微塑料对环境介质中氮循环的影响研究进展

卢萍; 闫振华; 陆光华

doi:10.13198/j.issn.1001-6929.2021.08.08

微塑料对环境介质中氮循环的影响研究进展

doi: 10.13198/j.issn.1001-6929.2021.08.08

河海大学环境学院, 浅水湖泊综合治理与资源开发教育部重点实验室, 江苏南京 210098

基金项目:

国家自然科学基金项目 51979080

中央高校基本科研业务费 B200202113

详细信息

作者简介:
卢萍(1997-), 男, 江苏高邮人, luping@hhu.edu.cn

通讯作者:
闫振华(1987-), 男, 河南辉县人, 副教授, 博士, 主要从事新污染物环境行为研究, hwahuer@hhu.edu.cn

中图分类号: X131
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出版历程
- 收稿日期: 2021-05-12
- 修回日期: 2021-07-27

Influence of Microplastics on Nitrogen Cycle in Different Environments

Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China

Funds:

National Natural Science Foundation of China 51979080

Fundamental Research Funds for the Central Universities, China B200202113

摘要

摘要: 微塑料作为一种新污染物，在全球范围内引发了广泛关注.微塑料在威胁生物体健康的同时，也会通过定殖微生物等途径影响氮素正常的循环过程，但相关研究仍相对匮乏.本文在简述当前微塑料污染现状的基础上，介绍了微塑料对污泥、水、沉积物和土壤4种环境介质中氮循环的影响研究进展，并重点分析了微塑料作用下不同环境介质中氮转化过程的响应及作用机制.结果表明：当前微塑料影响氮循环的研究主要集中于污泥和土壤，对水环境和沉积物中的研究相对较少；环境介质和微塑料的聚合物类型、浓度、粒径等因素都会导致微塑料对氮循环的影响产生明显差异.进一步分析发现，微塑料主要通过影响氮转化相关的微生物、酶活性和功能基因以及改变氧通量等来影响硝化和反硝化等过程，其中，微生物受塑料添加剂释放的影响较大，微塑料自身也可能作为有机底物促进相关功能菌的生长；硝化和反硝化过程中关键酶及功能基因也会对微塑料的影响产生响应，进而影响氮循环过程.此外，微塑料能够通过改变沉积物的孔隙度增加氧通量，增强硝化作用.在后续研究中应重点关注微塑料参与氮循环的环境驱动机制，阐述其在潜流带等地球关键带中的作用路径，为全面评估微塑料对生态环境健康的影响提供支持.
- 微塑料 /
- 氮转化 /
- 微生物 /
- 环境介质
Abstract: Microplastic, as an emerging pollutant, has received increasing concerns worldwide. In addition to threatening the health of organisms, microplastics may also affect the nitrogen cycles by altering the colonized biofilms. However, the relevant research is relatively scarce. Based on the microplastic pollution status in different environments, the impact of microplastics on nitrogen transformation in different environmental media (e.g., sludge, water, sediment, and soil) was introduced. Then, the response and transformation mechanism were analyzed in detail. It is found that previous studies mainly focused on the influence impact of microplastics on the nitrogen cycle in sludge and soil, while few of them were conducted in water and sediment. Many influencing factors, including environmental media, polymers, concentration, and size of microplastics, can significantly change the impact of microplastics on the nitrogen cycle. Generally, microplastics can affect the processes of nitrification and denitrification in the environments by affecting the microbial community, enzyme activities, and functional genes related to nitrogen transformation, as well as changing the oxygen flux. The microbial community was mainly affected by the additives released from the microplastics. In addition, microplastics may also promote the growth of the related microbial communities as an organic substrate. Furthermore, microplastics can increase oxygen flux by changing the porosity of the sediment, thereby enhancing nitrification. In the future, more attention should be paid to the impact of microplastics on the nitrogen cycle under different environmental factors or in the critical zones of the earth, such as the hyporheic zone. These results are useful to comprehensively assess the impact of microplastics on ecological and environmental health.
- microplastic /
- nitrogen transformation /
- microorganism /
- environmental media

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图 1 微塑料影响氮转化的主要方式

Figure 1. Potential influence pathways of microplastics on nitrogen transformation

