College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, China.
Institute of Nuclear Agricultural Sciences, Key Laboratory of Nuclear Agricultural Sciences of Ministry of Agriculture and Zhejiang Province, Zhejiang University, Hangzhou 310058, China.
Sci Total Environ. 2024 Oct 10;946:173858. doi: 10.1016/j.scitotenv.2024.173858. Epub 2024 Jun 12.
Increasing use and release of graphene nanomaterials and pharmaceutical and personal care products (PPCPs) in soil environment have polluted the environment and posed high ecological risks. However, little is understood about the interactive effects and mechanism of graphene on the behaviors of PPCPs in soil. In the present study, the effects of reduced graphene oxide nanomaterials (RGO) on the fate of triclosan in two typical soils (S1: silty loam; S2: silty clay loam) were investigated with C-triclosan, high-resolution mass spectrometry, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), density functional theory (DFT) calculations, and microbial community structure analysis. The results showed that RGO prolonged the half-life of triclosan by 23.6-51.3 %, but delayed the formation of transformed products such as methyl triclosan and dechlorinated dimer of triclosan in the two typical soils. Mineralization of triclosan to CO was inhibited by 48.2-79.3 % in 500 mg kg RGO in comparison with that in the control, whereas the bound residue was 54.2-56.4 % greater than the control. RGO also reduced the relative abundances of triclosan-degrading bacteria (Pseudomonas and Sphingomonas) in soils. Compared to silty loam, RGO more effectively inhibited triclosan degradation in silty clay loam. Furthermore, the DFT calculations suggested a strong association of the adsorption of triclosan on RGO with the van der Waals forces and π-π interactions. These results revealed that RGO inhibited the transformation of C-triclosan in soil through strong adsorption and triclosan-degrading bacteria inhibition in soils. Therefore, the presence of RGO may potentially enhance persistence of triclosan in soil. Overall, our study provides valuable insights into the risk assessment of triclosan in the presence of GNs in soil environment.
在土壤环境中，石墨烯纳米材料和药品及个人护理产品（PPCPs）的使用和释放不断增加，对环境造成了污染，并带来了高生态风险。然而，人们对石墨烯对土壤中 PPCPs 行为的相互作用和机制知之甚少。在本研究中，使用 C-三氯生、高分辨率质谱、扫描电子显微镜（SEM）、X 射线光电子能谱（XPS）、密度泛函理论（DFT）计算和微生物群落结构分析，研究了还原氧化石墨烯纳米材料（RGO）对两种典型土壤（S1：粉质壤土；S2：粉质黏土）中三氯生命运的影响。结果表明，RGO 将三氯生的半衰期延长了 23.6-51.3%，但延迟了在两种典型土壤中形成甲基三氯生和三氯生脱氯二聚体等转化产物。与对照相比，在 500mgkg RGO 下，三氯生向 CO 的矿化抑制了 48.2-79.3%，而结合残留量比对照增加了 54.2-56.4%。RGO 还降低了土壤中三氯生降解菌（假单胞菌和鞘氨醇单胞菌）的相对丰度。与粉质壤土相比，RGO 更有效地抑制了粉质黏土中三氯生的降解。此外，DFT 计算表明，三氯生在 RGO 上的吸附与范德华力和π-π相互作用有很强的关联。这些结果表明，RGO 通过在土壤中强烈吸附三氯生和抑制三氯生降解菌，抑制了土壤中 C-三氯生的转化。因此，RGO 的存在可能会潜在地增加土壤中三氯生的持久性。总的来说，我们的研究为评估土壤环境中 GNs 存在下三氯生的风险提供了有价值的见解。
