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1. 题目: Synergistic effect and mechanism analysis of biochar regulator on heavy metal passivation and microplastic degradation in sewage sludge compost
文章编号: N25050912
期刊: Journal of Hazardous Materials
作者: Xinwei Sun, Mukesh Kumar Awasthi
更新时间: 2025-05-09
摘要: Heavy metal passivation and microplastic in sludge threatens environment and caused human health risks, and thus necessary to find effective remediation strategies. To solve this issue, the synergistic effect of biochar on pollutants remediation during sludge composting is still not well explored. In this study, different doses of cotton stalk biochar (0%, 2.5%, 5%, 7.5%, 10% CSB; and labeled T1-T5) were applied to sludge composting to investigate the synergistic effect of CSB on pollutants (copper, zinc, and microplastics) and explore the influence mechanism. Results showed that CSB could effectively increase the yield of humic acid (15.85~22.08 g/kg) and reduce the content of extractable copper (59.37~81.10%) and extractable zinc (27.07~51.45%). Among them, T5 was superior in the passivation of heavy metals. In addition, CSB optimized the environmental factors to increase the degradation rate of microplastics by 16.23%~57.86%, exhibiting dose-dependent improvement. The microbiological analysis showed that CSB could decrease the relative abundance of Firmicutes (29.16~59.20%) and increase the relative abundance of Proteobacteria (14.10-33.48%), Actinobacteriota (2.55~46.25%) and Ascomycota (11.36~65.71%) in the high temperature stage of compost. For correlation analysis, T4 and T5 could better enhance the positive correlation between environmental factors and microorganisms. In summary, T5 could minimize the content of heavy metals and microplastics in compost products, and it had the highest level of application value. Hence, this study is of great significance for reducing the pollutant risk of sludge composting.

2. 题目: Simultaneous Elucidation of the Chemodiversity of Dissolved Organic Matter and Quantitation of Trace Organic Contaminant Sucralose by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry
文章编号: N25050911
期刊: Analytical Chemistry
作者: Qian You, Yanhui Cheng, Qing-Long Fu, Guodong Cao, Jibao Liu, Manabu Fujii, Lee Blaney, Pingqing Fu, Yanxin Wang
更新时间: 2025-05-09
摘要: Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) has become a cutting-edge technique for molecular characterization of dissolved organic matter (DOM) and trace organic contaminants. Nevertheless, FT-ICR MS is rarely applied to simultaneously elucidate DOM chemodiversity and quantify the concentrations of trace organic contaminants. Compared to conventional solid-phase extraction (SPE), pH-dependent fractionation of DOM molecules using a sequential SPE strategy significantly enhanced the recovery of dissolved organic carbon and yielded more chemical formulas for DOM from environmental samples (p < 0.05). The sequential SPE at circumneutral pH provided exclusive isolation of some hydrogen-rich and oxygen-poor molecules, caused a 5-fold reduction in matrix effects, and improved the detection limits for organic contaminants. The chemical structure of a typical wastewater indicator, sucralose, was successfully validated using FT-ICR MS analysis with tandem mass spectrometry and hydrogen/deuterium exchange measurements. With the standard addition method, the limits of detection and quantitation of FT-ICR MS for sucralose in DOM extracts isolated at circumneutral pH were estimated to be 0.26 and 0.87 μg/L, respectively. The concentrations of sucralose in a representative urban lake measured by FT-ICR MS (e.g., 0.9–4.1 μg/L) were comparable to those determined by liquid chromatography coupled to an Orbitrap mass analyzer. The findings of this study expand application of FT-ICR MS in environmental research by highlighting its potential for identifying trace organic contaminants, quantifying their concentrations, and elucidating the chemodiversity of DOM to inform contaminant sources in aquatic systems.

