Li Danyang, Ma Xiaoyan Y, Zhang Shiying, Wang Yongkun K, Han Yingnan, Chen Rong, Wang Xiaochang C, Ngo Huu Hao
Key Lab of Environmental Engineering (Shaanxi province), School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China.
Key Lab of Environmental Engineering (Shaanxi province), School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Key Laboratory of Northwest Water Resource, Environment and Ecology (Ministry of Education), Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China.
Water Res. 2023 Jun 30;238:120002. doi: 10.1016/j.watres.2023.120002. Epub 2023 Apr 25.
Natural sunlight can reduce the chemicals of emerging concern (CECs) and biological effects from the discharged domestic wastewater. But the aquatic photolysis and biotoxic variations of specific CECs detected in secondary effluent (SE) were not clear. In this study, 29 CECs were detected in the SE, and 13 medium- and high-risk CECs were identified as target chemicals based on their ecological risk assessment. To comprehensively explore the photolysis properties of the identified target chemicals, the direct and self-sensitized photodegradation of the target chemicals, even the indirect photodegradation in the mixture, were investigated and compared with these photodegradation in the SE. Of the 13 target chemicals, only five chemicals (including dichlorvos (DDVP), mefenamic acid (MEF), diphenhydramine hydrochloride (DPH), chlorpyrifos (CPF), and imidacloprid (IMI)) underwent direct and self-sensitized photodegradation processes. The removal of DDVP, MEF, and DPH was attributed to self-sensitized photodegradation, which was mainly mediated by •OH; CPF and IMI primarily relied on direct photodegradation. Synergistic and/or antagonistic actions that occurred in the mixture improved/decreased the rate constants of five photodegradable target chemicals. Meanwhile, the biotoxicities (acute toxicity and genotoxicity) of the target chemicals (including individual chemicals and the mixture) were significantly reduced, which can explain the reduction of biotoxicities from SE. For the two refractory high-risk chemicals, atrazine (ATZ) and carbendazim (MBC), algae-derived intracellular dissolved organic matter (IOM) on ATZ, and IOM and extracellular dissolved organic matter (EOM) on MBC had slightly promotion for their photodegradation; while peroxysulfate, and peroxymonosulfate served as sensitizers were activated by natural sunlight and effectively improved their photodegradation rate, and then reduced their biotoxicities. These findings will promote the development of CECs treatment technologies based on sunlight irradiation.
自然阳光可以减少新出现的关注化学物质（CECs）以及生活污水排放带来的生物效应。但是，二级出水（SE）中特定CECs的水生光解和生物毒性变化尚不清楚。在本研究中，在SE中检测到29种CECs，并根据其生态风险评估确定了13种中高风险CECs作为目标化学物质。为了全面探究所确定目标化学物质的光解特性，研究了目标化学物质的直接光降解、自敏化光降解，甚至混合物中的间接光降解，并与SE中的这些光降解进行了比较。在这13种目标化学物质中，只有五种化学物质（包括敌敌畏（DDVP）、甲芬那酸（MEF）、盐酸苯海拉明（DPH）、毒死蜱（CPF）和吡虫啉（IMI））经历了直接光降解和自敏化光降解过程。DDVP、MEF和DPH的去除归因于自敏化光降解，其主要由•OH介导；CPF和IMI主要依赖直接光降解。混合物中发生的协同和/或拮抗作用提高/降低了五种可光降解目标化学物质的速率常数。同时，目标化学物质（包括单一化学物质和混合物）的生物毒性（急性毒性和遗传毒性）显著降低，这可以解释SE生物毒性的降低。对于两种难降解的高风险化学物质，阿特拉津（ATZ）和多菌灵（MBC），藻类衍生的细胞内溶解有机物（IOM）对ATZ，以及IOM和细胞外溶解有机物（EOM）对MBC的光降解有轻微促进作用；而过硫酸盐和过一硫酸盐作为敏化剂被自然阳光激活，有效提高了它们的光降解速率，进而降低了它们的生物毒性。这些发现将推动基于阳光照射的CECs处理技术的发展。
