Soil on both sides of highways is highly susceptible to contamination from traffic emissions, industrial activities, and other anthropogenic factors, leading to a gradual accumulation of heavy metals. This study analyzed total concentrations and soluble components of zinc (Zn), cadmium (Cd), chromium (Cr), and lead (Pb), along with soil physicochemical properties, in lotus fields adjacent to an expressway in northern Bengbu, China. Both Pearson and Spearman correlations were used to assess variable associations. In addition, Principal Component Analyses (PCA) were employed to elucidate synergistic regula­tion between heavy metal speciation and soil properties. The bioavailability coefficient, risk assessment code, and transfer coefficient were used to evaluate heavy-metal bioavailability and soil–plant migration. Results showed that the residual fractions of Zn, Cd, and Cr were positively correlated with their total concentrations, whereas the acid-soluble fractions showed no such correlation. Lotus seeds demonstrated the strongest transport for Zn and Cd, roots for Pb, and stems for Cr. PCA revealed that spatial differences and crop-specific migration patterns were associated with distinct environmental control structures under varying traffic pollution intensities. In high-pollution plots, Pb/Zn activity was primarily associated with electrical conductivity, whereas in low-pollution plots, both pH and electrical conductivity showed strong associations with metal distribution patterns. Unique mechanisms included the reverse effects of heavy metal input on conductivity and the insignificant regulation of soil moisture in humid habitats. Cadmium exhibited high acid-soluble proportions, strong bioavailability, and elevated plant mobility across both regions, posing the primary ecological risk. This study advances pollution assessment from bivariate correlations to multivariable mechanistic analysis, providing a systematic scientific basis for regional ecological risk prevention and agricultural product safety.

As biomass energy becomes a key part of the renewable energy mix, optimizing biomass harvesting operations is crucial for ensuring efficiency, economic viability, and a sustainable energy supply. This study analyzed two biomass harvesting operations in the Coastal Plain of Florida, each employing rubber-tired feller-bunchers, grapple skidders, trailer-mounted knuckleboom loaders, and whole-tree woodchippers. While both operations produced wood chips, Operation A harvested material from a stand dominated by small-diameter trees, whereas Operation B harvested understory and unmerchantable trees from a mixed stand where merchantable stems were handled separately. The average productivity rates per productive machine hour (PMH) were 17 green tonnes for the feller-bunchers, 38 green tonnes for the skidders, and 64 green tonnes for the chippers. Low productivity of the feller-bunchers was attributed to the small diameter of harvested trees, with over 60% having a diameter at breast height (DBH) of 7.6 cm or less. Despite chippers having a low utilization rate (58.5%), feller-buncher capacity ultimately constrained overall system productivity. Chipping was the most expensive activity at $USD 105 per scheduled machine hour (SMH), followed by felling ($USD 102), skidding ($USD 98), and loading ($USD 92). Compared with the 2020 TimberMart-South Coastal Plain final-harvest cut-and-load reference rate of $USD 12.5 per tonne, biomass cut-and-load rates were $USD 2.3 higher in Operation A and USD $5.1 per tonne higher in Operation B, with lower costs in Operation A due to higher productivity. This study provides valuable insights into improving the economic efficiency and operational productivity of biomass harvesting systems while supporting the sustainable development of biomass energy.