3. 题目: Effect of organic carbon enrichment on halogenated organic pollutants in wetland sediments of the Yellow River Estuary and Jiaozhou Bay, China
文章编号: N25050910
期刊: Environmental Research
作者: Zi-Cen Zuo, Shan-Shan Liu, Jie Ni, Ya-Li Cao, Zhen He, Gui-Peng Yang
更新时间: 2025-05-09
摘要: Coastal wetlands, vital ecosystems, are threatened by anthropogenic activities and act as significant sinks for halogenated organic pollutants (HOPs). Despite the persistent toxicity and ecological risks associated with HOPs, their spatial distribution and environmental behavior in coastal sediments, particularly the role of total organic carbon (TOC) in modulating their fate, remain poorly understood. We investigated the contamination characteristics of 25 halogenated polycyclic aromatic hydrocarbons (HPAHs) in the surface sediments of two coastal wetlands, the Yellow River estuary and Jiaozhou Bay, with different environmental backgrounds. HPAH concentrations were higher in Jiaozhou Bay (23.81-121.78 ng g^-1, mean 50.58 ± 28.85 ng g^-1) than in the Yellow River estuary (14.69-30.12 ng g^-1, mean 23.48 ± 5.42 ng g^-1), influenced by hydrodynamic conditions and anthropogenic activities. While TOC showed a weak correlation with HPAHs under the low TOC levels and dynamic sedimentary conditions of the Yellow River estuary, it showed significant positive correlations with most HPAHs in Jiaozhou Bay, where limited water exchange enhanced pollutant accumulation. Risk assessment based on the risk quotient (RQ) indicated that the overall RQ was lower in Jiaozhou Bay, despite the higher mean HPAH concentration (2.2 times higher than in the Yellow River estuary), which may be due to the higher TOC content that enhances adsorption and reduces bioaccessibility. Fish and Daphnia in both wetlands were almost always at minimal risk levels, although localized elevated risks may occur in areas with higher pollution loads. These findings highlight the importance of integrating TOC and hydrodynamic factors in coastal pollution management.

4. 题目: A comprehensive sulfate and DOM framework to assess methylmercury formation and risk in subtropical wetlands
文章编号: N25050909
期刊: Nature Communications
作者: Brett A Poulin, Michael T Tate, Sarah E Janssen, George R Aiken, David P Krabbenhoft
更新时间: 2025-05-09
摘要:

Wetlands play a vital role in contaminant cycling and uptake. Understanding how sulfate (SO₄^2‒) influences the conversion of inorganic mercury (Hg(II)) to toxic methylmercury (MeHg) is critical for predicting wetland responses to land use and climate change. Here, we sampled surface and pore waters across SO₄^2‒ gradients in three freshwater Everglades wetlands to assess linkages between SO₄^2‒, MeHg, dissolved organic matter (DOM), and inorganic sulfide (S(‒II)). Increasing SO₄^2‒ concentrations increase S(‒II) and DOM concentrations and DOM aromaticity. MeHg concentration show a unimodal response to surface water SO₄^2‒, which reflect high Hg(II) methylation at low-to-intermediate SO₄^2‒concentration (2-12 mg/L) and low Hg(II) methylation at higher SO₄^2‒concentrations ( > 12 mg/L). MeHg concentrations in surface waters correlate positively with MeHg concentrations in prey fish. The coherent biogeochemical relationships between SO₄^2‒ and MeHg concentrations and biologic uptake improve MeHg risk assessment for aquatic food webs and are globally relevant due to anthropogenic and climate-driven increases in SO₄^2‒.

5. 题目: Effects of dissolved cations, dissolved organic carbon, and exposure concentrations on per- and polyfluoroalkyl substances bioaccumulation in freshwater algae
文章编号: N25050908
期刊: Environmental Pollution
作者: Xiaoyan Yun, Maya Hillis, Erica Alston, Christopher M Sales, Daniel E Spooner, Marie J Kurz, Rominder Suri, Erica R McKenzie
更新时间: 2025-05-09
摘要: Per- and polyfluoroalkyl substances (PFAS) have attracted global attention because of their persistence, toxicity, bioaccumulation potential, and associated adverse effects. As important primary producers, freshwater algae constitute the base of the food web in freshwater aquatic ecosystems. However, the effects of key environmental factors on PFAS uptake and bioaccumulation in freshwater algae have not been thoroughly studied. In this study, three bioaccumulation experiments were conducted to evaluate the influence of dissolved cations, dissolved organic carbon, and exposure concentrations on PFAS bioaccumulation in algae. Among the 14 studied PFAS, seven long-chain PFAS tended to bioaccumulate in algae. Elevated divalent cations (Ca²⁺ and Mg²⁺) and dissolved organic carbon did not significantly change the algal bioconcentration factors (BCFs) of PFAS, suggesting complexity of the interactions among PFAS, environmental factors, and biotic activities. Additionally, increasing exposure concentrations (0.5, 1, 5, and 10 μg/L of each PFAS) increased PFAS concentrations in algae but decreased the BCF values. This indicated that attention should be paid to the application of BCFs in future studies, including ecological risk assessment. Moreover, fluorotelomer sulfonic acids (FTSs) were incompletely recovered, suggesting that biotransformation occurred. Further studies should be conducted to evaluate whether algae play a role in FTSs biotransformation and to determine the mechanisms. Studying the impacts of key environmental factors on PFAS bioaccumulation in algae is crucial for understanding the bioaccumulation processes that occur at the lowest trophic level and that eventually affect the dynamics of entire aquatic ecosystems.

