分类： 环境科学技术及资源科学技术 >> 环境学 分类： 计算机科学 >> 计算机科学技术其他学科 提交时间： 2024-01-07
摘要： 目的 本研究的目标是开发一种便携式气相色谱仪，结合机器学习实现现场的VOC采集和快速的气味评价。 方法 我们使用卷积神经网络-长短期记忆（CNN-LSTM）建立了气味强度的预测模型。由于收集的数据量较小，我们使用生成对抗网络（GAN）对每个气味强度类别的VOC数据进行了生成，以增强模型的训练。 结果 在生成数据后，我们再次使用CNN-LSTM建立了模型，并与人工神经网络（ANN）、支持向量机（SVM）和梯度提升决策树（XG-Boost）进行了比较。结果表明，使用GAN生成数据后的测试准确率优于原始数据。 局限 未来的工作将集中在进一步优化模型和扩大数据集上，以提高预测的准确性和稳定性。 结论 这项研究表明，通过使用深度学习和生成对抗网络，我们可以有效地预测车内的气味强度，从而改善车内的空气质量。此外，我们还将探索将这种方法应用于其他环境条件下的空气质量预测。这为未来的空气质量监测和改善提供了新的可能性。由于我们的设备是便携式的，且模型结构较小可以直接嵌入到设备上，从而实现现场的VOC采集和快速的气味评价。这为未来的空气质量监测和改善提供了新的可能性。
分类： 环境科学技术及资源科学技术 >> 环境科学技术基础学科 提交时间： 2023-12-20 合作期刊: 《干旱区科学》
摘要： Globally, groundwater contamination by nitrate is one of the most widespread environmental problems, particularly in arid and semiarid areas, which are characterized by low amounts of rainfall and groundwater recharge. The stable isotope composition of groundwater (2H-H2O and 18O-H2O) and dissolved nitrate (15N-NO3 and 18O-NO3) and factor analysis (FA) were applied to explore groundwater provenance, pollution, and chemistry evolution in the northwestern part of the Amman-Al Zarqa Basin, Jordan. In this study, we collected 23 samples from the Lower Ajloun aquifer in 2021, including 1 sample from a groundwater well and 22 samples from springs. These samples were tested for electrical conductivity, total dissolved solids, pH, temperature, dissolved oxygen, the concentration of major ions (Ca2+, Mg2+, Na+, K+, HCO3, Cl, SO42, and NO3), and the stable isotope composition of groundwater and dissolved nitrate. The results revealed that groundwater in the study area is mainly CaMgHCO3 type and can be classified as fresh water, hard water, and very hard water. The range and average concentration of NO3 were 3.5230.8 and 50.9 mg/L, respectively. Approximately 33% of the sampling points showed NO3 levels above the maximum allowable concentration of 50.0 mg/L set by the World Health Organization (WHO) guidelines for drinking water quality. The values of 18O-H2O and 2H-H2O showed that groundwater in the study area is part of the current water cycle, originating in the Mediterranean Sea, with significant evaporation, orographic, and amount effects. The values of the stable isotope composition of NO3 corresponded to 15N-NO3 and 18O-NO3 values produced by the nitrification process of manure or septic waste and soil NH4+. The FA performed on the hydrochemical parameters and isotope data resulted in three main factors, with Factor 1, Factor 2, and Factor 3, accounting for 50%, 21%, and 11% of the total variance, respectively. Factor 1 was considered human-induced factor, named pollution factor, whereas Factor 2, named conservative fingerprint factor, and Factor 3, named hardness factor, were considered natural factors. This study will help local researchers manage groundwater sustainably in the study area and other similar arid and semiarid areas in the world.