Urban green spaces are essential components of urban ecosystems, but they face increasingly threatened by potentially toxic elements (PTEs) such as lead (Pb), zinc (Zn), and chromium (Cr), primarily introduced through road traffic. This study examines the bioavailability and enrichment characteristics of these PTEs in six common urban greening plants (Viburnum odoratissimum, Jasminum nudiflorum, Pittosporum tobira, Aucuba japonica var. variegata, Photinia × fraseri, and Euonymus japonicus 'Aurea-marginatus') and their rhizosphere soils to understand soil–plant interactions under traffic pollution stress. Pollution risk was assessed using the Risk Assessment Code (RAC), while bioavailability was evaluated via Bioconcentration Factor (BCF). The identical-discrepant-contrary (IDC) gray relational analysis explored relationships between root PTEs and soil diethylenetriaminepentaacetic acid (DTPA)-extractable PTEs, with quadratic regression modeling soil–plant dynamics. The RAC results indicated that Pb posed a higher pollution risk than Cr and Zn. BCF analysis revealed both Pb and Zn exhibited high bioavailability in the rhizosphere soils of the studied plants. The IDC gray analysis demonstrated no significant correlation between total PTE concentrations in plant roots and DTPA-extractable PTEs in the corresponding soils, except for Pittosporum tobira. Regression analysis identified quadratic models as the best fit for describing the relationships between soil and plant PTE concentrations. Pb exhibited the highest bioavailability and pollution risk among the three PTEs studied. Cr predominantly accumulated in roots, while Pb and Zn showed species-specific accumulation in roots or leaves. Quadratic models best described the soil–root PTE relationships. These results highlight the role of species-specific accumulation and soil–plant interactions in assessing the potential of roadside plants to cope with traffic-related PTE contamination.

Road traffic is increasingly becoming the primary source of potentially toxic elements (PTEs) pollution in soil, leading to significant ecological and health risks. This study aimed to investigate the potential ecological risks posed by chromium (Cr), nickel (Ni), lead (Pb), and zinc (Zn) in roadside areas and urban parks green spaces, as well as to assess the health risk associated with PTEs in urban parks. Soil samples were collected from the G42 Nanjing Connection Line (NCL), Zhongshan Gate Street (ZGS) and three parks including Xiamafang Site Park (XSP), Yueya Lake Park (YLP) and Zhongshan Sports Park (ZSP). A portable X-ray fluorescence (PXRF) analyzer was used to determine the PTE content in 40 roadside and 149 park soil samples, followed by risk assessments using the potential ecological risk index and a health risk assessment model. The ecological risk index for PTEs in the green areas was ranked as follows: Pb > Ni > Cr > Zn. The calculated risk indices were: 15.64 (NCL), 14.71 (ZGS), 13.52 (XSP), 13.21(YLP), 11.43 (ZSP). The Hazard Index (HI) of Cr in the parks were recorded at 0.98 (YLP), 0.83 (XSP), and 0.94 (ZSP), indicating values close to 1. Cr posed a higher potential non-carcinogenic risk compared to the other elements, primarily through oral ingestion (60.65%). This study provides a foundational basis for assessing and controlling the PTEs in roadside and urban park green spaces.

In addition to industrial contamination sources, road traffic sources are becoming major sources of potentially toxic elements (PTEs) contamination in soil. The PTEs contaminants generated during transport mainly include lead (Pb) and other elements. In this study, to clarify the sources of Pb in the roadside atmosphere and soil and their relative contributions, roadside atmospheric dustfall, sediment and soil samples were collected in industrial and nonindustrial areas, and the Pb isotope values of the samples were determined via inductively coupled plasmamass spectrometry (ICPMS). The sources of Pb in the roadside atmosphere and soil samples were quantified via isotope tracing. The results revealed that vehicle emissions contributed the most to Pb in the roadside atmosphere, followed by road sediment and natural atmospheric dustfall, with contributions ranging from 43.5 % to 48.9 %, 35.3-39.8 %, and 15.8-16.7 %, respectively. Roadside atmospheric dustfall contributed the most to Pb in roadside soil, followed by road sediment. Among these sources, roadside atmospheric dustfall and road sediment contributed 68.3-68.4 % and 31.6-31.7 %, respectively, in nonindustrial areas and 61.2-61.3 % and 38.7-38.8 %, respectively, in industrial areas. The results of this study provide a basis for preventing and controlling Pb pollution in roadside soils.

为深入贯彻党和国家的教育方针,应坚持以人为本的教育理念,在知识传授的过程中培养学生的职业理想信念和社会责任感,培育大学生的实践能力与创新精神.文章作者以"公路工程定额与概预算"课程为研究对象,分析"公路工程定额与概预算"课程教学目标,提出了"公路工程定额与概预算"的课程思政教育目标和整体建设思路,通过挖掘"公路工程定额与概预算"课程的思政元素,结合高校大学生的学习现状,提出与学生学习能力相适应的教学方法,将专业教学内容与思政元素融合,发挥专业课程的育人功能.

