The DeNitrification-DeComposition (DNDC) model has been widely used to simulate soil carbon and nitrogen cycling in open-field agroecosystems. However, its performance under greenhouse cultivation remains insufficiently evaluated. This study assessed the ability of the DNDC model to reproduce soil carbon and nitrogen dynamics in a greenhouse tomato system. Field observations and model simulations were further combined to examine the effects of elevated CO2 (eCO2) enrichment on soil carbon emission, soil nitrogen dynamics, tomato physiological responses, and yield under different fertilization regimes. Results showed that the DNDC model showed good performance in simulating temporal changes in soil organic carbon, ammonium nitrogen, and nitrate nitrogen under eCO2 fertilization, with model efficiency values exceeding 0.66. Under eCO2 combined with chemical fertilizer application, total soil carbon emission decreased to 3120.34 kg·ha−1, which was approximately 1.9 times lower than that in CK. Elevated CO2 also improved tomato physiological performance under the greenhouse conditions of this study, as reflected by increases in net photosynthetic rate, intercellular CO2 concentration, stomatal conductance, and transpiration rate. These responses were associated with enhanced plant carbon accumulation and ultimately contributed to increased tomato yield. These findings highlight the potential of DNDC for greenhouse carbon–nitrogen assessment and of eCO2-based fertilization management for improving tomato productivity.

This study focused on slightly to moderately PAH-contaminated farmland soils in freeze-thaw regions of Northeast China, aiming to fill the research gap in the in situ remediation mechanisms of PAHs under natural freeze-thaw conditions. A 12-month in situ experiment was conducted with four treatments-blank control (CK), biochar (BC), microbial agent (MA), and immobilized microorganisms (IM)-to verify that biochar-loaded IM alleviates temperature stress and sustains efficient PAH removal by regulating soil and microbial properties. PAH removal efficiency and soil chemical properties were monitored during both normal-temperature and freeze-thaw periods, and the soil bacterial community structure was analyzed at the end of the experiment. Results showed that IM achieved the optimal remediation performance with a total PAH removal rate of 72.53%, was least affected by temperature fluctuations, and maintained stable remediation during the freeze-thaw period. IM increased soil nutrient contents, with available potassium and nitrogen exerted positive effects on PAH degradation; it also enriched the functional genes K00626 and K00457 and comprehensively optimized the bacterial community. This study clarified the core remediation mechanism and provided scientific, technical, and theoretical support for related in situ remediation practices.

Afforestation with Pinus sylvestris var. mongolica in northern China is hindered by soil degradation. This study evaluated a ternary amendment combining sewage sludge (SS), cattle manure (CM), and maize straw (MS) to rehabilitate degraded sandy soils in the Horqin Sandy Land. Five treatments were tested: control (CK), SS (T1), SS + CM (T2), SS + MS (T3), and SS + CM + MS (T4). The ternary amendment (T4) achieved optimal outcomes: soil pH decreased from 8.02 to 7.79, organic carbon increased 2.5–fold, and total nitrogen (127%) and phosphorus (87.5%) were enhanced compared to CK. Pinus sylvestris exhibited a 65.6% greater basal diameter and 29.5% height increase under T4, while heavy metal concentrations (Cd: −54.6%, Cu: −35.1%, Pb: −12.2% and Zn: −27.6%) were reduced. These findings highlight a synergistic waste valorization strategy for dryland afforestation, balancing soil fertility improvement with ecological safety. Future studies should prioritize long-term microbial community dynamics and field-scale validation.

The content of PAHs in surface soils of northeastern China is high, which causes long-term soil pollution and potential harm to human health. Influenced by the temperature, the soil in the northeast region is characterized by a long-term freeze–thaw seasonal climate, which greatly affects the process of soil remediation work. Therefore, it is necessary to study the remediation strategies of PAHs in low-temperature soils. Our group discovered that the combination of cold-tolerant fungi and bacteria was effective in degrading soil PAHs. However, we are required to further explore the choice of immobilization vector. In this study, four different types of biochar (C300, C500, B300, B500) were prepared at 300 °C and 500 °C using corn cob and wheat straw of industrial and agricultural waste as precursors. We then used the cross-mixing of these four types of biochar as the carrier for Pseudomonas sp. S4 and Mortierella alpina J7, which are bacteria capable of degrading PAHs. We used the adsorption immobilization method to prepare the repair materials for PAHs degradation mixed bacteria. Through comparison, the low-temperature and high-temperature mixed biochar (C300 + B500) was selected as the carrier. The results showed that mixed biochar immobilized degrading bacteria are the most effective in degrading Phe and Pyr in soil and their degradation effect was related to the mixing ratio. After 30 days of remediation at 15 °C, the best remediation effect was add immobilized mixed fungicide agent, mix biochar 1:2 using 0.67