分类： 环境科学技术及资源科学技术 >> 环境科学技术基础学科 提交时间： 2023-11-13 合作期刊: 《干旱区科学》
摘要： Global ecosystems and public health have been greatly impacted by the accumulation of heavy metal(loid)s in water. Source-specific risk apportionment is needed to prevent and manage potential groundwater contamination with heavy metal(loid)s. The heavy metal(loid)s contamination status, water quality, ecological risk, and health risk apportionment of the Shule River Basin groundwater are poorly understood. Therefore, field sampling was performed to explore the water quality and risk of heavy metal(loid)s in the groundwater of the Shule River Basin in northwestern China. A total of 96 samples were collected from the study area to acquire data for water quality and heavy metal(loid)s risk. There was noticeable accumulation of ferrum in the groundwater of the Shule River Basin. The levels of pollution were considered to be moderately low, as evaluated by the degree of contamination, heavy metal evaluation index, heavy metal pollution index, and Nemerow pollution index. The ecological risks were also low. However, an assessment of the water quality index revealed that only 58.34% of the groundwater samples had good water quality. The absolute principal component scores-multiple linear regression model was more suited for this study area than the positive matrix factorization model. There were no obvious noncarcinogenic or carcinogenic concerns for all types of receptors according to the values of the total hazard index and total carcinogenic risk. The human activities and the initial geological environment factor (65.85%) was the major source of noncarcinogenic risk (residential children: 87.56%; residential adults: 87.52%; recreational children: 86.77%; and recreational adults: 85.42%), while the industrial activity factor (16.36%) was the major source of carcinogenic risk (residential receptors: 87.96%; and recreational receptors: 68.73%). These findings provide fundamental and crucial information for reducing the health issues caused by heavy metal(loid)s contamination of groundwater in arid areas.
分类： 环境科学技术及资源科学技术 >> 环境科学技术基础学科 提交时间： 2023-10-17 合作期刊: 《干旱区科学》
摘要： Determining the distributions and sources of heavy metals in soils and assessing ecological risks are fundamental tasks in the control and management of pollution in mining areas. In this study, we selected 244 sampling sites around a typical lead (Pb) and zinc (Zn) mining area in eastern Inner Mongolia Autonomous Region of China and measured the content of six heavy metals, including cuprum (Cu), Zn, Pb, arsenic (As), cadmium (Cd), and chromium (Cr). The ecological risk of heavy metals was comprehensively evaluated using the Geo-accumulation index, Nemerow general pollution index, and potential ecological risk index. The heavy metals were traced using correlation analysis and principal component analysis. The results showed that the highest content of heavy metals was found in 05 cm soil layer in the study area. The average content of Zn, As, Pb, Cu, Cr, and Cd was 670, 424, 235, 162, 94, and 4 mg/kg, respectively, all exceeding the risk screening value of agricultural soil in China. The areas with high content of soil heavy metals were mainly distributed near the tailings pond. The study area was affected by a combination of multiple heavy metals, with Cd and As reaching severe pollution levels. The three pathways of exposure for carcinogenic and noncarcinogenic risks were ranked as inhalation>oral ingestion>dermal absorption. The heavy metals in the study area posed certain hazards to human health. Specifically, oral ingestion of these heavy metals carried carcinogenic risks for both children and adults, as well as noncarcinogenic risks for children. There were differences in the sources of different heavy metals. The tailings pond had a large impact on the accumulation of Cd, Zn, and Pb. The source of Cr was the soil parent material, the source of As was mainly the soil matrix, and the source of Cu was mainly the nearby Cu ore. The purpose of this study is to more accurately understand the extent, scope, and source of heavy metals pollution near a typical mining area, providing effective help to solve the problem of heavy metals pollution.