在工业化时代,重金属污染愈加严重,国内外对此问题也愈加重视.大气环境中,重金属极易附着于大气颗粒物,并随着颗粒物进入人体,对人体健康造成危害.本文论述了大气颗粒物中重金属检测的预处理方法和主要检测技术.通过对大气颗粒物重金属的国家环境监测方法标准进行分析发现,在精密度和准确度方面,电感耦合等离子体质谱法更占优势;从检测过程方面看,X射线荧光光谱法的样品预处理等更为便利;同时X射线荧光光谱法和电感耦合等离子体原子发射光谱法所需费用相对较高.

炉渣作为生活垃圾焚烧过程的主要副产物之一,其不仅具有可与道路工程常用天然石料媲美的工程特性,而且具备胶凝材料的水化特性,在道路工程材料与固废资源化领域受到高度关注,并且已逐渐发展成为一种新兴的绿色建筑材料.综述了炉渣的微观形貌与结构、浸出特性及基本性质,表明炉渣作为路面集料的可行性,提出了当前炉渣集料实现大规模应用面临的问题.

Heavy metals content in tires affects the safety of soil and agricultural products. The digestion method is a pretreatment for determining heavy metals in tire samples, and will affect the efficiency and accuracy of the heavy metal determination. The microwave digestion process and reagents for tire samples are not currently standardized. Therefore, this study attempts to provide an appropriate method of resolution for scholars. All digestion processes were performed in Mars One. We tested 15 different acid mixtures to determine the best reagent type and dose and then investigated the effect of maximum temperature, holding time, and sample grams on the degree of digestion. In summary, the best condition to digest the tire sample was a mixture of 3 ml HNO 3 and 7 ml H 2 SO 4 , taking 0.1 (± 0.0005) g tire sample, at the maximum digestion temperature of 220 °C for 25 min. The experimental conclusion will provide a reliable experimental method for scientists using MARS One to study heavy metals in tires. At the same time, researchers using the MARS series can also find valuable references in this paper.

Abstract With the accelerated pace of road construction, road traffic sources are becoming one of the main sources of environmental heavy metals pollutants in addition to industrial pollution sources. Studies have shown that the heavy metals pollutants generated during transportation mainly include lead (Pb) and other elements. Most studies have focused on the characteristics and distribution patterns and qualitative source analysis of heavy metals pollution in roadside soils. However, systematic quantitative analysis of heavy metals in roadside soils and the atmosphere has not yet been achieved, which makes it difficult to effectively support the prevention and management of heavy metals pollution in roadside soils. Therefore, in this study, to clarify the sources of Pb in the roadside atmosphere and soils and their relative contributions, roadside atmospheric dustfall, sediment and soil samples were collected in industrial and nonindustrial areas, and the Pb isotopic values of the samples were determined via inductively coupled plasma–mass spectrometry (ICP‒MS). The sources of Pb in the roadside atmosphere and soil samples were quantified by isotope tracing. The results showed that vehicle emissions contributed the most to Pb in the roadside atmosphere, followed by road sediment and natural atmospheric dustfall, with contributions of 43%-49%, 35%-40% and 15%-17%, respectively. Roadside atmospheric dustfall contributed the most to Pb in roadside soil, followed by road sediment, with contributions of 68%-69% and 31%-32%, respectively, in nonindustrial areas and 61%-62% and 38%-39%, respectively, in industrial areas. The study results provide a basis for the prevention and control of Pb pollution in roadside soils.

高校课程思政建设是落实立德树人的重要举措.为了提高森林工程专业学生的思想政治素养,根据本专业人才培养方案,制定"森林工程导论"课程目标和思政育人目标.从专业的发展历程、人才培养目标、杰出校友事迹、社会热点事件和典型案例等方面深挖课程思政元素,进行课程思政元素与教学内容有机融合的教学设计,采用案例式、讨论式、问题导向式和启发式等教学方法和手段,并应用到森林工程导论课程的教学实践中,效果较显著.

