环境科学最新文献

{"title":"[Bacterial Community Structure and Functional Characteristics of Soil in <i>Carex</i> Tussock Marsh Wetland with Different Degradation Levels].","authors":"Miao-Miao Zhang, Man-Yin Zhang, Jing Li, Li-Juan Cui, Zi-Liang Guo, Wei-Wei Liu, He-Nian Wang, Da-An Wang","doi":"10.13227/j.hjkx.202403046","DOIUrl":"https://doi.org/10.13227/j.hjkx.202403046","url":null,"abstract":"<p><p>To explore the characteristics and influencing factors of soil bacterial communities in degraded marsh wetlands, we divided the <i>Carex</i> tussock marsh wetland in northeast China into three degradation degrees： non-degraded （ND）, mildly degraded （LD）, and heavily degraded （HD）. High-throughput sequencing technology and PICRUSt bacterial function prediction tools were used. We analyzed the soil environmental characteristics and soil microbial community structure characteristics of degraded wetlands and explored the influencing factors of microbial changes in degraded wetlands. The results showed that： ① The soil pH value was generally neutral to alkaline in general. With increasing degrees of degradation, the contents of soil organic carbon, total nitrogen, total carbon, and zinc decreased significantly （<i>P&lt;</i>0.05）, while the content of total potassium increased significantly （<i>P&lt;</i>0.05）. ② The dominant bacterial groups included Proteobacteria, Acidobacteriota, and Gemmatimonadota in the degraded wetlands. ③ The Alpha diversity of soil bacterial communities increased significantly with the increases in wetland degradation degree （<i>P&lt;</i>0.05）, and there was a significant difference between degraded （LD and HD） and non-degraded （ND） wetlands in bacterial community composition.④ From the perspective of bacterial community functions, the primary metabolic functions, such as metabolism, genetic information processing, cellular processes, and environmental information processing, were significantly weakened with the increasing degree of degradation （<i>P&lt;</i>0.05）. The main secondary functions such as amino acid metabolism, carbohydrate metabolism, biodegradation, and metabolism of exogenous substances were significantly weakened （<i>P&lt;</i>0.05）. ⑤ Pearson correlation analysis showed that the change in soil bacterial Alpha diversity was significantly correlated with the contents of soil total nitrogen, total carbon, and organic carbon and the physical characteristics （diameter, height, and number） of <i>Carex</i> hummocks （<i>P&lt;</i>0.05）. RDA results showed that pH value was a key factor affecting soil bacterial community structure in the degraded wetland （<i>P&lt;</i>0.05）. The functional differences of bacterial communities were mainly affected by the contents of soil total iron and zinc （<i>P&lt;</i>0.05）. In conclusion, soil physical and chemical properties, bacterial community diversity and structure, and bacterial community function changed regularly with the degree of degradation. Soil pH； contents of total nitrogen, total carbon, and organic carbon； and physical characteristics of <i>Carex</i> tussock were the key factors affecting the microbial community in the degraded wetland, which can provide the scientific basis for understanding the degradation and restoration processes of <i>Carex</i> marsh ecosystems.</p>","PeriodicalId":35937,"journal":{"name":"环境科学","volume":"46 2","pages":"1203-1212"},"PeriodicalIF":0.0,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143441944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Contamination of Conjugative Antibiotic-resistant Plasmids in Large-scale Livestock and Poultry Manure and Their Occurrence Characteristics of Antibiotic Resistance Gene].","authors":"Ying Li, Lei Shen, Hao-Ze Gao, Ya-Jie Guo, Xu-Ming Wang, Guo-Zhu Zhao, Tian-Lei Qiu","doi":"10.13227/j.hjkx.202401259","DOIUrl":"https://doi.org/10.13227/j.hjkx.202401259","url":null,"abstract":"<p><p>The emergence and spread of antibiotic resistance in bacterial pathogens are now becoming a serious threat to public health globally. To study the occurrence and transfer characteristics of plasmid-mediated mobile antibiotic resistance genes （ARGs） in manure, antibiotic-resistant plasmids were captured from layers, broilers, and pig farms in Beijing, Hebei, and Ningxia provinces. The conjugative antibiotic-resistant plasmids （CARP） were captured by a filter membrane conjugation experiment, and the transfer frequency of plasmids from feces to recipient bacteria was tested. The ARGs-carried plasmid