Biwei Yang, Dong Ren, Peng Zhang, Yifan Guo, Gan Zhang, Alex Tat-Shing Chow, Zongwei Cai, Penghui Du* and Junjian Wang*,
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引用次数: 0
Abstract
Increasingly frequent wildfires tend to raise the levels of pyrogenic dissolved organic matter (DOM) and affect the photodegradation of organic pollutants in waterbodies within fire-prone watersheds. However, it remains unclear whether heating temperature and oxygen availability modify the DOM impact on the photodegradation of pollutants, such as sulfamethoxazole, a frequently detected antibiotic of significant concern. Here, we investigated the effects of DOM from nonheated soil and hypoxically and aerobically heated soils (250 or 400 °C) on sulfamethoxazole photodegradation and quantified the influence percentages of multiple pathways, including light screening, photosensitization, and reverse-back reduction. All DOMs inhibited sulfamethoxazole photodegradation, with lower inhibition seen for hypoxically heated soil DOMs than others. Additionally, 400 °C-heated soil DOMs exhibited more pronounced photosensitizing and reverse-back reduction pathways than 250 °C-heated soil DOMs. The relative abundances of condensed aromatics and oxygen-rich aromatics, which were higher in DOM from aerobically heated soil than from soil heated hypoxically, were significantly correlated with the influence percentages of photosensitization and the reverse-back reduction pathways. Our findings underscore the importance of wildfire prevention in mitigating the impact of pyrogenic DOM (particularly from aerobic heating) on pollutant retention by inhibiting photodegradation.
日益频繁的野火往往会提高热源溶解有机物(DOM)的水平,并影响火灾易发流域内水体中有机污染物的光降解。然而,加热温度和氧气供应是否会改变溶解有机物对污染物光降解的影响(如磺胺甲噁唑,一种经常检测到的引起重大关注的抗生素),目前仍不清楚。在此,我们研究了非加热土壤、低氧和有氧加热土壤(250 或 400 °C)中的 DOM 对磺胺甲噁唑光降解的影响,并量化了多种途径(包括光筛选、光敏化和反向还原)的影响百分比。所有 DOM 都能抑制磺胺甲噁唑的光降解,其中低氧加热土壤 DOM 的抑制作用低于其他 DOM。此外,与 250 °C 加热的土壤 DOM 相比,400 °C 加热的土壤 DOM 表现出更明显的光敏化和反向还原途径。有氧加热土壤 DOM 中的缩合芳烃和富氧芳烃的相对丰度高于低氧加热土壤 DOM,这与光敏化和反向还原途径的影响百分比显著相关。我们的研究结果强调了预防野火对通过抑制光降解来减轻热源 DOM(尤其是有氧加热产生的 DOM)对污染物滞留的影响的重要性。