We examined the topsoil heavy metal concentration of four different urban functional areas (UFAs) in Nanjing, China: a heavy traffic area (HA), an industrial area (IA), a leisure area (LA), and a farmland area (FA). The purpose of the study is as follows: (i) to determine which heavy metal(s) were the primary pollutant(s) in the study area and the contamination status of five heavy metals (Cr, Ni, Cu, Zn and Pb) in the urban topsoil of Nanjing city, (ii) to assess the comprehensive pollution risk of heavy metals in UFAs using two methods: the ecological risk index and the fuzzy comprehensive evaluation based on Analytical Hierarchy Process (AHP). X-ray fluorescence (PXRF) was used to measure the soil heavy metal content, the potential ecological risk method was implemented to evaluate the risk level of each UFA, and the fuzzy comprehensive evaluation method was applied to assess the pollution degree of heavy metals in UFAs. PXRF analysis showed that Cr was the primary metal pollutant in the study area. There were also significant enrichments of Cu, Zn and Pb in collected soil samples. The four UFAs were ranked IA > HA > LA > FA in terms of the potential heavy metal ecological risk; the distribution pattern determined by the fuzzy comprehensive evaluation model followed the same order. Overall, 84.70%, 12.98% and 2.32% of the 647 sites were classified as class I (clean), class II (lightly polluted), and class III (heavily polluted), respectively, suggesting that most soil in Nanjing was clean. Based on the calculated weight matrices of the potential ecological risk results, the major pollutants were Cr and Zn. This investigation highlighted that most of the soil in the study area is clean, but certain sites are polluted to some degree, especially in the IA. The study area showed an overall moderate ecological risk for heavy metal pollutants, with Cu and Pb posing the greatest risk.

介绍了路域环境中土壤重金属污染来源及其扩散途径、源解析方法、土壤重金属空间异质性规律等方面的研究进展,重点总结了赋存形态及其生物有效性的方法.最后,对路域环境中土壤重金属污染研究进行总结及建议,以期为科学制定路域环境土壤污染风险管控策略及污染防治措施提供参考依据.

综述了重金属污染物源解析方法,并对其优缺点进行了阐述、对比;其次,以铅(Pb)、镉(Cd)及锌(Zn)同位素示踪为例,对其同位素的表达、测定及应用进行了分析总结;最后,针对同位素示踪法在国内外重金属污染源解析中存在的不足,对同位素源解析的研究方向作了一些粗浅的展望,以起抛砖引玉之用.

目前国内高校教学质量评价多针对教师,这种评价方式无法全面、客观地掌握学生的学习成效.文章基于OBE理念,研究构建高校教学质量管理体系的有效路径.通过建立完善的教学组织机构,构建校、院、系三级教学过程质量监控机制;建立以学生为主体的综合评价体系,定期对教学质量进行全面检查和客观评价;同时不断推进教学改革,注重过程性考核与管理;鼓励教学创新,加大学习挑战度,这些改革构想和措施能够提升学生自主学习能力,确保培养目标实现.

课程是人才培养的核心要素,课程问题也是教育最微观问题,但解决的是教育最根本问题.2018年教育部第一次提出了"金课"的概念,指出合理增加课程难度、拓展课程深度、扩大课程的可选择性,打造具有深度、难度和挑战度的"金课".本文以"建设项目环境影响评价"课程教学改革为例,基于"雨课程"教学辅助软件,以学生为中心的教学理念,通过分析学情,因材施教、翻转课堂、小组讨论等方式激发学生的学习兴趣,实现课程的创新性;与企业协同育人,加强学生的实践创新能力;以非标准化考核方式,调动学生学习的主动性和探索发现的积极性,提高课程学习的挑战度;课程实践结果表明:教师的教学科研能力和学生学习的效果都有了较大地提高.

