College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China.
College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China; Key Laboratory of Low-carbon Green Agriculture in Northwestern China, Ministry of Agriculture and Rural Affairs, China.
Sci Total Environ. 2022 Dec 20;853:158571. doi: 10.1016/j.scitotenv.2022.158571. Epub 2022 Sep 6.
Environmentally persistent free radicals (EPFRs) as intermediate products exist widely in the PAHs-contaminated soils, but toxicity assessment associated with EPFRs for terrestrial invertebrates remains unclear. Using the model organism Eisenia fetida, we compared the adverse effects among anthracene (ANT), anthraquinone (ANQ), and EPFRs induced by ANT transformation on clay surfaces. Our results showed that EPFRs-exposed earthworms experienced histopathological damage, which was more severe than ANT and ANQ-exposed earthworms. The source of EPFRs damage was associated with the obvious dysbiosis of reactive oxygen species in earthworms. Specifically, EPFRs trigged more severe antioxidant responses and oxidative damages (e.g., membrane lipid and DNA injury) in comparison with ANT and ANQ exposure, as evidenced by the values of integrated biomarker response (IBR) following the order of EPFRs (14.5) > ANT (12.8) > ANQ (10.9). Moreover, high-throughput sequencing found that EPFRs induced dramatic changes in the composition and structure of earthworm gut microbiota, which may involve immune and metabolism dysfunction, in turn aggravated EPFRs toxicity. Overall, the obtained information highlights the more severe injury of EPFRs to terrestrial organisms, deserving more attentions for the assessment of potential risks associated with radical intermediates in PAHs-contaminated soils.
环境持久性自由基（EPFRs）作为中间产物广泛存在于多环芳烃污染土壤中，但关于 EPFRs 对陆地无脊椎动物的毒性评估仍不清楚。本研究采用模式生物赤子爱胜蚓（Eisenia fetida），比较了多环芳烃污染物蒽（ANT）、蒽醌（ANQ）及其在粘土表面转化生成的 EPFRs 对蚯蚓的急性毒性。结果表明，EPFRs 暴露导致蚯蚓组织病理损伤，其严重程度高于 ANT 和 ANQ 暴露。EPFRs 损伤的根源与蚯蚓体内活性氧的明显失调有关。具体而言，与 ANT 和 ANQ 暴露相比，EPFRs 引发了更严重的抗氧化反应和氧化损伤（例如，膜脂和 DNA 损伤），这体现在整合生物标志物响应（IBR）值的顺序为 EPFRs（14.5）>ANT（12.8）>ANQ（10.9）。此外，高通量测序发现，EPFRs 诱导了蚯蚓肠道微生物群落组成和结构的剧烈变化，这可能涉及免疫和代谢功能障碍，从而加剧了 EPFRs 的毒性。总之，研究结果突出了 EPFRs 对陆地生物的更严重损伤，这为评估多环芳烃污染土壤中自由基中间体相关的潜在风险提供了更多的关注。