6. 题目: Risk assessment of soil erosion with RUSLE using geographic information system and organic carbon and total nitrogen loadings of suspended sediment in Sogutlu Stream Watershed of Trabzon, Turkey
文章编号: N25050907
期刊: Environmental Earth Sciences
作者: Necla KORALAY, Ömer KARA
更新时间: 2025-05-09
摘要:

Erosion is a global problem that negatively affects the land structure, soil and crop productivity, water quality, and socio-economic stability of watersheds. Assessing the amount of soil loss and sediment delivery ratio (SDR) in a watershed is important for planning soil and water conservation efforts, as this information assists in evaluating erosion risk. In this study, soil loss and SDR values were determined in the Söğütlü Stream Watershed, and an erosion risk map was created. Using the RUSLE method in the ArcGIS program, the transported soil amount and SDR were calculated. Soil samples from the top 0–30 cm layer were collected from 123 points to calculate RUSLE-K. Annual suspended sediment (SS), organic carbon (C), and total nitrogen (TN) in SS were directly measured. Monthly water samples were collected from August 2019 to July 2020. The results showed an average soil loss of 1.91 tonsha⁻¹ year⁻¹,annual soil loss of 52,209.01 tonsyear⁻¹, an SDR of 0.43, and a sediment yield of 0.82. The estimated sediment reaching the streams was 22,449.87 tonsyear⁻¹, with C and TN calculated at 312.95 and 41.936 tonsyear⁻¹. The measured sediment was lower at 12,549.82 tonsyear⁻¹, with C and TN at 174.96 and 23.44 tonsyear⁻¹. The findings of this study hold significant suggestions for future studies on soil and water conservation using ARCGIS, offering guidance to reduce soil erosion and improve water quality.

7. 题目: Soil Organic Carbon Sequestration Potential, Storage, and Influencing Mechanisms in China
文章编号: N25050906
期刊: Land Degradation & Development
作者: Jinhua Cao, Zipeng Zhang, Jianli Ding, Liangyi Li, Junchen Ai, Yuanting Yang, Chuanmei Zhu, Xiangyu Ge, Jingzhe Wang
更新时间: 2025-05-09
摘要: The soil organic carbon sequestration potential (SOC_sp) has important implications for the global carbon cycle and responses to climate change. However, there is a dearth of spatial information specifically for China within this field, and our knowledge regarding the factors influencing SOC_sp remains somewhat limited. To solve this problem, this study utilized legacy soil data collected in the 1980s (1979–1984s), combined with climatic landscape zoning, and adopted digital soil mapping techniques to produce spatial prediction models of the density of soil carbon sequestration potential for five designated depths. The results showed that the accuracy of the top soil (0–30 cm) model was higher than that of the subsoil (30–100 cm) model. SOC_sp was highest in northwestern, northern, and eastern China and lowest in the southeastern Tibetan Plateau and northeastern China. Scale- and location-specific effects of environmental factors on SOCs were observed, with two-factor effects being stronger than those of their one-factor counterparts. Spatial differentiation characteristics of drivers between topsoil and subsoil layers show significant climatic zonal differences. In the topsoil layer, climate and vegetation are the dominant factors in the arid zone, while the semi-arid zone is mainly regulated by vegetation and land use; in the subsoil layer, climate and land use together dominate SOC_sp in the arid and semi-arid zones. In this study, we provide data support for the SOC_sp pathway for climate change mitigation processes, while emphasizing the importance of in-depth studies on the mechanisms of SOC_sp dynamics through its driving mechanisms.