分类： 测绘科学技术 >> 摄影测量与遥感技术 分类： 环境科学技术及资源科学技术 >> 环境科学技术及资源科学技术其他学科 提交时间： 2023-10-14
摘要： 福建省作为我国首个生态文明试验区，该省生态环境质量处于优良水平，生态环境相关各项指数持续保持全国前列。为了探究近十五年福建省生态优良的成因，本文选取2005年至2020年福建全省范围的MODIS影像、土地利用数据和省市统计年鉴数据为数据源，以遥感生态指数（即RSEI）评价福建省生态系统健康程度，同时构建福建省的土地利用强度体系，并利用耦合协调模型分析RSEI与土地利用强度的耦合关系，最后对福建省2005年至2020年的生态健康进行时空演化分析。结果表明，20052020年间，福建全省的土地利用强度与生态系统健康程度之间的耦合协调度呈持续上升的态势，尤其以宁德市上升最为显著，由原来的0.0993增至0.963，其空间分布格局分布为东南沿海地区低于西北内陆地区，西南部地区高于西北部地区，东北部地区高于东南部地区。在作用类型上，福建省多数城市在2005年的土地利用强度对生态系统健康程度起到明显的阻滞作用，但随着时间的变化，城市土地利用不断优化，与生态环境质量达到中等协调，乃至优质协调，但厦门市发展相对缓慢，其2020年耦合度值为0.315，仍处于轻度失调。本研究填补了生态系统健康程度与土地利用强度互动研究机制的空白，也为福建省乃至全国的生态文明建设和生态系统健康程度评估研究提供了新的视角。
分类： 环境科学技术及资源科学技术 >> 环境科学技术及资源科学技术其他学科 分类： 计算机科学 >> 计算机应用技术 提交时间： 2023-09-22
摘要： 目的 及时和准确的空气质量预测数据对于环境管理至关重要，尤其是在空气重污染期间，预测数据可以为政府生态环境管理部门应对污染状况、精准地调配社会资源的决策提供数据支撑。方法 笔者研发的基于深度学习的空气质量预测模型AirNet6，可以兼顾准确性和实时性，实现臭氧、二氧化硫、一氧化碳等因子的7天甚至更长时间的空气质量预测。结果 与传统的化学模型演算不同，本模型使用时空图卷积网络（STGCN），能捕获历史监测数据、天气预测数据、社会活动等数据的规律，在2分钟内完成一百多个点位未来168小时数据的预测。结论 实验表明，AirNet6模型在速度、节能和准确度上，比传统的化学模型及时间序列AI模型均有明显进步。关键词：空气质量预测、人工智能、深度学习模型、时空图卷积网络
分类： 环境科学技术及资源科学技术 >> 环境科学技术基础学科 提交时间： 2023-08-23 合作期刊: 《中国科学院院刊》
摘要： 城市空间结构是城市可持续发展治理及规划的重要抓手。如何科学认识新时期城市空间结构是深化城 市认知并进行人与自然和谐调控的基础。文章简要回顾传统城市空间结构理论的时代背景，通过对新时期技 术革命、政策和社会经济环境的分析，指出城市空间结构在组织原则、组织方式、优化目标及要素成分方面 的变革性转向，阐明传统理论用于解释新时代城市治理的局限性。提出从人地地域系统理论出发重构城市空 间结构研究范式、重新认识城市空间结构载体空间、强化城市空间结构关系解析，以及革新城市空间结构测 度体系等新时代认识路径。未来应对城市空间结构认知方面挑战的关键举措，即重构城市空间结构理论、集 成城市空间结构解析关键技术、融合应用多源数据、建设城市空间结构优化调控的数字孪生平台。
分类： 环境科学技术及资源科学技术 >> 环境科学技术基础学科 提交时间： 2023-08-23 合作期刊: 《中国科学院院刊》
摘要： 矿产资源是经济社会发展的重要物质基础，不合理开采、利用、消费不仅会影响产业链和供应链的安 全，而且会对生态环境造成严重污染。新一轮科技革命和碳中和战略正在重塑全球创新版图和技术格局，伴 随着我国经济社会发展进入后疫情阶段，战略性金属的供需结构正发生深刻变化。一方面，其产业链和供应 链面临的安全挑战从传统的资源产品获取能否得到保障，蔓延至开采、加工、应用、循环利用等全产业链 条。另一方面，我国固体废物产生量迅速增长，但其作为二次金属的循环利用率仍然不高，这将导致大量资 源损失。面向未来，国家（政府） 应尽快建立二次金属的资源量和储量精细分类分级管理体系，健全二次金 属的收集和资源化体系，促进制订资源高效利用制度及标准，保障国内战略性金属的高效内循环及自给自 足，彻底摆脱战略性金属受制于人的局面。
分类： 环境科学技术及资源科学技术 >> 环境科学技术基础学科 提交时间： 2023-08-07
摘要： 有机碳埋藏作用是碳循环过程的重要环节，但迄今关于珊瑚礁沉积物中有机碳的研究却很少，影响着对珊瑚礁碳循环的准确评估。本文以南海西沙群岛永乐环礁礁外坡的现代表层沉积物为材料，分析了其总有机碳(total organic carbon, TOC)含量、总氮(total nitrogen, TN)含量、有机碳同位素(13C)值以及沉积物粒度、叶绿素含量等指标。永乐环礁礁外坡的生态状况相对较好，具有代表健康珊瑚礁生态系统沉积物中有机碳特征的潜力。结果表明：1）永乐环礁礁外坡沉积物中的TOC含量在0.71~1.66mgg-1之间，平均为1.230.31mgg-1；TN含量在0.12~0.28mgg-1之间，平均为0.200.05mgg-1。2）C/N比值在6.16~7.59之间，平均为6.750.34；13C值在-17.49~-15.85之间，平均为-16.610.49，表明沉积物中的有机碳以海洋自生来源为主，且主要来自底栖植物。3）有机碳含量与水深负相关，与叶绿素a含量和脱镁叶绿素含量正相关，表明底栖植物控制的初级生产力是礁外坡有机碳含量的主要来源。结合该区表层沉积物近3500年的平均沉积速率(1.27mma-1)，推测永乐环礁礁外坡有机碳埋藏通量介于1.12~2.61gm-2a-1之间，平均为1.930.49gm-2a-1。本研究为评估南海珊瑚礁对碳循环的贡献提供了新的信息。
分类： 环境科学技术及资源科学技术 >> 环境科学技术基础学科 提交时间： 2023-08-05
摘要： 快速预测和评估海啸是预防海洋灾害工作中的重要部分，对于海洋工程和人民生命财产安全具有重要意义。本文以一维卷积神经网络(1-Dimensional Convolutional Neural Network, CONV1D)为基础,构建岛礁地形的类海啸波水动力特性演变模型。通过输入类海啸波波高时程曲线的观测值，得到岛礁指定地点的水位淹没时程曲线，实现时间序列到时间序列的预测，达到预防海洋灾害的目的。结果显示，对类海啸波到达时间预测的平均误差为0.71%，最大水位高度预测的平均误差为6.99%，CONV1D得到的岛礁地形类海啸波水动力特性与数值结果吻合较好。