Polycyclic aromatic hydrocarbons (PAHs), widespread organic pollutants, significantly impact human health and environmental integrity. Recent approaches to ameliorate PAH-contaminated soils, particularly in cold environments, have been insufficient. This study investigates the use of immobilized low -temperature -resistant mixed microorganisms (LTRMM) for enhancing the degradation of PAHs in soils from coke plants and the Shenfu irrigation area. Our results demonstrate that treatment with immobilized mixed microorganisms (MC -HS) is more effective than treatments with free bacteria (H -S) and control (CK). Specifically, the degradation rates in the MC-HS1 treatment were 10.10 % -41.13 % higher than those in the coking plant soil treated with CK1 and HS1. Similarly, in the Shenfu irrigation area soil, MC-HS2 showed improvements of 6.00 % to 52.56 % over CK2 and H -S2. A kinetic model was used to analyze the enhanced degradation capabilities, revealing that the half-life of PAHs under the immobilized mixed microorganism treatment (T3) was significantly shorter compared to the free bacteria (T2) and control treatments (T1). These findings suggest that employing immobilized LTRMM could significantly improve the remediation efficiency of PAH-contaminated soils in cold climates.

为寻找适用于北方寒冷地区有机污染土壤的生物修复材料,从某炼油厂冻融土壤中筛选出一株以腐殖酸(HA)吸附态PAHs为碳源和能源且生长良好的耐低温真菌(命名为JDR7),经鉴定为高山被孢霉(Mortierella alpina),并研究了其对冻融土壤中HA吸附态PAHs的降解动态,用Michaelis-Menton和Monod动力学模型对结果进行拟合.结果表明:经42d,JDR7对冻融土壤中Pyr和BaP的降解率分别为68.13％和59.51％.加入HA后,42d的降解率分别提高13.8％和12.3％;降解初期加入HA可显著提高Pyr和BaP的降解速率,第一周降解速率分别提高29.69％和32.93％,后期促进降解效果减弱.该研究为北方寒冷地区土壤PAHs污染微生物修复提供新的修复材料.

为了从环境中筛选耐低温PAHs降解真菌,从某炼油厂冻融土壤中筛选出一株以腐殖酸(HA)吸附态PAHs为碳源和能源且生长良好的耐低温真菌(命名为JDR7),经鉴定为高山被孢霉(Mortierella alpina),并采用修复实验研究了其对冻融土壤中HA吸附态PAHs的降解性能.结果表明:JDR7 对冻融土壤中Phe和Pyr均具有降解能力,42d降解率分别为 80.70%和 68.13%;HA的添加,可提高降解率,42 d后JDR7 对冻融土壤中Phe和Pyr降解率分别提高 12.3%和 13.8%;若要在寒冷地区选择Mortierella alpina JDR7 作为固定化真菌,可添加HA提高其修复效果.本研究为北方寒冷地区土壤PAHs污染微生物修复提供新的菌株.

The work aimed to explore effects of polytetrafluoroethylene nanoplastics on joint inhibitions of ciprofloxacin and bivalent copper on the nitrogen removal in a sequencing batch reactor and its potential mechanisms. The addition of bivalent copper and/or ciprofloxacin reduced the ammonia nitrogen elimination rate with or without polytetrafluoroethylene nanoplastics. Adsorption kinetics and thermodynamics showed the binary bivalent copper and ciprofloxacin promoted their adsorptions by polytetrafluoroethylene nanoplastics. Polytetrafluoroethylene nanoplastics enhanced combined toxicities of ciprofloxacin and bivalent copper to sludge activities and microbial community involved into nitrification and denitrification due to the adsorption of ciprofloxacin and bivalent copper by polytetrafluoroethylene nanoplastics. With or without polytetrafluoroethylene nanoplastics, bivalent copper and/or ciprofloxacin caused more obvious level changes of protein than polysaccharide. This study provides novel insights for understanding the effect of combined heavy metals and antibiotics on the performance in a sequencing batch reactor with the nanoplastics stress.