8. 题目: Traditional gel nanofiltration membranes doped with ball-milled crayfish shell biochar for high-selectivity dye/salt separation
文章编号: N25050905
期刊: Journal of Environmental Chemical Engineering
作者: Xu Yang, Dawei Zhang, Yingwen Xue, Jiatong Liang, Zhiguang Tu, Ying Lv, Zhilun Zhang
更新时间: 2025-05-09
摘要: The balance between selectivity and permeability in nanofiltration membranes significantly limits the broader application of nanofiltration technology. Here, we propose an innovative biochar-doped composite gel membrane to address this limitation. Ball-milled crayfish shell biochar (BCFS800) was incorporated into sodium alginate (SA) hydrogel to construct a high-performance NF membrane. The BCFS800, with its hierarchical pore structure (289.7 m²/g surface area) and abundant oxygen-containing groups, created additional water channels while enhancing dye adsorption. The crosslinking between Ca²⁺ in BCFS800 and SA carboxyl groups improved mechanical stability, enabling stable operation under pressures up to 0.35 MPa.When tested with a mixed solution of Congo Red dye and sodium chloride, the composite membrane achieved a remarkable selectivity of 149.2 (vs. 34.3 for the control), with a water flux of 6.5 LMH/bar (61% higher than the control). Notably, NaCl rejection decreased to 4.54% (vs. 7.56% for the control), demonstrating exceptional dye/salt separation capability. These results indicate that the composite biochar gel NF membrane offers efficient, stable separation for dye molecules and inorganic salts, with significant potential for future water treatment applications.

9. 题目: MoleTrans: Browser-Based Webtool for Postanalysis on Molecular Chemodiversity and Transformation of Dissolved Organic Matters via FT-ICR MS
文章编号: N25050904
期刊: Environmental Science & Technology Letters
作者: Jibao Liu, Bei Zhang, Qing-Long Fu, Toshihiro Isobe, Rongjun Gao, Yuansong Wei, Eunsang Kwon, Zhineng Hao, Wei An, Rong Qi, Manabu Fujii
更新时间: 2025-05-09
摘要: Dissolved fractions of organic matter in natural and anthropogenic sources, also known as dissolved organic matter (DOM), play crucial roles in natural and engineering processes. Application of the Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS) has expanded dramatically for the molecular characterization of DOM in various research communities. However, data processing/mining on the detected tens of thousands of molecular formulas is complex. Here, we introduced a browser-based webtool (MoleTrans) for flexible and comprehensive postanalysis on a formula-assigned data set from FT-ICR MS. MoleTrans includes the classical but fundamental analysis/visualization techniques (e.g., chemodiversity, multivariate statistics, van Krevelen diagrams, formula composition plots, Kendrick Mass Defect (KMD) based homologous series analysis). Users can explore the putative molecular transformation relations in single or multiple samples using a Paired Mass Distance (PMD) network in a flexible manner (e.g., user-defined mass errors and reference transformation groups, etc.). This unique tool also supports the machine learning (ML) workflow (data processing and training models) for explaining the molecular transformation behaviors between samples (e.g., exploring the disappeared, resistant, and newly appeared formulas during the transformation). Therefore, MoleTrans provides the opportunity to unravel the molecular fingerprint in DOM mixtures in a comprehensive, flexible, and reproducible way.

10. 题目: Mechanism of manganese ion-driven degradation of organic matter in waste leachate by key microbial communities
文章编号: N25050903
期刊: Separation and Purification Technology
作者: Bo Zhu, Zihao Fan, Hua Zhang, Tao Luo, Yong Zhang, Hao Liu
更新时间: 2025-05-09
摘要: Manganese ions (Mn²⁺), commonly present in waste leachate, significantly influence anaerobic biological treatment systems. Understanding their effects on key microorganisms and elucidating the mechanisms of organic matter degradation are critical for process optimization. This study investigated microbial community dynamics using 16S rRNA sequencing coupled with statistical analysis, while structural equation modeling (SEM) was employed to decipher the driving mechanisms of Mn²⁺ on organic matter metabolic pathways. Results demonstrated that low Mn²⁺ concentrations (100–400 mg/L) enhanced anaerobic treatment efficiency, whereas higher concentrations (500–600 mg/L) exhibited inhibitory effects. Microbial analysis identified 23 key genera in the anaerobic system, including Defluviimonas, Acidibacter, NK4A214_group_1, Anaerofustis, Bd_7_clade, Clostridium_sensu_stricto_12, Fontibacter, Chelativorans, Fastidiosipila, and Tissierella,which dominated metabolic processes. SEM revealed Mn²⁺ exerted the strongest inhibitory effect on non-organic acid metabolic pathways (standardized path coefficient: −0.7416), while promoting organic matter degradation primarily through valeric acid metabolic pathways (standardized path coefficient: 0.6205). These insights underscore that strategic regulation of influent Mn²⁺ levels can amplify metabolic diversity, ultimately enhancing organic removal in leachate treatment systems.