分类： 环境科学技术及资源科学技术 >> 环境学 提交时间： 2023-02-15 合作期刊: 《干旱区科学》
摘要： Water risk early warning systems based on the water environmental carrying capacity (WECC) are powerful and effective tools to guarantee the sustainability of rivers. Existing work on the early warning of WECC has mainly concerned the comprehensive evaluation of the status quo and lacked a quantitative prejudgement and warning of future overload. In addition, existing quantitative methods for short-term early warning have rarely focused on the integrated change trends of the early warning indicators. Given the periodicity of the socioeconomic system, however, the water environmental system also follows a trend of cyclical fluctuations. Thus, it is meaningful to monitor and use this periodicity for the early warning of the WECC. In this study, we first adopted and improved the prosperity index method to develop an integrated water risk early warning framework. We also constructed a forecast model to qualitatively and quantitatively prejudge and warn about the development trends of the water environmental system. We selected the North Canal Basin (an essential connection among the Beijing- Tianjin-Hebei region) in China as a case study and predicted the WECC in 25 water environmental management units of the basin in 20182023. We found that the analysis of the prosperity index was helpful in predicting the WECC, to some extent. The result demonstrated that the early warning system provided reliable prediction (root mean square error of 0.0651 and mean absolute error of 0.1418), and the calculation results of the comprehensive early warning index (CEWI) conformed to the actual situation and related research in the river basin. From 2008 to 2023, the WECC of most water environmental management units in the basin had improved but with some spatial differences: the CEWI was generally poor in areas with many human disturbances, while it was relatively good in the upstream regions with higher forest and grass covers as well as in the downstream areas with larger water volume. Finally, through a sensitivity analysis of the indicators, we proposed specific management measures for the sustainability of the water environmental system in the North Canal Basin. Overall, the integrated water risk early warning framework could provide an appropriate method for the water environmental administration department to predict the WECC of the basin in the future. This framework could also assist in implementing corresponding management measures in advance, especially for the performance evaluation and the arrangement of key short-term tasks in the River Chief System in China.
