第一作者:Lin Liang, Weiliang Pan
通讯作者:Xuan Guo
通讯单位:北京市农林科学院植物营养与资源环境研究所
DOI:10.1016/j.jhazmat.2024.136555
微塑料(MPs)和抗生素的累积对环境构成了协同威胁。本研究通过元基因组学分析,系统研究了环境水平(μg/L)的MPs(90-110 µm)和纳米塑料(NPs,700 nm)对处理土霉素污染废水的人工湿地(CWs)的影响。聚苯乙烯(PS)多孔塑料明显阻碍了氮、磷和土霉素的去除,尤其是在高浓度(1000 μg/L)时,去除率分别为 73.34 %、59.59 % 和 99.34 %。其中,与 CK 相比,NH4+-N 的去除率下降最多,为 15.26%。化武中的抗生素耐药基因(ARGs)拷贝数/16S rRNA 在 0.26 至 0.42 之间,是河流中抗生素耐药基因拷贝数的 1.5 至 2.5 倍。多药耐药基因(mdtB、acrB、mexF、mdtC 和 mexT)和四环素耐药基因(txtA、tetG 和 tetP)的相对丰度在 MPs 暴露下明显增加,分别为 0.06 至 0.14 和 0.01 至 0.08 个拷贝/16S rRNA。冗余和网络分析强调了污染物减少、ARG 丰度和微生物群落之间的密切联系。偏最小二乘法路径模型显示,与 NPs 相比,MPs 对污染物去除(系数 = 0.8194)、微生物群落(系数 = 0.3358)和 ARGs 传播(系数 = 0.6566)的影响更为深远。MPs 的浓度对污染物的去除和 ARGs 的增殖有明显影响,尺寸较大的 MPs 会扩大 ARGs 的传播。这项研究强调了 MPs 对以 CW 为媒介的废水处理和 ARGs 积累的影响,为开发适用于多污染物情况的生态废水处理策略提供了宝贵的见解。这些见解对于制定可持续的解决方案以解决 MPs 对生态系统的不利影响至关重要。
Fig. 1. Concentrations and average removal efficiencies of COD (a), NH4+-N (b), TP (c), and OTC (d) in influent and effluent water at different CWs during the experimental operation period. CK, NPL, NPH, MPL, and MPH represent control, 10 μg/L NPs-treated, 1000 μg/L NPs-treated, 10 μg/L MPs-treated, and 1000 μg/L MPs-treated groups, respectively. Within 95 % confidence, parameters with identical superscripts exhibit non-significant average value disparities.
Fig. 2. Accumulation of plastic particles by M. aquaticum under MPs/NPs treatment. (a) Confocal laser scanning microscopy (CLSM) of M. aquaticum roots, stems and leaves under NPH and MPH treatments; (b) NPs accumulation in M. aquaticum. CK, NPL, NPH, MPL, and MPH represent control, 10 μg/L NPs-treated, 1000 μg/L NPs-treated, 10 μg/L MPs-treated, and 1000 μg/L MPs-treated groups, respectively.
Fig. 3. (a) Chao1, (b) Shannon, (c) and Simpson α-diversity indicators and (d) principal component analysis (PCA) of microbial community structure among different treatments. CK, NPL, NPH, MPL, and MPH represent control, 10 μg/L NPs-treated, 1000 μg/L NPs-treated, 10 μg/L MPs-treated, and 1000 μg/L MPs-treated groups, respectively. Wilcoxon Rank Sum Test, and * means there is significant difference between the data (p < 0.05).
Fig. 4. (a) Microbial community relative abundances at the phylum level across all samples and (b) microbial community heatmap of CWs at genus level. The relative abundance data were calculated by taking Log10 of the initial data. CK, NPL, NPH, MPL, and MPH represent control, 10 μg/L NPs-treated, 1000 μg/L NPs-treated, 10 μg/L MPs-treated, and 1000 μg/L MPs-treated groups, respectively.
Fig. 5. Antibiotic resistance genes (ARGs) identification in the CWs. (a) Relative abundance of ARGs; (b) ARG-type principal component analysis (PCA) for all samples; (c) heatmap of ARGs type; (d) and comparison of previous ARGs with higher relative abundance. ARG counts were normalised based on 16S rRNA genes. ARGs were classified in terms of antibiotic category and resistance pattern. CK, NPL, NPH, MPL, and MPH represent control, 10 μg/L NPs-treated, 1000 μg/L NPs-treated, 10 μg/L MPs-treated, and 1000 μg/L MPs-treated groups, respectively. Wilcoxon Rank Sum Test, and * means there is significant difference between the data (p < 0.05).
Fig. 6. Relative abundance of the predominant subtypes of (a) tetracycline and (b) multidrug ARGs. CK, NPL, NPH, MPL, and MPH represent control, 10 μg/L NPs-treated, 1000 μg/L NPs-treated, 10 μg/L MPs-treated, and 1000 μg/L MPs-treated groups, respectively. Wilcoxon Rank Sum Test, and * means there is significant difference between the data (p < 0.05).
在化武中加入 MPs/NPs 会影响污染物去除率、微生物群落组成和 ARGs 丰度。具体而言,添加 PS 会降低对氮、磷和 OTC 的去除率,在 MPs 浓度较高(1000 μg/L)时效果更为明显。高浓度(1000 微克/升)和大粒径(90-110 微米)对 α 多样性和微生物群落结构的影响最大。值得注意的是,接触 NPs 会降低 ARGs 的丰度,而添加 MPs 则会使其富集。总之,这些发现强调了 MPs/NPs 与化武性能以及微生物群落动态之间的密切联系。这项研究为了解 MPs/NPs 对使用化武处理抗生素污染水的影响提供了宝贵的见解。今后的研究应进一步探讨 MPs/NPs 在化武中复杂的浓度和规模效应以及植物的反应。
Lin Liang, Weiliang Pan, Merui Mu, Lin Zhang, Xiangyu Yang, Ruina Zhang, Lianfeng Du, Xuan Guo, Effect of microplastics concentration and size on pollutants removal and antibiotic resistance genes (ARGs) generation in constructed wetlands: A metagenomics insight, Journal of Hazardous Materials, 2025, https://doi.org/10.1016/j.jhazmat.2024.136555
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