11. 题目: Combined Application of Humic Acid and Attapulgite Improves Physical Structure and Nutrients in Coastal Saline-Alkali Soils
文章编号: N25050902
期刊: Land Degradation & Development
作者: Weibin Zhao, Shufeng Wang, Li Tang, Jiang Xiao, Guangcai Chen
更新时间: 2025-05-09
摘要: Coastal soils are subject to salinization, a process that degrades soil structure, exacerbates nutrient leaching, and depletes soil organic matter. Both organic fertilizers and clay amendments have been shown to play a key role in soil structure, nutrient availability, and soil health. The different dosages (0%, 3%, and 6%) of humic acid (HA3 and HA6) and attapulgite (AT3 and AT6) alone or in combined application (HAT3 and HAT6) on the quality of coastal saline-alkali soil were studied. The results showed that in terms of soil physiochemical properties, the combination of HA and AT (HAT) significantly (p < 0.05) improved soil moisture content and soil CEC by 4.01%–5.25% and 53.45%–401%, and significantly (p < 0.05) reduced soil salinity and soil Na⁺ content by 25.38%–45.18% and 27.57%–38.16%, compared to the control. In terms of soil nutrient content, HAT treatments significantly (p < 0.05) improved the contents of soil TN, AP, and SOC by 15.25%–26.88%, 19.67%–32.11%, and 73.71%–99.25%, compared to the control, respectively. Furthermore, the soil quality indexes (SQI) constructed based on PCA analysis indicated that the improvement effect of each treatment on soil quality ranked as HAT6 > HA6 > HAT3 > HA3 > AT6 > AT3 > Control. In short, HAT treatment can produce larger surface area and more elements (e.g., N, P, and Ca) content through the combination of HA and AT, accelerate salt leaching, and increase soil nutrient content by promoting soil aggregate formation and ion exchange capacity, thereby improving soil quality more than the single application of HA and AT. These results offer valuable insights for the formulation of ecological restoration strategies targeting large-scale coastal saline-alkali terrains.

12. 题目: Biochar derived from feedstock with high lignin content leads to better soil improvement performance in red soils: from the perspective of soil microbial regulation and carbon stabilization
文章编号: N25050901
期刊: Environmental Geochemistry and Health
作者: Bowei Lv, Bing Ma, Yulong Li, Li Wu, Min Huang, Xiaoman He, Jianming Xue, Lie Yang
更新时间: 2025-05-09
摘要:

Red soil in southern China has a significant potential for carbon sequestration enhancement. Therefore, this study aimed to explore more effective biochar options to enhance the soil microbial environment and investigate their effects on soil carbon cycling. Three types of biochar were prepared and analyzed: maize stover biochar (Maize-BC, low lignin content), cotton stover biochar (Cotton-BC, high lignin content), and sludge biochar (Sludge-BC, no lignin content). The structure of the soil microbial community and carbon dynamics were comprehensively analyzed. The three biochars increased soil inorganic carbon, stable organic carbon, microbial carbon, and dissolved organic carbon by 30.1%–75.5%, 37.6%–44.0%, 88.4%–248.1%, and 4.3%–73.9%, respectively. Maize-BC with lower lignin content exhibited higher abundance and diversity in soil microbial communities compared to other treatments. In contrast, the addition of Cotton-BC with higher lignin content resulted in a shift mainly in the phylum Actinobacteria and Proteobacteria. Overall, the soil changes induced by cotton stover were more favorable for promoting a shift in the microbial community structure toward a lower carbon cycle, enabling microorganisms to better regulate or control the soil carbon cycle. This study offers a promising approach for future research focused on enhancing soil fertility and reducing soil carbon emissions.

13. 题目: Enhancing soil labile organic matter through oilseed rape-rice rotation and straw returning in paddy-upland systems
文章编号: N25050813
期刊: Plant and Soil
作者: Shuntao Zhang, Tao Ren, Yating Fang, Jian Zhao, Jun Zhu, Wen-feng Cong, Hans Lambers, Jianwei Lu
更新时间: 2025-05-08
摘要:

Background and aims

Soil labile organic matter (LOM) plays a vital role in enhancing soil productivity and fertility. However, the annual variability of LOM content and structure under diverse crop rotation and fertilization practices remains insufficiently investigated.