分类： 环境科学技术及资源科学技术 >> 环境工程学 提交时间： 2023-01-11
摘要： 在生态文明建设背景下，落实习近平总书记绿水青山就是金山银山理念，探索基于生态银行模式下的生态资源价值的实现对乡村振兴事业的发展至关重要。本文对已有生态资源价值转化模式和实践，即生态资产产权交易模式、生态产业实践模式、多元化产品价值实现模式、生态补偿实践模式进行梳理，分析归纳四种模式存在的政府资金缺口大、金融属性不强和投资经营积极性不高的问题。在此基础上，设计出新时期创新性生态银行模式下的生态资源价值转化新路径。该模式可以带动生态资源价值转化及乡村振兴事业的发展，为乡村地区带来生态效益和经济效益。
分类： 环境科学技术及资源科学技术 >> 环境科学技术基础学科 提交时间： 2022-12-12 合作期刊: 《干旱区科学》
摘要： Atmospheric particle pollution is one of the major factors leading to degradation of ancient wall paintings, particularly heritage sites in arid and semi-arid regions. However, current systematic research on the changes, sources, and influential factors of atmospheric particulate matter and its water-soluble ion concentrations is not sufficient. Thus, the major water-soluble ion concentrations, sources, and influential factors of atmospheric particles PM2.5 and PM10 (particulate matter with an aerodynamic equivalent diameter ≤2.5 and 10.0 μm, respectively, in ambient air) were collected from Cave 16 and its ambient exterior environment in the Dunhuang Mogao Grottoes, China, between April 2015 and March 2016. Results showed that the concentrations of PM2.5 and PM10 inside and outside the cave were the highest in March 2016 and the lowest in December 2015. The higher particle concentration from March to May was related to the frequent occurrence of sand and dust events, and the lower particle concentration from June to September was associated with good diffusion conditions, increased precipitation, and an established cave shelterbelt. The concentration of particulate matter inside the cave was affected by the concentration of particles in the air outside the cave. Ca2+, NH+ 4, Na+, Cl–, and SO2– 4were the main components of the total ions of PM2.5 and PM10 both inside and outside the cave. The total ions inside the cave were frequently affected by the disturbance of tourists' activities during the peak tourist season from May to August. Under the influence of dust, the total concentrations of Cl–, SO2– 4, Na+, NH+ 4, and Ca2+ in particles of different sizes inside and outside the cave increased, and the concentrations of Cl–, SO2– 4, Na+, and Ca2+ decreased during precipitation period. Backward air mass trajectory analysis suggested that the pollutants were mainly from Xinjiang, China. The pollutant sources of air particulates are straw burning, secondary pollution sources, soil dust, dry spring rivers, and tourist activities.
