水基质中灭活模型病毒，在 PBS 中处理 5 分钟和 WW 中处理约 90 分钟后，达到超过 8 log PFU/mL 的减少。考虑到稀释因子，当大型蚤暴露于含有 MB 的 PDI 处理 WW 时，其存活率增加。总的来说，PDI 在消除 WW 中的病毒、MB 辐照后对大型蚤的毒性影响消退以及 WW 释放到环境中的快速稀释效果，突出了在 WW PDI 消毒中使用 MB 的可能性。