The aim of the research was to assess the feasibility of adding modified loofah sponge to increase bioavailability and enhance the removal of phenanthrene (Phe) in soil environment. High temperature and pressure (0.125 MPa, 130 degrees C) could significantly increase the wrinkles, surface area of loofah sponge (142.35 m(2) g(-1)), and this modification improved Phe adsorption on the loofah sponge. Carbon content in the modified loofah sponge increased to 46.53%. After the modified loofah sponge was added to the Phecontaminated soils, the overall adsorption of Phe onto the mixture increased. However, due to the existence of competitive adsorption, the adsorption of Phe by soil decreased. The addition of modified loofah sponges in the soils significantly influenced the behavior and adsorption potential of Phe for different initial concentration in the soil. Compared with at pH 7, the migration of Phe from soil to modified loofah sponge increased at pH 6 or 8. The pseudo-second-order kinetic showed an excellent fitness with the experimental kinetic data in describing Phe dynamic adsorption on the modified loofah sponge. The possible mechanism of Phe retention on modified loofah sponge was chemical adsorption. These results from this study will improve knowledge on understanding the adsorption mechanism of Polycyclic aromatic hydrocarbons (PAHs) onto biomass materials in soil and provide a theoretical foundation for using modified loofah sponge as a green cost-effective sorbent to remediate PAHscontaminated soil. (c) 2021 Elsevier Ltd. All rights reserved.

There are large areas of contaminated soils with low- and medium-concentration of polycyclic aromatic hydrocarbons (PAHs) in the coldest regions of the earth, potentially threatening ecological safety and human health. Using maize cobs (MC) as the carrier, two cold-adaptive PAHs-degrading microorganisms, bacterial (Pseudomonas sp., SDR4) and fungal (Mortierella alpine, JDR7) strains were co-immobilized. The degradation characteristics of phenanthrene (Phe), pyrene (Pyr) and benzo[a]pyrene (BaP) in freeze-thawed soil by both co-immobilized and free microorganism were studied. The removal rate of Phe, Pyr and BaP using the co-immobilized fungal-bacterial consortium within 60 d was 59.2±3.7%, 46.6±3.3%, and 36.8±2.7%, respectively, which was obviously higher than that of free fungal-bacterial consortium in the same time. Ten percent (w/w) was the optimal amount of inoculum for PAH degradation in the co-immobilized fungal-bacterial consortium. Under low-temperature conditions, when the initial concentration of PAH was between 10-100 mg•kg−1, the immobilized cold-adaptive fungal-bacterial consortium displayed the desired degradation of PAHs. The scanning electronic microscope (SEM) observation and mass transmission showed that the microstructure of co-immobilized mixed system was beneficial to the growth of SDR4 and JDR7 at low temperature. These results imply that the cold-adaptive fungal-bacterial consortium, co-immobilized on MC, has the potential for application in remediating PAH contaminated soil under the freeze-thawing environment.

采用高效液相色谱法对沈阳市地表土壤中的多环芳烃(Polycyclic Aromatic Hydrocarbons,PAHs)进行了定量分析,研究了沈阳市地表土壤中PAHs在不同功能区的含量及分布特征.结果表明:从土壤PAHs总量来看,居民区最低,其次是商业区,交通干道、文教区和公园排在商业区之后,工业区的PAHs总量最多;从PAHs的空间差异来看,靠近工业区以及机动车车流量较大的地区PAHs含量较高,靠近文教区和居住区的地区PAHs含量较低;从PAHs种类来看,所有功能区样品中PAHs的组分分布状况较为一致,以四环PAHs含量最多,其次是五环PAHs和三环PAHs;参考美国EPA沉积物PAHs质量标准和治理标准,沈阳市内五区PAHs总量超过质量标准的功能区有工业区、交通干道(4个采样点,占比36.3％)、文教区(3个采样点,占比75％)和公园区(4个采样点,占比40％),超过治理标准的功能区有工业区,公园区(1个采样点,占比10％),文教区(1个采样点,25％).

以假单胞菌(Pseudomonas sp.SDR4,简称S4)、毛霉真菌(Mucormucedo sp.SDR1,简称S1)为研究对象,采用微生物固定化技术,研究了其对土壤多环芳烃的吸附和降解动力学,并探讨了固定化微生物对土壤多环芳烃的吸附机理及吸附降解关系.结果表明:试验60 d,改性丝瓜络(CK)、死体固定化S1(S1-D)、死体固定化S4(S4-D)、死体固定化S1与S4混合菌(S1+S4-D)对菲(Phe)的动态平衡吸附量分别为5.28、6.82、5.73、7.46μg,对芘(Pyr)的动态平衡吸附量分别为4.17、4.72、4.53、5.00μg,死体固定化微生物对Phe与Pyr的吸附过程均服从于准二级动力学;活体真菌S1、细菌S4、混合菌S1+S4对Phe的动态吸附量分别为2.32、2.01、2.76μg,对Pyr的动态吸附量分别为2.79、2.41、3.14μg,活体固定化微生物对土壤中Phe与Pyr的准一级动力学与准二级动力学拟合结果R2相差较小;S1、S4、S1+S4对Phe的降解率分别为54.34％、61.45％、64.23％,对Pyr的降解率分别为38.42％、35.02％、42.43％;经S1、S4、S1+S4处理后,Phe的降解半衰期分别为38.88、29.41、25.63 d,Pyr的降解半衰期分别为64.76、69.02、59.28 d.研究表明,化学作用是控制丝瓜络固定化微生物对多环芳烃吸附速率的主要因素;提高微生物的降解能力能增加对土壤中PAHs迁移的影响;混合菌中真菌与细菌存在协同作用,能提高Phe与Pyr的降解效率.