分类： 环境科学技术及资源科学技术 >> 环境科学技术基础学科 提交时间： 2022-11-12 合作期刊: 《干旱区科学》
摘要：Information on rare earth elements (REEs) in soils and plants of the Qinghai-Tibet Plateau is very limited. Therefore, in this study, we performed field sampling to explore the geochemical signatures and human health risk of REEs in soils and plants of the northeastern Qinghai-Tibet Plateau, China. A total of 127 soil samples and 127 plant samples were collected from the northeastern Qinghai-Tibet Plateau to acquire the geochemical signatures and related human health risks of REEs. The mean total concentrations of REEs in soils and plants of the study area reached 178.55 and 10.06 mg/kg, respectively. The light REEs in soils and plants accounted for 76% and 77% of the total REEs, respectively. REEs showed significantly homogenous distribution in soils but inhomogeneous distribution in plants of the study area. Characteristic parameters indicated that light REEs were enriched and fractionated significantly, while heavy REEs were moderately fractionated in soils and plants. REEs in soils and plants showed significantly negative Europium anomaly. Cerium showed slightly positive anomaly in plants and slight anomaly in soils. The normalized distribution patterns of REEs were generally similar in the analyzed soils and the corresponding plants of the study area. The average bio-concentration factor of REEs ranged from 0.0478 (Scandium) to 0.0604 (Europium), confirming a small accumulation of REEs by plants. Health risks caused by REEs in soils and plants were negligible, while risks for adults were lower than those for children. This study provides important information on REEs in soils and plants of the northeastern Qinghai-Tibet Plateau.
分类： 环境科学技术及资源科学技术 >> 环境科学技术基础学科 提交时间： 2022-11-08 合作期刊: 《干旱区科学》
摘要：The desert in northern China is one of important sources of loess and one significant source of material for sandstorms in Asia. The sand/dust that is transported from desert when sandstorms occur can destroy the growth of crops, cause serious losses and great harm to the economic construction and life safety, and cause natural environment pollution. Hence, it is very important to deepen the research into heavy metals in surface deposits at vulnerable ecological region of arid land of northern China to guide local industrial and agricultural development and improve environmental protection. In this research, 10 heavy metal elements (Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb, and Th) were tested and analyzed in 33 soil sample sites collected from the hinterland of the Tengger Desert, northern China. The results showed that the average abundance of Th exceeded its background soil value of China by more than 5.2 times, which suggests that the Tengger Desert is polluted by Th. In addition, based on principal component analysis, spatial differentiation, and correlation analysis, we identified the source of element with a coefficient of variation in abundance of greater than 0.5 or exceeding the background soil value of China. Principal component analysis and correlation analysis showed that the sources of heavy metals of Cr, Mn, Fe, Co, Ni, Cu, and Cd were similar, while those of Th and Zn were different. Moreover, based on the contents and spatial distribution characteristics of those heavy metal elements, we found that the formation of heavy metal elements enrichment areas is caused by industrial pollution, development of irrigated agricultural, geological, and geomorphic conditions, and the sedimentary environment in the study area. Our result can provide information on the environmental background values of soils in the hinterland of the Tengger Desert.
分类： 环境科学技术及资源科学技术 >> 环境科学技术基础学科 提交时间： 2022-11-08 合作期刊: 《干旱区科学》
摘要：
Many arid areas have very severe climates with extremely high summer temperatures, strong solar radiation, and a lack of drinking water during the driest season. Therefore, antelopes living in arid areas are forced to solve two main problems: avoiding overheating and maintaining water balance. Generally, there are physiological, morphological, and behavioral mechanisms for antelope adaptations to arid environments. Among the mechanisms, behavioral adjustments have a minimal cost and are activated first, while physiological mechanisms are the most energetically costly and involve adaptations to high temperatures when other mechanisms are insufficient. In previous publications, some examples of the antelope behavioral adaptations have been described only rarely, while in this review, we try to clarify all available information on the adaptations of antelopes living in arid areas to their native environments, paying particular attention to behavioral adjustments. Behavioral mechanisms, especially daily activity, diet and microclimate selection, and migrations, are so important and commonly used by antelopes in natural conditions, in which physiological mechanisms are usually not involved. Antelopes adjust their behaviors according to environmental changes so successfully that purely physiological mechanisms are discovered under laboratory conditions; for example, adaptive heterothermia or selective brain cooling phenomenon is difficult to observe in their natural habitats. This review provides a better understanding of the main behavioral mechanisms of antelope adaptations to arid environments and allows for the identification of the key factors for successful conservation of antelopes in their natural habitats.
