Nitrogen addition is commonly used to remediate total petroleum hydrocarbons (TPH) in petroleum-contaminated soils. However, acceptable exogenous nitrogen dosages and their utilization efficiency for the degradation of hydrocarbons in oil-polluted soils are not well understood. This study compared the hydrocarbon bioremediation capacity by applying different doses of NHCl as a stimulant in soils contaminated with TPH at 8553 and 17090 mg/kg. The results showed acceptable exogenous nitrogen levels ranging from 60 to 360 mg N/kg soil, and the optimal nitrogen dosage for TPH remediation was 136 mg N/kg in soils with different TPH concentrations. The nitrogen availability efficiency (NAE) and nitrogen polarization factor availability (NPFA) in the 136 mg N/kg addition treatments were 6.69 and 20.47 mg/mg in 8533 mg/kg TPH-polluted soil, and 6.03 and 31.11 mg/mg in 17090 mg/kg TPH-polluted soil, respectively. Metagenomic analysis revealed that the application of 136 mg/kg nitrogen facilitated ammonia oxidation and nitrite reduction to nitric oxide, and induced soil microorganisms to undergo regulatory or adaptive changes in energy supply and metabolic state, which could aid in restoring the ecological functions of petroleum-contaminated soils. These findings underscore that 136 mg/kg of nitrogen dosage application is optimal for remediation of petroleum-contaminated soils irrespective of the TPH concentrations. This exogenous nitrogen application dosage for TPH remediation aligns with the nitrogen requirements for crop growth in agriculture.

中文翻译：

---

石油污染黄土生物修复过程中的氮利用效率评估：宏基因组分析的见解


添加氮气通常用于修复石油污染土壤中的总石油烃 (TPH)。然而，可接受的外源氮剂量及其对石油污染土壤中碳氢化合物降解的利用效率尚不清楚。本研究比较了在 TPH 污染土壤中应用不同剂量的 NH4Cl 作为刺激剂的碳氢化合物生物修复能力，浓度分别为 8553 和 17090 mg/kg。结果表明，可接受的外源氮水平范围为 60 至 360 mg N/kg 土壤，不同 TPH 浓度土壤中 TPH 修复的最佳施氮剂量为 136 mg N/kg。 8533 mg/kg TPH 污染土壤中 136 mg N/kg 添加处理的氮有效性效率（NAE）和氮极化因子有效性（NPFA）分别为 6.69 和 20.47 mg/mg，17090 污染土壤中氮有效性效率（NAE）和氮极化因子有效性（NPFA）分别为 6.03 和 31.11 mg/mg。分别为 mg/kg TPH 污染土壤。宏基因组分析表明，施用136 mg/kg氮肥促进氨氧化和亚硝酸盐还原为一氧化氮，并诱导土壤微生物在能量供应和代谢状态方面发生调节或适应性变化，这有助于恢复石油和天然气的生态功能。被污染的土壤。这些发现强调，无论 TPH 浓度如何，136 mg/kg 的氮肥剂量对于修复受石油污染的土壤来说是最佳的。这种用于 TPH 修复的外源氮施用剂量与农业作物生长的氮需求一致。