Vacuum ultraviolet irradiation for reduction of the toxicity of wastewater towards mammalian cells: Removal mechanism, changes in organic compounds, and toxicity alternatives

Liu He; Wen-Long Wang; De-Xiu Wu; Shao-Yu Wang; Xiao Xiao; He-Qing Zhang; Min-Yong Lee; Qian-Yuan Wu

Environment International (Dec 2023)

Vacuum ultraviolet irradiation for reduction of the toxicity of wastewater towards mammalian cells: Removal mechanism, changes in organic compounds, and toxicity alternatives

Liu He,
Wen-Long Wang,
De-Xiu Wu,
Shao-Yu Wang,
Xiao Xiao,
He-Qing Zhang,
Min-Yong Lee,
Qian-Yuan Wu

Affiliations

Liu He: Shenzhen Key Laboratory of Ecological Remediation and Carbon Sequestration, Environmental Protection Key Laboratory of Microorganism Application and Risk Control, Institute of Environment and Ecology, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, PR China; Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Institute of Environment and Ecology, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, PR China
Wen-Long Wang: Shenzhen Key Laboratory of Ecological Remediation and Carbon Sequestration, Environmental Protection Key Laboratory of Microorganism Application and Risk Control, Institute of Environment and Ecology, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, PR China; Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Institute of Environment and Ecology, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, PR China
De-Xiu Wu: Shenzhen Key Laboratory of Ecological Remediation and Carbon Sequestration, Environmental Protection Key Laboratory of Microorganism Application and Risk Control, Institute of Environment and Ecology, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, PR China; Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Institute of Environment and Ecology, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, PR China
Shao-Yu Wang: Shenzhen Key Laboratory of Ecological Remediation and Carbon Sequestration, Environmental Protection Key Laboratory of Microorganism Application and Risk Control, Institute of Environment and Ecology, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, PR China; Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Institute of Environment and Ecology, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, PR China
Xiao Xiao: Shenzhen Key Laboratory of Ecological Remediation and Carbon Sequestration, Environmental Protection Key Laboratory of Microorganism Application and Risk Control, Institute of Environment and Ecology, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, PR China; Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Institute of Environment and Ecology, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, PR China
He-Qing Zhang: Cscec Scimee Science & Technical Company Limited, Chengdu 610041, PR China
Min-Yong Lee: National Institute of Environment Research, Ministry of Environment, Incheon 22689, Republic of Korea
Qian-Yuan Wu: Shenzhen Key Laboratory of Ecological Remediation and Carbon Sequestration, Environmental Protection Key Laboratory of Microorganism Application and Risk Control, Institute of Environment and Ecology, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, PR China; Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Institute of Environment and Ecology, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, PR China; Corresponding author at: Institute of Environment and Ecology, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, PR China.

Journal volume & issue: Vol. 182
p. 108314

Abstract

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Vacuum ultraviolet (VUV, 185 + 254 nm) irradiation performs well for oxidation of model pollutants. However, oxidation of pollutants does not necessarily lead to a reduction in toxicity. Currently, a comprehensive understanding of the effect of VUV irradiation on the toxicity of real wastewater is still lacking. In this study, the influence of VUV irradiation on the toxicity of secondary effluents to Chinese hamster ovary (CHO) cells was investigated. The induction units of endogenous reactive oxygen species (ROS) and 8-hydroxyguanosine (8-OHdG) in cells continuously decreased with prolonged irradiation time. After 36 min of irradiation, the cytotoxicity and the genotoxicity of the secondary effluents were reduced by 57%–63% and 56%–61%, respectively. The UV (254 nm), •OH, and other substances generated during the VUV irradiation directly drive toxicity changes of wastewater. The contribution of •OH generated during VUV irradiation to the reductions in cytotoxicity and genotoxicity of the secondary effluents reached 72%–78% and 77%–84%, respectively. Hydroxyl radicals generated during VUV irradiation played an important role in the detoxification. The relative signal intensity of dissolved organic carbon (DOC) > 500 Da was partially removed, whereas that of DOC 500 Da in the samples was much lower than that of DOC < 500 Da, the removal of total DOC was only 15.8%-20.0% after 36 min of irradiation. The UV254 values and the fluorescence intensity values for different molecular weights (MWs) were all reduced effectively by VUV irradiation. Electron-rich organic compounds of all MWs were all sensitive to VUV irradiation. There were mono-linear relationships between changes in chemical indexes and changes in cytotoxicity or genotoxicity. The total fluorescence intensity (Ex: 220–420 nm, Em: 280–560 nm) was identified as the best indicator of the reduction in toxicity.

Published in Environment International

ISSN: 0160-4120 (Print)
Publisher: Elsevier
Country of publisher: United Kingdom
LCC subjects: Geography. Anthropology. Recreation: Environmental sciences
Website: https://www.journals.elsevier.com/environment-international

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