分类： 环境科学技术及资源科学技术 >> 环境学 提交时间： 2022-10-13 合作期刊: 《干旱区科学》
摘要：There is a lack of research on soil microplastics in arid oases considering the rapid economic development of northwestern China. Here, we studied the occurrence and sources of microplastics in soil, as well as the relationships between microplastics and adsorbed heavy metals in the Ebinur Lake Basin, a typical arid oasis in China. Results showed that (1) the average microplastic content in all soil samples was 36.15 (±3.27) mg/kg. The contents of microplastics at different sampling sites ranged from 3.89 (±1.64) to 89.25 (±2.98) mg/kg. Overall, the proportions of various microplastic shapes decreased in the following order: film (54.25%)>fiber (18.56%)>particle (15.07%)>fragment (8.66%)>foam (3.46%); (2) among all microplastic particles, white particles accounted for the largest proportion (52.93%), followed by green (24.15%), black (12.17%), transparent (7.16%), and yellow particles (3.59%). The proportions of microplastic particle size ranges across all soil samples decreased in the following order: 1000–2000 µm (40.88%)>500–1000 µm (26.75%)>2000–5000 µm (12.30%)>100–500 µm (12.92%)>0–100 µm (7.15%). FTIR (Fourier transform infrared) analyses showed that polyethylene terephthalate (PET), polypropylene (PP), polycarbonate (PC), polyethylene (PE), and polystyrene (PS) occurred in the studied soil; (3) random forest predictions showed that industrial and agricultural production activities and the discharge of domestic plastic waste were related to soil microplastic pollution, in which agricultural plastic film was the most important factor in soil pollution in the study area; and (4) seven heavy metals extracted from microplastics in the soil samples showed significant positive correlations with soil pH, EC, total salt, N, P, and K contents (P<0.01), indicating that these soil factors could significantly affect the contents of heavy metals carried by soil microplastics. This research demonstrated that the contents of soil microplastics are lower than other areas of the world, and they mainly come from industrial and agricultural activities of the Ebinur Lake Basin.
分类： 环境科学技术及资源科学技术 >> 环境科学技术基础学科 提交时间： 2022-06-17 合作期刊: 《干旱区科学》
摘要： Abstract: Sand fences made of punched steel plate (PSP) have recently been applied to control wind-blown sand in desertified and Gobi areas due to their strong wind resistance and convenient in situ construction. However, few studies have assessed the protective effect of PSP sand fences, especially through field observations. This study analyzes the effects of double-row PSP sand fences on wind and sand resistance using field observations and a computational fluid dynamics (CFD) numerical simulation. The results of field observations showed that the average windproof efficiencies of the first-row and second-row sand fences were 79.8% and 70.8%, respectively. Moreover, the average windproof efficiencies of the numerical simulation behind the first-row and second-row sand fences were 89.8% and 81.1%, respectively. The sand-resistance efficiency of the double-row PSP sand fences was 65.4%. Sand deposition occurred close to the first-row sand fence; however, there was relatively little sand on the leeward side of the second-row sand fence. The length of sand accumulation near PSP sand fences obtained by numerical simulation was basically consistent with that through field observations, indicating that field observations combined with numerical simulation can provide insight into the complex wind-blown sand field over PSP sand fences. This study indicates that the protection efficiency of the double-row PSP sand fences is sufficient for effective control of sand hazards associated with extremely strong wind in the Gobi areas. The output of this work is expected to improve the future application of PSP sand fences.