研究了固定化耐低温真菌-细菌混合菌在低温环境下,对焦化厂污染土壤中的菲(Phe)和苯并[b]荧蒽(BbF)降解的动态变化,利用高通量测序技术分析了降解过程中微生物群落多样性变化.结果表明:在低温条件下固定化混合菌对土壤中Phe 、BbF的去除率远高于游离混合菌与固定化单菌,在60 d的降解周期下,固定化混合菌对土壤中Phe和BbF的降解率分别可达59.61％和45.24％.处理前,土壤中细菌与真菌初始Shannon多样性指数分别为2.79 和0.33,细菌远高于真菌,土壤中土著微生物以细菌为主,高丰度的细菌抑制了真菌的生长代谢.处理后,细菌的 Shannon 多样性指数下降至1.33,真菌的 Shannon 多样性指数增加至1.01,Phe和BbF的降解与细菌多样性呈负相关,且细菌多样性的降低减少了其对真菌的抑制作用.对比分析了处理前后土壤中微生物群落组成的变化,结果表明:投加固定化混合菌后,固定化混合菌中的假单胞菌(Pseudomonas sp.)SDR4 和高山被孢霉(Mor-tierella alpina)JDR7在低温下生长代谢良好,并成为降解过程中的优势菌,其物种相对丰度分别提高至79.84％与58.63％.固定化混合菌对低温环境有良好的耐性,固定化混合菌的投加提高了菌株对多环芳烃(PAHs)的生物利用有效性,改变了土壤中微生物群落的结构和丰度,可应用于低温土壤 PAHs的原位修复.

The combined action of biosorption and biodegradation can achieve a remarkable reduction of organic pollutants. In this study, Pseudomonas sp. SDR4 and Mortierella alpina JDR7 were selected as the representative microorganisms to investigate adsorption and degradation of polycyclic aromatic hydrocarbons (PAHs) in soil using immobilization technology and the subsequent change of the microbial community structure. The results showed that the adsorption capacity of immobilized carriers was much higher than that of dead microorganisms and that the addition of dead microorganisms did not affect the adsorption characteristics of immobilized carriers. The chemical reaction was the major factor controlling the adsorption rate of PAHs in sterilized soil (CK), nonsterilized soil (CK-1), and soil amended with dead body immobilized JDR7 and SDR4 mixed bacteria (MBD). The growth and metabolism of Pseudomonas sp. SDR4 and M. alpina JDR7 are the main reason for enhanced PAH degradation in the soil amended with living body immobilized JDR7, SDR4 mixed bacteria (MB).

分别对丝瓜络进行碱化、酸解、高温高压改性,并将其应用于对水中痕量菲(Phe)、芘(Pyr)的吸附.结果表明,经高温高压改性的丝瓜络表面褶皱最多,比表面积最大,4种丝瓜络对Phe、Pyr的吸附量关系为高温高压改性丝瓜络>碱化丝瓜络>未改性丝瓜络>酸解丝瓜络;4种丝瓜络对Phe、Pyr的吸附过程均服从于准二级动力学,且吸附机制更符合单分子层吸附的Langmuir吸附模型.丝瓜络对多环芳烃的吸附能力的提高或者降低可能与甲基、三键、酰胺、芳香C——C及纤维素等变化有关.

对丝瓜络的物理化学性质(如:颜色,形态,层次结构,成分,化学性质)做出了概述,并指出其在环境污染治理中的优势.同时结合国内外对丝瓜络在环境应用中的研究,介绍了丝瓜络对金属离子、TN、染料以及其他污染物的处理治理能力.针对目前国内对丝瓜络的研究现状,提出了丝瓜络在土壤污染中的应用和丝瓜络物理化学改性意见,并对丝瓜络材料与吸附性关系做出了展望.