Methods

This 5-year field study investigates the impact of different fertilization treatments—no fertilization (CK), conventional fertilization (CF), recommended fertilization (RF), and recommended fertilization with straw returning (RF + S)—on the content and structure of LOM under oilseed rape-rice (OR) and wheat-rice (WR) cropping systems.

Results

Our results showed that the effect of rotation type on soil LOM was most pronounced during the upland season, while fertilization effects were significant across the entire annual paddy-upland rotation system. During the upland season, the OR rotation, excluding the CF treatment, resulted in significantly higher increases in soil easily oxidizable organic carbon (EOC), particulate organic carbon (POC), and particulate nitrogen (PN) compared to the WR rotation with same fertilization treatments. The RF and RF + S treatments significantly enhanced soil LOM contents in both rotations. Excitation Emission Matrix (EEM) and UV–Visible absorption analyses indicated that the OR rotation had a higher degree of humification, a more aromatic structure, and greater levels of colored dissolved organic matter (DOM) than the WR rotation.

Conclusions

In summary, the OR rotation, especially with straw returning, is an effective strategy for enhancing both the content and structural stability of LOM. This approach promotes improved soil quality and offers a sustainable solution for long-term fertility management in paddy-upland rotations.

Highlights

• Rotation and fertilization practices jointly affect soil LOM content and structure.

• Oilseed rape in paddy-upland rotation improves LOM content and composition.

• The LOM difference between OR and WR rotations mainly appears in the upland season.

14. 题目: Green Manure Coupled With Straw Returning Increases Soil Organic Carbon via Decreased Priming Effect and Enhanced Microbial Carbon Pump
文章编号: N25050812
期刊: Global Change Biology
作者: Guopeng Zhou, Guilong Li, Hai Liang, Rui Liu, Zhengbo Ma, Songjuan Gao, Danna Chang, Jia Liu, David R Chadwick, Davey L Jones, Weidong Cao
更新时间: 2025-05-08
摘要: Green manuring and crop straw returning are widely used to increase soil organic carbon (SOC) sequestration, while the pathways and drivers in native SOC mineralization and new SOC formation after implementing these practices remain unclear. Here, through a 10-locations' network field experiment in southern China, the effects of green manuring (Mv), rice straw returning (Rs), and their combination (MR) on soil C sequestration efficiency (CSE) were evaluated. A microcosmic experiment was performed to trace the components and participants of SOC mineralization and formation under the three practices. The network experiment showed that Mv, Rs, and MR annually improved SOC stock by 119.7, 477.0, and 830.2 kg C ha⁻¹, respectively, with MR having the highest CSE of 23.1%, followed by Rs (17.7%) and Mv (13.3%). The microcosmic experiment further revealed that the highest CSE in MR most likely resulted from the low mineralization of native SOC (positive priming effects, PE) and great formation of new SOC through microbial C pump (MCP). Therein, MR mainly downregulated the K-strategists of the microbial community (e.g., Gaiellales) to yield negative PE on recalcitrant native SOC, such as protein/amino sugar- and lignin-like molecules; meanwhile, MR had the highest bacterial and fungal MCPs, which were, respectively, led by r-strategists (e.g., Sporobacter) and molds (e.g., Cladosporium). The study highlights the advantages of mixing low- (Rs) and high-quality (Mv) residues for efficiently increasing SOC sequestration and firstly discovers the core microbes that dominate the mineralization and formation of SOC in paddy fields.

15. 题目: Effect of enzyme-induced carbonate precipitation (EICP) combined with biochar on lead-contaminated soil solidification and plant growth
文章编号: N25050811
期刊: Journal of Environmental Chemical Engineering
作者: Hanliang Bian, Yangke Ma, Peirui Ji, Guanghui Zhang, Zhenshan Liu, Ya Chu, Jianwei Zhang
更新时间: 2025-05-08
摘要: This study evaluates the remediation efficacy of Enzyme-Induced Carbonate Precipitation (EICP) combined with biochar on lead (Pb)-contaminated soil and its influence on the cultivation of Brassica rapa subsp. chinensis. Three treatments were compared: EICP-biochar synergistic treatment (EB), a biochar-only amendment (B), and an EICP-only application (E), with untreated Pb-contaminated soil serving as the negative control (CK). Soil physicochemical properties and Pb speciation were analyzed before and after remediation. Results demonstrated that the EB treatment achieved significantly higher Pb immobilization efficiency (90.35%) compared to EICP-only (72.80%) and biochar-only (56.63%) treatments. In pot experiments, the EB treatment markedly enhanced Chinese cabbage growth, with stem and leaf length increasing by 340%, and aboveground and underground fresh weights increasing by 421.62% and 180.17%, respectively. The germination index in EB-amended soils exceeded the threshold for plant growth (80%), indicating phytotoxicity mitigation and improved soil quality. Notably, EB treatment reduced Pb bioaccumulation factors by 90.32% in leaves and 89.32% in roots, respectively, compared to the control. The findings demonstrate that the integration of EICP and biochar achieves synergistic immobilization and bioavailability suppression of heavy metals, offering a promising strategy for the remediation of Pb-contaminated soils.