分类： 环境科学技术及资源科学技术 >> 环境科学技术基础学科 提交时间： 2022-06-17 合作期刊: 《干旱区科学》
摘要： Abstract: During aeolian processes, the two most critical factors related to dust emissions are soil particle and aggregate saltation, which greatly affect the vertical profiles of near-surface dust concentrations. In this study, we measured PM10 concentrations at four different heights (0.10, 0.50, 1.00 and 2.00 m) with and without continuous and simultaneous aeolian saltation processes on a Gobi surface in northwestern China from 31 March to 10 April, 2017. We found that the vertical concentration profiles of suspended PM10 matched the log-law model well when there was no aeolian saltation. For the erosion process with saltation, we divided the vertical concentration profiles of PM10 into the saltation-affected layer and the airflow-transport layer according to two different dust sources (i.e., locally emitted PM10 and upwind transported PM10). The transition height between the saltation-affected layer and the airflow-transport layer was not fixed and varied with saltation intensity. From this new perspective, we calculated the airflow-transport layer and the dust emission rate at different times during a wind erosion event occurred on 5 April 2017. We found that dust emissions during wind erosion are primarily controlled by saltation intensity, contributing little to PM10 concentrations above the ground surface compared to PM10 concentrations transported from upwind directions. As erosion progresses, the surface supply of erodible grains is the most crucial factor for saltation intensity. When there was a sufficient amount of erodible grains, there was a significant correlation among the friction velocity, saltation intensity and dust emission rate. However, when supply is limited by factors such as surface renewal or an increase in soil moisture, the friction velocity will not necessarily correlate with the other two factors. Therefore, for the Gobi surface, compared to limiting dust emissions from upwind directions, restricting the transport of suspended dust in its path is by far a more efficient and realistic option for small areas that are often exposed to dust storms. This study provides some theoretical basis for correctly estimating PM10 concentrations in the Gobi areas.
分类： 环境科学技术及资源科学技术 >> 环境科学技术基础学科 提交时间： 2022-06-13 合作期刊: 《干旱区科学》
摘要： Abstract: Dust emission and wind erosion are widespread phenomena in arid and semi-arid regions, which have far-reaching harmful effects to the environment. This study aimed to use microbial induced carbonate precipitation (MICP) method with Bacillus sphaericus to reduce soil losses that occur in a dust-producing area due to wind erosion in the Ilam Province, Iran. Soil samples at the 030 cm depth were used and sterilized in an autoclave for 2 h at 121C and 103 kPa. Approximately 3 kg soils were weighed and poured in the 35 cm35 cm3 cm trays. Different treatments included two levels of B. sphaericus (0.0 and 0.5 OD), three levels of suspension volume (123, 264, and 369 mL), two levels of urea-chloride cementation solution (0.0 and 0.5 M), and two levels of bacterial spray (once and twice spray). After 28 d, soil properties such as soil mass loss, penetration resistance, and aggregate stability were measured. The results showed a low soil mass loss (1 g) in F14 formulation (twice bacterial spray+264 mL suspension volume+without cementation solution) and a high soil mass loss (246 g) in F5 formulation (without bacteria+264 mL suspension volume+0.5 M cementation solution). The highest (42.55%) and the lowest (19.47%) aggregate stabilities were observed in F16 and F7 formulations, respectively, and the highest penetration resistance (3.328 kg/cm2) was observed in F18 formulation. According to the final results, we recommended the formulation with twice bacterial spray, 0.5 M cementation solution, and 269 mL suspension volume as the best combination for soil surface stabilization. Furthermore, this method is environmentally friendly because it has no adverse effects on soil, water, and plants, thus, it would be an efficient approach to stabilize soil surface.
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