Institute of Organic Contaminant Control and Soil Remediation, College of Resource and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, PR China.
Soils Department, Faculty of Agriculture, Mansoura University, 35516 Mansoura, Egypt.
J Hazard Mater. 2022 Aug 5;435:129034. doi: 10.1016/j.jhazmat.2022.129034. Epub 2022 Apr 29.
High concentrations of Polycyclic Aromatic Hydrocarbons (PAHs) in the soils cause significant threats to human health. Since nitrogen plays a crucial role in controlling microbial composition and functions in terrestrial ecosystems, bio-stimulation based on nitrogen has been used in PAHs contaminated environments remediation. Recent studies show that microbial community composition and organic pollutants dissipation correlate with nitrogen addition. Here, we investigated the effect of nitrogen addition on the abundance of microbial community, degrading genes, and their relationship to PAHs dissipation. After a 32-day experiment, PAHs residues in nitrogen treatment soil were reduced by 23.23%-34.21%. The application of 80 mg·kg nitrate and ammonium nitrogen resulted in higher PAHs removal efficiency, and the dissipation rate of PAHs was 59.61% and 62.09%, respectively. Nitrogen application could improve the abundance and the diversity of soil microbial community. Degrading genes involved in PAH detoxification were enhanced after nitrogen addition, particularly those encoding ring-hydroxylating and catechol dioxygenases such as nahAc and nidA, thus, accelerating PAH dissipation in the soil. The results will facilitate the development of beneficial microbiome-based remediation strategies and improve agricultural production safety in PAHs-contaminated soils.
土壤中高浓度的多环芳烃（PAHs）对人类健康造成重大威胁。由于氮在控制陆地生态系统中微生物组成和功能方面起着至关重要的作用，因此基于氮的生物刺激已被用于修复受 PAHs 污染的环境。最近的研究表明，微生物群落组成和有机污染物的降解与氮的添加有关。在这里，我们研究了氮添加对微生物群落丰度、降解基因及其与 PAHs 降解关系的影响。经过 32 天的实验，氮处理土壤中的 PAHs 残留减少了 23.23%-34.21%。施加 80mg·kg 的硝酸盐和铵态氮会导致更高的 PAHs 去除效率，PAHs 的降解率分别为 59.61%和 62.09%。氮的施加可以提高土壤微生物群落的丰度和多样性。氮添加后，参与 PAH 解毒的降解基因得到增强，特别是那些编码苯环羟基化和儿茶酚双加氧酶的基因，如 nahAc 和 nidA，从而加速了土壤中 PAH 的降解。这些结果将有助于开发基于有益微生物组的修复策略，并提高受 PAHs 污染土壤中的农业生产安全性。