was extracted and sequenced with the Illumina sequencer, and the replicon types of CARP were identified with the PlasimidFinder database. The antibiotic-resistant phenotype of the captured conjugative plasmid was determined using the disk diffusion method （Kirby-Bauer）. In general, the 125 CARPs that were captured from 35 farms carried 13 types and 65 subtypes of ARGs. The most common ARGs were <i>floR</i>, <i>aac （6'）-lb7,</i> and <i>TEM-150</i>. Certain differences exist in the prevalence of CARP in the manure of different animals. The CARP in layer manure had a higher transfer frequency and prevalence than those in other animal farms, but the level of multidrug resistance conferred by these plasmids was lower than that of broilers and pigs. The 49 shared ARGs were observed from plasmids of broilers, layers, and pigs, of which 64% belonged to aminoglycosides, <i>β</i>-lactamase, fluoroquinolones, and trimethoprim-resistant genes. The antibiotic-resistant phenotypic characteristics of conjugants were similar with genotypes, and the dominant resistant conjugants belonged to <i>β</i>-lactamase （95.31%）, tetracyclines （89.06%）, aminoglycosides （87.5%）, and fluoroquinolones （68.75%）. IncH, IncN, and IncR plasmids were detected in pig manure, and 12.5% of the conjugants carried five or more high-risk ARGs in pig farms. The proportion of high-risk ARGs in pig farms was higher than that in other animal farms. In conclusion, the CARP in livestock manure commonly carries multiple types of ARGs, which can provide multiple antibiotic resistance capabilities for host bacteria. In addition, high-risk ARGs are carried by the broad host range of conjugative plasmids, which can promote the spread of high-risk ARGs in livestock farms to the surrounding environment.</p>","PeriodicalId":35937,"journal":{"name":"环境科学","volume":"46 2","pages":"1245-1254"},"PeriodicalIF":0.0,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143441957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Degradation Processes of Biodegradable Plastics in Soil and Their Effects on Soil Animals].","authors":"Li-Juan Zhang, Jie Chen, Rui-Xue Ao, Xiu-Lan Zhao","doi":"10.13227/j.hjkx.202401075","DOIUrl":"https://doi.org/10.13227/j.hjkx.202401075","url":null,"abstract":"<p><p>Biodegradable plastics are increasingly recognized as a viable alternative to conventional plastics, offering a potential solution to persistent plastic pollution. However, the efficiency of their biodegradation and the subsequent ecological impacts have garnered significant attention. These biodegradable plastics primarily consist of biodegradable polymers with minor quantities of additives such as plasticizers, dyes, photo-stabilizers, etc., to obtain greater performances and some specific physicochemical properties or functionalities. The degradation of biodegradable plastics in soil consists of three phases： biodeterioration, bio-depolymerization, and bioassimilation coupled with mineralization. These processes are decisively influenced by the properties of the biodegradable plastics, while they can face interference from the biotic and abiotic factors of the soils. During degradation, substantial quantities of microplastics, additives, oligomers, and monomers are released into the soils, which can easily be ingested by soil animals and consequently pose more serious negative effects on the behavior, growth, and reproduction of soil animals. Furthermore, biodegradable microplastics can act as carriers of soil pollutants such as heavy metals and organic pollutants, resulting in soil combined contaminations and inducing more serious detrimental effects on soil organisms. Finally, the prospects for further studies in this field are put forward.</p>","PeriodicalId":35937,"journal":{"name":"环境科学","volume":"46 2","pages":"1145-1154"},"PeriodicalIF":0.0,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143442022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Distribution Characteristics,Sources Analysis,and Potential Ecological Risk Assessment of Heavy Metals in Soils of Typical Hazardous Waste Incineration Disposal Sites].","authors":"Hong Tian, Fang Liu, Jie Yang","doi":"10.13227/j.hjkx.202402016","DOIUrl":"https://doi.org/10.13227/j.hjkx.202402016","url":null,"abstract":"<p><p>To explore the heavy metal pollution characteristics and ecological risk status of soil in typical hazardous waste incineration disposal sites, data was collected from 85 different depth profiles of soil samples