为分析不同土壤重金属污染评价方法的适用性,以南京市不同功能区表层土壤为研究对象,通过PXRF法测定重金属Cr、As、Ni、Pb、Zn、Cu在不同功能区土壤中的含量.利用单项污染指数法、地质累积指数法、内梅罗综合指数法、污染负荷指数法和潜在生态危害指数法对其污染水平评估.结果表明:单项污染指数法和地质累积指数法的评价结论完全一致,其污染程度为Cr>Pb>Zn>Cu>Ni>As.污染负荷综合指数法与潜在生态危害指数法的评价结果基本一致,由大到小顺序为:工业区、休闲区、交通繁忙区、农田区.内梅罗综合指数法与潜在生态危害指数法对各个功能区综合评价结果也基本一致,分别为轻微污染和存在轻度生态风险.

不同品种的杨树对重金属污染土壤的修复和耐受性存在显著差异,为了解不同品种的杨树对铅(Pb)和镉(Cd)的耐抗特性,以南林95杨和南林895杨为研究对象,研究其在不同浓度Pb胁迫和Pb-Cd复合胁迫下的生理响应,对其根系活力、过氧化氢酶(CAT)活性、可溶性蛋白质和叶绿素含量等指标进行对比分析,并采用主成分分析和隶属函数法综合评价2种杨树对Pb和Cd胁迫的耐受性.结果表明,南林95杨和南林895杨在Pb胁迫和Pb-Cd复合胁迫下,各生理指标的变化趋势大致相同,均表现出较强的耐受性;在Pb胁迫和Pb-Cd复合胁迫下,南林895杨的根系活力和CAT活性均强于南林95杨,但其叶绿素含量少于南林95杨.Pb胁迫下,南林95杨的可溶性蛋白质含量略高于南林895杨,在Pb-Cd复合胁迫下则相反.综合评价结果表明,南林895杨对重金属Pb和Cd的耐受性强于南林95杨,具有更好的修复前景.

Background: Forest ecosystems play a crucial role in global carbon cycle. Identifying bio- or abio- drivers on forest biomass allocation pattern could improve our understanding in forest carbon sink, stock and cycle across various spatio-temporal scales. Through compiling a dataset (n=1931) of the root-shoot ratio from previous studies, here we implemented the Random Forest algorithm (RF) to elucidate main driven factors on the root-shoot ratio across China forest ecosystems. Results: (1) Forest age and forest density were both contributed mostly to root-shoot ratio variations regardless of forest origins (natural or planted forests). The relative important values (% increase in MSE) for forest density and forest age on the root-shoot ratio were 54.42% and 51.05% in the natural forests, and 74.61% and 117.27% in the planted forests, respectively; (2) Compared to soil variables (soil texture and nutrient status), climatic variables (temperature and precipitation) showed stronger effects on the root-shoot ratio; (3) Partial dependent analysis further demonstrated that root-shoot ratio initially decreased with forest age, but afterwards increased to a relative stable level (the turning point, e.g., ca. 150 yr for natural forests and ca.30 yr for planted forests); (4)The root-shoot ratio increased nonlinearly with an increase of forest density in both forest types. Forest density and precipitation seasonality exerted positively direct effects, while forest age together with temperature seasonality, mean temperature of wettest quarter and precipitation of warmest quarter had negatively effects on the root-shoot ratio of two forest types. Conclusions: The forest age, forest density and climate seasonality contributed mostly to variations of root-shoot ratios in China forest ecosystems. These results would improve our understanding of environmental drivers on forest biomass allocation over a large spatial scale, and to some extent provide a generally practical significance in forest management (e.g., time for timber harvest), although species-specific root-shoot ratio associated with ontogeny should be further investigated in the future.

Externally environmental stresses (e.g., low light environment and nutrient shortage) could limit plant growth and recruitment, even causing a species to be rare or endangered. In the present study, we aimed to elucidate whether shading environment formed in the natural forests limited growth of an endangered cypress species, Thuja sutchuenensis, by artificial shading level associated with nitrogen treatment, by compared with a widely distributed species from the same family, Platycladus orientalis. Our results showed that though leaf non-structural carbohydrates decreased with increasing shading level, T.sutchuenensis kept stable or even slight increasing relative growth rate toward lower light environments, which was opposite to the shade-intolerant species, P. orientalis. Our results did not provide evidence for a congruent suite of traits associated with rarity in T.sutchuenensis, but proved it as a shade-tolerant species and had to some extent practical significance for resource management for the targeted species.