从石油污染冻融土壤中筛选出1株细菌(Pseudomonas sp.)和1株真菌(Mortierella alpina),以玉米芯为载体对混合菌进行固定化,研究低温冻融环境下,固定化混合菌对菲(Phe)和苯并[b]荧恩(BbF)污染土壤的生物强化修复作用.通过高效液相色谱法(HPLC)分析Phe和BbF的降解动态,用Michaelis-Menton与Monod动力学方程将结果进行拟合,采用高通测序分析修复过程中微生物群落的变化.结果表明,处理前,冻融土壤中Phe、BbF的浓度分别为(105.4±4.8)、(6.12±1.1)mg·kg-1,60 d修复试验后,固定化混合菌可降解土壤中(56.62±3.21)％的Phe和(38.21±1.82)％的BbF,固定化混合菌对冻融环境有较好的抗性,其降解能力优于游离菌.修复试验中,稳定前期降解速率均高于稳定期降解速率.固定化混合菌的投加,提高了Phe、BbF的降解速率,缩短了Phe、BbF降解的半衰期,反应速率分别提高至2.02、0.65 d-1,半衰期分别缩短至50.17 d和82.12 d;改变了土壤中微生物的群落结构及多样性,其中细菌的多样性和均匀度均降低,多环芳烃(PAHs)的降解与细菌的群落多样性和均匀度呈现负相关;细菌变形杆菌门(Proteobacteria)和真菌鞭毛菌门(Mortierellomycota)成为主要的优势菌门,相对丰富度分别为88.72％和81.15％;细菌假单胞菌(Pseudomonas sp.SDR4)和真菌高山被孢霉菌(Mortierella alpina.JDR7)相对丰度分别上升至80.03％和81.15％,形成了显著的降解真菌-细菌共生优势菌株体系,明显提高了低温土壤中的PAHs污染的修复效果.固定化混合菌可广泛应用于冻融环境下土壤PAHs污染的生物强化修复.

低温条件下,向受多环芳烃污染的土壤投加高效耐冷混合菌(SDR4 +JDR7),可提高土壤中PAHs的去除率,但菌体流失快,重复使用性差,微生物固定化技术在一定程度上可克服这些弊端.考虑到载体选择的微生物亲和性、吸附能力、被富集污染物的生物有效性3个可行性评价参数,本研究选用玉米芯(Y)、花生壳(H)、蛭石(Z)和泥炭土(N)作为供试载体,吸附固定化PAHs高效降解混合菌,观测各处理组对土壤中菲(Phe)、芘(Pyr)、苯并[a]芘(BaP)的降解,并采用Michaelis-Menton和Monod动力学模型对降解结果进行拟合.结果表明:60 d后,4种载体材料固定化菌Y-(SDR4+ JDR7)、H-(SDR4+ JDR7)、Z-(SDR4+JDR7)、N-(SDR4+JDR7)的降解能力优于游离菌.Z-(SDR4+ JDR7)的降解效果最优,其对Phe、Pyr和BaP去除率分别为64.38％、48.71％和40.19％,其次为Y-(SDR4+JDR7),去除率分别为58.49％、45.91％和37.07％.Y-(SDR4+ JDR7)对Phe的降解速率最大,为0.60 d-1,较游离菌高7.7％;Z-(SDR4+JDR7)对Pyr和BaP的降解速率最大,分别为0.54和0.20 d-1,较游离菌分别提高11.83％、10.85％.Z-(SDR4 +JDR7)对高环BaP的降解半衰期最短,为86.64 d.本研究可为北方寒冷地区PAHs污染的土壤修复提供借鉴.

In order to search for efficient PAH degrading bacteria in the natural environment,and to apply them in remediation of PAH contaminated soil in northern cold area,a cold resistant bacterium,which could use humic acid (HA) adsorbed PAHs as sole carbon and energy sources was screened from freezing-thawing soils of Shenfu Irrigation Area.This bacterium was identified as Pseudomonas sp.SDR4 with physiological-biochemical characterization and 16S rDNA sequencing analyses.its degradation ability for of HA adsorbed PAHs was studied.The results showed that this Pseudomonas sp.SDR4 can degrade phenanthrene,pyrene,and benzo(a) pyrene in the soil with 73.88％,88％ and 49.39％ of efficiency respectively.Addition of HA enhanced biodegradation rate of phenanthrene,pyrene and benzo(a) pyreneby 15.9％,13.8％ and 8.6％ respectively.The enhancements of biodegradation occurred at the early stage of HA addition,especially in the first week.But were not so signficant in the later stage.If Pseudormonas sp.SDR4 is selected in the cold region as a immobilised strain,addition of HA can improve its remediation efficiency.This study provides new immobilized strain for remediation of PAH contaminated soil in northern cold area.