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表 1 微塑料对不同环境介质中氮转化的影响

Table 1. Effects of microplastics on nitrogen transformation in different environments

环境介质	微塑料类型	粒径	浓度	影响	数据来源
好氧颗粒污泥	PVC	—	0、0.5、5、50 mg/L	PVC微塑料降低反硝化细菌的含量，抑制氮的去除	文献[29]
活性污泥	PVC、PP、PE、PS、PES	—	0、1 000、5 000、10 000 particles/L	微塑料轻微抑制活性污泥的硝化作用，促进反硝化作用；PVC微塑料在硝化过程中轻微抑制N₂O的排放，在反硝化过程中促进N₂O的排放	文献[30]
好氧颗粒污泥	PES	0.25 mm	0、0.1、0.2、0.5 g/L	PES微塑料导致亚硝酸盐氧化酶活性，细胞色素c亚基Ⅱ和细胞色素b亚基Ⅰ的丰度降低，硝酸还原酶丰度增加，亚硝酸盐氮积累，影响氮代谢过程	文献[31]
反硝化污泥	PS、PA	PS，60 nm；PA，37~74 μm	250 μg/L	PS、PA微塑料抑制好氧反硝化菌群的脱氮性能，产生一定量亚硝酸盐氮的积累；微生物群落多样性提高，napA和nirS基因丰度降低	文献[32]
淡水	PP	5mm×5 mm×0.3 mm正方形薄片	25 items/L	微塑料生物膜促进氨氮和亚硝酸盐的氧化和反硝化；成熟生物膜的解体将氮重新释放到水中	文献[28]
淡水	PS	100 nm~9 μm	5~100 mg/L	高浓度的PS微珠(100 nm，100 mg/L)显著降低叶绿素a的含量以及β-葡萄糖苷酶和亮氨酸-氨基肽酶的功能酶活性，不利于淡水生物膜的氮循环	文献[25]
沉积物	PE、PVC、PUF、PLA	53~300 μm	0.5%	PUF和PLA微塑料可促进硝化和反硝化作用，PVC微塑料抑制这两个过程；微塑料可作为微生物群落的有机碳底物，显著影响沉积物中的氮循环过程	文献[41]
沉积物	PE	37.1 μm	0、0.1%、1%	添加微塑料促进反硝化细菌和厌氧氨氧化菌的生长，提高总氮去除率；1% PE的微塑料对大型无脊椎动物介导的生物脱氮有不利影响	文献[42]
沉积物	PLA、HDPE、PVC	(235.7±14.8)μm、(102.6±10.3)μm、(130.6±12.9)μm	0.02%、0.2%、2%	高浓度微塑料影响底栖生物Arenicola marina的健康和生物活性及其介导的沉积物氮循环过程	文献[43]
沉积物	PET	—	0~0.5 g/kg	纤维微塑料浓度的增加会影响近海沉积物底栖生物的生态功能，进而影响氮的生物地球化学过程	文献[44]
土壤	PS	(32.6±11.9)nm	10、100、1 000 ng/g	PS微塑料降低关键氮循环酶亮氨酸-氨基肽酶活性，土壤中氮的潜在利用潜力受到影响	文献[50]
土壤	LDPE	80~450 μm	0、0.1%、0.5%、1%、3%、6%、18%	LDPE微塑料降低了土壤氨氧化细菌和亚硝酸盐还原酶的丰度，对氨氧化古菌、亚硝酸盐还原酶和氧化亚氮还原酶的功能基因影响较小；对微生物群落具有明显的影响，可能影响全球氮循环	文献[51]
土壤	PE	2 mm×2 mm×0.01 mm	200 items/(100 g)	PE微塑料影响有机氮的水解，PE存在下更高的脲酶活性表明其对氮循环产生作用	文献[52]
土壤	塑料薄膜	—	—	减少土壤无机氮含量，降低与氮转化相关的基因表达和酶活性；与固氮相关的功能基因(nifH)、与N₂O还原有关的基因(nosZ)以及反硝化有关功能基因(nirS)的丰度升高，反硝化基因(nirK)降低	文献[53]
土壤	PLA	20~50 μm	2%	PLA微塑料改性的土壤氨转化速率更快	文献[55]

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