Ouyang Shaohu, Zhou Qixing, Yuan Peng, Gao Yang, Sun Jing, Zou Wei, Hu Xiangang
Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education)/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China.
Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education)/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China.
Water Res. 2023 Apr 1;232:119678. doi: 10.1016/j.watres.2023.119678. Epub 2023 Jan 29.
Hematite (the most abundant iron oxide polymorph) is widely detected in the water environment and has attracted considerable attention. Natural nanocolloids (Ncs) exist ubiquitously in surface waters and play critical roles in biogeochemical processes. However, the influences of Ncs on the fate and phytotoxicity of hematite remain unknown. In this study, the infrared absorption spectra coupled with two-dimensional correlation spectroscopy analysis reveal that the specific binding interactions between Ncs and hematite primarily occur via hydrophilic effects and π-π interactions with an increase in the Ncs contact time. Moreover, binding with Ncs slightly promoted the aggregation rates of hematite particles in the BG-11 medium. Interestingly, Ncs remarkably mitigate the phytotoxicity (e.g., growth inhibition, oxidative stress, and mitochondrial toxicity) of nanosized and submicrosized hematite particles to Chlorella vulgaris after a 96 h exposure. The integrating metabolomic and transcriptomic analysis reveals that the regulated urea cycle, amino acids, and fatty acid-related metabolites (e.g., urea, serine, glutamate, and hexadecenoic acid) and genes (e.g., ACY1, CysC, and GLA) contribute to persistent phytotoxicity. This study provides new insights into the roles and mechanisms of natural Ncs in regulating the environmental risk of iron oxide minerals in aqueous media.
赤铁矿（最丰富的氧化铁多晶型物）在水环境中被广泛检测到，并引起了相当大的关注。天然纳米胶体（Ncs）普遍存在于地表水中，并在生物地球化学过程中发挥关键作用。然而，Ncs对赤铁矿的归宿和植物毒性的影响仍然未知。在本研究中，红外吸收光谱结合二维相关光谱分析表明，随着Ncs接触时间的增加，Ncs与赤铁矿之间的特定结合相互作用主要通过亲水作用和π-π相互作用发生。此外，与Ncs结合略微促进了BG-11培养基中赤铁矿颗粒的聚集速率。有趣的是，在暴露96小时后，Ncs显著减轻了纳米级和亚微米级赤铁矿颗粒对普通小球藻的植物毒性（例如生长抑制、氧化应激和线粒体毒性）。综合代谢组学和转录组学分析表明，受调控的尿素循环、氨基酸和脂肪酸相关代谢物（例如尿素、丝氨酸、谷氨酸和十六碳烯酸）以及基因（例如ACY1、CysC和GLA）导致持续的植物毒性。本研究为天然Ncs在调节水介质中氧化铁矿物的环境风险方面的作用和机制提供了新的见解。