16. 题目: Advancing the comprehensive understanding of soil organic carbon priming effect: definitions, mechanisms, influencing factors, and future perspectives
文章编号: N25050810
期刊: Environmental Geochemistry and Health
作者: Shengman Zhang, Ziyuan Zhang, Fushun Wang, Xiangfeng Huang, Xueping Chen, Yuchun Wang, Chunyang Li, Hui Li
更新时间: 2025-05-08
摘要:

The soil carbon (C) priming effect (PE), an important phenomenon in soil C cycle research, has garnered extensive attention in recent years. Soil C PE refers to the stimulation or inhibition of the original soil organic C (SOC) decomposition rate by newly added organic matter in the soil. Its mechanism of action involves the activity of soil microorganisms. Fresh organic matter input provides an additional source of energy and nutrients for soil microorganisms, prompting changes in microbial community structure and activity, which in turn affects SOC decomposition. Easily decomposable organic matter may stimulate rapid microbial growth and metabolic activity of microorganisms, thereby the decomposition accelerating of original SOC and producing a positive PE, whereas recalcitrant organic matter may lead microorganisms to preferentially utilise the newly added C source, thereby inhibiting original SOC decomposition and producing a negative PE. There are numerous factors influencing soil C PE, including organic matter properties such as chemical composition, C:N ratio, and lignin content; soil environmental factors such as temperature, humidity, and pH value; and land-use patterns and vegetation types. Research on soil C PE is crucial for an in-depth understanding of the soil C cycle, the accurate assessment of dynamic changes in the soil C pool, and the development of sustainable soil management strategies. This study introduces the definition, change mechanism, influencing factors, and research methods of soil C PE and elaborates on the status and deficiencies of PE research, which is helpful for predicting soil C responses to global climate change and provides a scientific basis for improving soil fertility and reducing greenhouse gas emissions.

17. 题目: Microbial processes dominate DOM degradation in alpine karst lakes over photochemical effects
文章编号: N25050809
期刊: Environmental Research
作者: Qinqin You, Hanyong Zeng, Muhammad Ibrar, Dalin Zhu, Demeng Zhao, Yutao Cao, Yunde Zhang, Yanbao Lei, Geng Sun
更新时间: 2025-05-08
摘要: Karst lakes, known as major inorganic carbon sinks, have recently been recognized as stable reservoirs of organic carbon. However, the mechanisms governing organic carbon stability in these systems remain poorly understood. In particular, the role of dissolved organic matter (DOM) degradation in shaping DOM composition and stability through photochemical and microbial pathways has not been well characterized. By combining fluorescence spectroscopy and FT-ICR-MS with microbial high-throughput sequencing, we conducted a controlled experiment on water- and sediment-derived DOM from a Jiuzhaigou karst lake, employing light-only, microbe-only, and combined treatments. While photochemical processes contribute to changes in DOM properties, microbial activity primarily dominates DOM degradation under photo-biological conditions. Specifically, photochemical processes primarily degraded aromatic compounds into aliphatic forms, resulting in reduced O/C ratios and increased H/C ratios. In contrast, microorganisms preferentially degraded compounds with low O/C and high H/C ratios. Notably, DOM containing nitrogen and sulfur exhibited higher biological reactivity, whereas CHO compounds were more likely to contribute to recalcitrant DOM pools. Furthermore, high-molecular-weight DOM restricted microbial diversity, whereas DOM with high O/C ratios facilitated more complex microbial networks. This study provides insights into the stability of water and sediment DOM and the mechanisms driving its degradation, offering a deeper understanding of C cycling in karst ecosystems.