taken from five typical hazardous waste incineration disposal sites in Shanghai. The pollution level and potential risk of six heavy metals （Hg, Cd, As, Pb, Ni, and Cu） were evaluated using the geo-accumulation index, the Nemerow comprehensive pollution index, and the potential ecological risk index, and the APCS-MLR receptor model used to analyze the pollution sources. The results showed that： ① Varying degrees of accumulation of the six heavy metals exist in the soil of the study area. Except for As, the content of other heavy metals in the surface soil exceeded the background value, and the degree of pollution decreased with increasing soil depth. The proportion of moderately accumulated sites for Cu and Cd was relatively high, and there were certain heavily polluted sites in the surface soil, which posed a high local risk. ② The results of the APCS-MLR receptor model indicated that source 1 （Cu, Pb, and Cd） was mainly affected by stockpiling and transportation, source 2 （As） was mainly affected by natural geological background, source 3 （Hg） was mainly affected by the hazardous waste incineration process, and the other source （Ni） was mainly affected by mixed sources in multiple ways. ③ The geo-accumulation index indicated that there was no pollution of the six heavy metals at different vertical depths in the study area. The Nemerow comprehensive pollution index showed that 5.88% of the surface soil samples in the study area were moderately polluted, 2.94% were severely polluted, and the remaining points were at a mild pollution level. The potential ecological risk index showed that the entire study area was at a mild pollution level, with some locations presenting strong risks. Severe local pollution may exist in concentrated areas, and the main potential risk factors were Hg and Cd.</p>","PeriodicalId":35937,"journal":{"name":"环境科学","volume":"46 2","pages":"1089-1097"},"PeriodicalIF":0.0,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143442065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Effects of Grazing Intensity on Greenhouse Gas Emissions in a Typical Grassland].","authors":"Yue-Qiang Wu, Wen-Hong Ma, Zhi-Yong Li, Le Qi","doi":"10.13227/j.hjkx.202401058","DOIUrl":"https://doi.org/10.13227/j.hjkx.202401058","url":null,"abstract":"<p><p>The research investigating the effects of different grazing intensities on greenhouse gas emissions within typical steppe ecosystems aids in formulating effective management strategies for these ecosystems. Furthermore, it plays a vital role in developing approaches to reduce greenhouse gas emissions. To investigate the effects of different grazing intensities on greenhouse gas emissions in typical steppe ecosystems, four treatments were established： no grazing （CK）, light grazing （LG）, moderate grazing, and heavy grazing （HG）. The greenhouse gas emission fluxes were measured using the static dark chamber infrared spectroscopy method. The results showed that： ① Significant seasonal changes exist in ecosystem respiration and CH₄ emission flux. Compared with the CK treatment, the HG treatment significantly reduced the total ecosystem respiration emission by 31.43%, while the total CH₄ emission was not significant among all treatments. Compared with the LG treatment, the HG treatment significantly reduced the total N₂O emission by 94.03% （<i>P</i> &lt;0.05）. ② A significant linear correlation exists between the values of ecosystem respiration pairs and soil temperature （<i>P</i> &lt;0.001）, and there was a significant linear relationship between ecosystem respiration and soil water content under the CK and HG treatments （<i>P</i> &lt;0.05）, mainly related to soil temperature. Except for the LG treatment, the CH₄ emission fluxes of the other treatments showed a quadratic correlation with soil temperature, and the CH₄ emission fluxes of all treatments were linearly correlated with soil water content and were mainly correlated with soil water content （<i>P</i> &lt;0.01）. A significant linear correlation exists between N₂O emission flux and soil temperature in the LG treatment （<i>P</i> &lt;0.05）. ③ Compared with that in CK, the HG treatment significantly decreased soil water content, soil total carbon, soil total nitrogen, vegetation aboveground biomass, and litter, and significantly increased soil temperature and soil bulk density （<i>P</i> &lt;0.05）. Heavy grazing reduced the total greenhouse gas emissions and total vegetation biomass. Although it reduced the carbon emissions of the grassland ecosystem, it was not conducive to maintaining the ecological balance of grassland. This study can provide reference data and theoretical support for evaluating the effects of grazing on the source-sink functions of grassland ecosystems.</p>","PeriodicalId":35937,"journal":{"name":"环境科学","volume":"46 2","pages":"1255-1264"},"PeriodicalIF":0.0,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143442103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Effects of Simulated Nitrogen Deposition on Soil Organic Carbon Fractions and Carbon Pool Management Indicators in Mid-subtropical <i>Eucalyptus</i> Plantations].","authors":"Xin-Yue Mao, Yu-Yi Shen, Jun-Zhi Chu, Guang-Ping Xu, Zi-Hui Wang, Yang Cao, Yun-Shuang Chen, De-Nan Zhang, Ying-Jie Sun, Ke-Chao Huang","doi":"10.13227/j.hjkx.202401166","DOIUrl":"https://doi.org/10.13227/j.hjkx.202401166","url":null,"abstract":"&lt;p&gt;&lt;p&gt;To study the characteristics of soil organic carbon （SOC） components and carbon pool management indicators of a &lt;i&gt;Eucalyptus&lt;/i&gt; plantation after continuously simulating nitrogen deposition for five years and to explore the relationship between soil organic carbon components and soil environmental factors, it is helpful to understand the influence of nitrogen deposition on soil quality and SOC pool stability and provide a scientific basis for sustainable management of subtropical forest ecosystems and protection of the soil environment. In a long-term positioning test of simulating nitrogen deposition from 2018, four different treatments were selected： CK [0 kg·（hm&lt;sup&gt;2&lt;/sup&gt;·a）&lt;sup&gt;-1&lt;/sup&gt;], low nitrogen LN [50 kg·（hm&lt;sup&gt;2&lt;/sup&gt;·a）&lt;sup&gt;-1&lt;/sup&gt;], middle nitrogen MN [100 kg·（hm&lt;sup&gt;2&lt;/sup&gt;·a）&lt;sup&gt;-1&lt;/sup&gt;], and high nitrogen HN [150 kg·（hm&lt;sup&gt;2&lt;/sup&gt;·a）&lt;sup&gt;-1&lt;/sup&gt;]. The contents of SOC, light fraction organic carbon （LFOC）, heavy fraction organic carbon （HFOC）, easily oxidized organic carbon （EOC）, dissolved organic carbon （DOC）, particulate organic carbon （POC）, microbial biomass carbon （MBC）, soil physicochemical properties, carbon cycling-related enzyme activity, and carbon pool management indicators following the different treatments were measured. The results showed that： ① Compared to those in the control, the contents of SOC, DOC, EOC, POC, and MBC increased significantly with the increase in nitrogen deposition. By contrast, HFOC tended to decrease under the higher nitrogen deposition treatment. ② The input of nitrogen improved the carbon pool activity index and carbon pool management indicators significantly with the increase in nitrogen deposition levels. Nitrogen deposition enhanced the activities of sucrase, amylase, and dehydrogenase related to carbon cycling and improved soil carbon pool quality effectively. ③ The correlation and redundancy analysis between organic carbon components and soil environmental factors showed that soil pH, organic carbon content, and activated carbon components were negatively related. Physical and chemical indicators such as TN, AN, TK, AK, exchangeable ions, etc., all showed a significant or extremely significant positive correlation with organic carbon and its components, respectively. The soil physicochemical properties and carbon cycle-related enzymes promoted the increase in soil organic carbon and its component content to a certain extent. Soil exchange hydrogen, available potassium, total potassium, and amylase were the main environmental factors driving the changes in soil organic carbon composition and carbon pool management indicators. In conclusion, the continuous simulated nitrogen deposition for five years improved soil organic carbon, active organic carbon components, and carbon pool management indicators. This was beneficial to maintaining or improving the soil fertility of &lt;i&gt;Eucalyptus&lt;/i&gt; plantations in mid-subtropical regions. However, there was a potential decrease in the","PeriodicalId":35937,"journal":{"name":"环境科学","volume":"46 2","pages":"1032-1045"},"PeriodicalIF":0.0,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143442107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Microbial Ecology in the Mask-derived Plastisphere in a Water Environment].","authors":"Si-Wei Peng, Guang-Yi Zhang, Yuan-Yuan Jiao","doi":"10.13227/j.hjkx.202402057","DOIUrl":"https://doi.org/10.13227/j.hjkx.202402057","url":null,"abstract":"<p><p>As