18. 题目: Radiocarbon analysis reveals decomposition of old soil organic carbon into dissolved inorganic carbon in a subtropical mangrove ecosystem
文章编号: N25050808
期刊: Limnology and Oceanography
作者: Wataru Nakamura, Kojin Tsuchiya, Kenta Watanabe, Toshihiro Miyajima, Yosuke Miyairi, Yusuke Yokoyama, Phyo Thet Naing, Tomohiro Kuwae, Jun Sasaki
更新时间: 2025-05-08
摘要: The outwelling of remineralized dissolved inorganic carbon (DIC) from the subsurface soil layer through tidal pumping has recently been noted for its importance in the blue carbon budget of mangroves. However, the age of soil organic carbon (SOC) that has been decomposed into DIC remains uncertain. In this study, two distinct models (a two endmembers model and three endmembers model) were utilized to verify the age of the decomposed SOC, employing radiocarbon (Δ14C) as a tracer. We conducted a 24‐h measurement of DIC and DIC isotopes (δ13CDIC and Δ14CDIC), in addition to vertical profiles of Δ14C of SOC, in a subtropical mangrove ecosystem in Japan. The Δ14C expected for the source SOC that decomposed into DIC exhibited a comparable trend for the two distinct models, with mean values ranging from −86.6‰ to −16.8‰. The Δ14C values were converted to calendar age using the OxCal program, with the calibration curve from IntCal20 being employed. This conversion revealed that DIC in the mangrove creek originated from SOC buried over a century ago. Given that mangroves are confined to the intertidal zone, it is likely that there are spatial constraints on the burial of SOC in mangrove ecosystems. Consequently, the transition from SOC to the DIC carbon pool in the ocean could be a key process in supporting long‐term carbon sequestration over millennia.

19. 题目: Biochar interacted with organic compounds from digestate in controlling N2O emissions.
文章编号: N25050807
期刊: Journal of Environmental Management
作者: Yunyun Zheng, Lynette K Abbott, Nanthi Bolan, Hangwei Hu, Sasha N Jenkins, Bede S Mickan
更新时间: 2025-05-08
摘要: Treating biochar with digestate can form a C- and N-enriched biochar fertilizer, but its role in controlling N2O emission from soil with different pH is unclear. This study assessed N2O emission from rhizosphere soil after growing ryegrass with urea, urea plus biochar, solid digestate, and digestate-incorporated biochar, with and without liming. The abundances of bacteria, fungi, two nitrification genes (bacterial amoA; archaeal amoA), and four denitrification genes (nirK, nirS, nosZ for clade I and nosZII for clade II) were quantified using quantitative PCR. Bacterial community composition was characterized using amplicon sequencing. Solid digestate and urea plus biochar decreased N2O emission by 48% and 56%, respectively, relative to urea under non-liming. This corresponded to the increased bacterial abundance and greater increases in N2O-consuming (nosZ and nosZII) than N2O-producing (archaeal amoA, nirK, nirS) gene abundances. Digestate-incorporated biochar decreased N2O emission by 75% compared to solid digestate, with decreased nirK gene abundance and increased prevalence of the denitrifier Dokdonella. Liming resulted in the lowest N2O emissions and highest nosZII gene abundance among all treatments. This study demonstrated the value of incorporating biochar in digestate in reducing N2O emission while enhancing plant nutrition.

20. 题目: Drivers of dissolved organic matter processing in subterranean estuaries
文章编号: N25050806
期刊: Limnology and Oceanography Letters
作者: Elisa Calvo‐Martin, Xosé Antón Álvarez‐Salgado, María José Pazó Fernández, Vanesa Vieitez Dos Santos, J Severino P Ibánhez
更新时间: 2025-05-08
摘要: Subterranean estuaries (i.e., seawater‐fresh groundwater mixing zones at coastal aquifers) are highly reactive boundaries between continental groundwater and coastal surface seawater. Because particulate organic matter is retained in shallow sediments, internal microbial transformations rely on dissolved organic matter (DOM) supply and bioavailability. Here, we investigated DOM carbon content and optical characteristics in two nearby subterranean estuaries with contrasting oxygenation. Coastal organic carbon processing in the anoxic subterranean estuary resulted in the export of DOM enriched in recalcitrant compounds compared to the oxygenated one, which was a net sink of DOM. This contrasting behavior was not driven by opposite redox conditions but from the fast transfer of labile DOM and oxygen to the beach interior of the oxygenated subterranean estuary. There, heterotrophic processes, which rely almost exclusively on DOM, are enhanced, resulting in net DOM consumption prior discharge to surface waters.