a result of the impact of COVID-19 and other respiratory diseases, the regular use of medical masks and the associated risk that the mask waste enters the water environment have increased, and the mask-derived microplastics are finally posing a potential impact on the aquatic ecological environment. This study explored the microbial diversity, function, assembly mechanism, and ecological network in the plastisphere derived from different layers of masks. The results indicated that the plastisphere in each layer had a unique microbial community, and the community richness gradually increased over time. The functions of microbial communities in the plastisphere, including pathogenicity, phototrophy, compound degradation, and the functions related to the cycling of carbon, nitrogen, and sulfur, changed significantly over time. As to the microbial assembly mechanism in the plastisphere, stochastic processes were more dominant （NST&gt;0.5）, but the influence of deterministic processes gradually grew. The ecological network results indicated that all the plastispheres exhibited a high number of modules and high modularity, and the complexity of the microbial community gradually decreased with colonization time. This study indicates that the mask-derived plastisphere has a unique ecological process, which strengthens our understanding of the ecological effects and microbial colonization processes of the mask-derived plastisphere.</p>","PeriodicalId":35937,"journal":{"name":"环境科学","volume":"46 2","pages":"1193-1202"},"PeriodicalIF":0.0,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143442202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Occurrence Characteristics and Ecological Risk Assessment of Soil Microplastics in Xinxiang Section of Weihe River Basin].","authors":"Yan Zhang, Ming Dou, Fei-Yu Wang, Kai-Yang Li, Yu-Ze Zhou, Ping Li, Song-Ze Hao, Zhi-Jie Liang","doi":"10.13227/j.hjkx.202402034","DOIUrl":"https://doi.org/10.13227/j.hjkx.202402034","url":null,"abstract":"<p><p>To understand the occurrence characteristics of microplastics in the soil of the Xinxiang section of the Weihe River Basin, the soil samples of different soil types and different soil layers were collected, soil microplastics were identified using the Agilent 8700 laser direct infrared （LDIR） chemical imaging system, and the ecological risks of soil microplastics were assessed using the polymer risk index （<i>H</i>） and pollution load index （PLI）. The results showed that the proportions of polyurethane （PU） and polyethylene （PE） were 17.57% and 15.97%, respectively, in the soil of the Xinxiang section of Weihe River Basin； the particle diameter of microplastics mainly ranged from 20 to 100 μm, and the proportions of 20 to 50 μm and 50 to 100 μm were 76.17% and 15.56%, respectively； and the average abundance of microplastics was （4 629±683） n·kg^-1. Significant differences exist in soil microplastic type （<i>P</i>&lt;0.001） and microplastic abundance at different soil depths （<i>P</i>&lt;0.05）. The microplastic particle diameter （<i>P</i>&lt;0.05） at each sampling site and the microplastic abundance at each sampling site decreased with the increase in soil depth. The abundance of PU and PE at sampling sites S7 and S3 was 1 587 n·kg^-1 and 960 n·kg^-1, respectively. The ecological risk of soil microplastics at each sampling site decreased with the increase in soil depth； the ecological risk of soil microplastics at sampling site S7 was at high risk, sampling site S6 was at low risk, and other sampling sites were at medium risk.</p>","PeriodicalId":35937,"journal":{"name":"环境科学","volume":"46 2","pages":"1168-1180"},"PeriodicalIF":0.0,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143442219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Seasonal Pollution Characteristics and Source Apportionment of Atmospheric VOCs in Central Urban Area of Chongqing].","authors":"Jia Yao, Zhen-Liang Li, Mu-Lan Chen, Ling Li, Qin Xu, Wei-Kai Fang, Chao Peng, Chong-Zhi Zhai, Feng-Wen Wang, Pei-Li Lu","doi":"10.13227/j.hjkx.202402041","DOIUrl":"https://doi.org/10.13227/j.hjkx.202402041","url":null,"abstract":"<p><p>The long-term seasonal pollution characteristics, environmental effects, and sources of atmospheric volatile organic compounds （VOCs） were investigated based on the one-year （06/2021-05/2022） online observation data of VOCs in the central urban area of Chongqing. The results showed that during the observation period, the mean value of <i>φ</i>（VOCs） was 31.5×10^-9, of which alkane accounted for the highest proportion （39.6%）, followed by oxygenated VOCs （OVOCs） （15.6%）, halogenated hydrocarbons （13.9%）, aromatic hydrocarbons （11.6%）, olefin （10.5%）, and alkyne （8.3%）. In terms of time, the volume fraction changed to winter （35.7×10^-9） &gt; autumn （32.5×10^-9） &gt; summer （31.3×10^-9） &gt; spring （27.6×10^-9）. In summer, the highest contribution of aromatic hydrocarbons to ozone generation was observed in 1,2,4-tritylene, toluene, and <i>m</i>/<i>p</i>-xylene species with higher ozone generation potential （OFP）. In winter, the contribution of aromatic hydrocarbons to the formation potential of secondary organic aerosols （SOA） was as high as 96%, and toluene and <i>m</i>/<i>p</i>-xylene were the main contributing species to the formation potential of SOA. The main sources of VOCs in summer were motor vehicle emissions （30.9%）, industrial emissions （21.2%）, and solvent use sources （18.6%）, and the main sources in winter were motor vehicle exhaust （35.8%）, combustion sources （30.9%）, and industrial sources （20.6%）. The contribution of combustion sources to VOCs in winter （30.9%） was significantly higher than that in summer （17.4%）.</p>","PeriodicalId":35937,"journal":{"name":"环境科学","volume":"46 2","pages":"764-773"},"PeriodicalIF":0.0,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143442232","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Response Characteristics of Farmland Soil Enzyme Activity and Microbial Nutrient Restriction Under Long-term Mulching Measures in the Loess Plateau].","authors":"Wen Xu, Jia-Qi Hao, Tian-Yu Jiang, Guo-Xi Gao, Wen-Qiang Wu, Yong-Zhong Feng, Guang-Xin Ren, Xing Wang","doi":"10.13227/j.hjkx.202402067","DOIUrl":"https://doi.org/10.13227/j.hjkx.202402067","url":null,"abstract":"<p><p>To study the response characteristics of long-term mulching measures on soil enzyme activity and the limitation of microbial nutrients in the Loess Plateau Region, the study adopted a random block design and setup based on the long-term field positioning experiment conducted in 2008. Four types of inter-field management measures were established, including conventional no-mulch （NM）, straw mulch （SM）, mulch mulch （PM）, and ridge mulch （RPM）. The changes in soil nutrients and extracellular enzyme activities, their ecological stoichiometry and influencing factors under different cover measures, were investigated using a one-way analysis of variance, a stoichiometric model of soil extracellular enzymes, and redundancy analysis （RDA）. The results showed that mulching significantly affected soil basal nutrients （<i>P</i> &lt;0.05） and that the dissolubility of organic carbon, available nitrogen （AN）, and available phosphorus （AP） showed significant dynamic changes with plant growth. The extracellular enzyme activity of C, N, and P cycles showed a positive response and increased or changed by 21.03%-161.14%, 1.11%-60.68%, and 17.55%-37.66%, respectively, with the effect of SM and RPM being more significant. During long-term tillage, soil microorganisms as a whole faced C and N nutrient limitations. Under the mulching treatment, the vector angle increased significantly by 11.52%-23.17% in the early growth stage of crops, indicating that the microbial nitrogen limitation was alleviated, while the overall vector length showed an increasing trend and increased by 10.38%-84.38%. Additionally, the level of C restriction became stronger over time. The RDA analysis showed that soil water content, AN, and AP content were the key factors affecting the enzyme activity and their measurement relationship in the Loess Plateau. In summary, the implementation of SM and RPM tillage practices in the Loess Plateau Region had a stronger impact on soil nutrient properties and enzyme activities and could be combined to achieve better results. In the meantime, the appropriate application of nitrogen fertilizer should be considered to mitigate nutrient limitations. The research results can help better understand the influence of mulch on soil microbial nutrient utilization strategies in agricultural land and its regulatory mechanisms. Moreover, it provides theoretical foundations for the long-term sustainable development of the Loess Plateau hilly area.</p>","PeriodicalId":35937,"journal":{"name":"环境科学","volume":"46 2","pages":"1056-1064"},"PeriodicalIF":0.0,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143442251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}