Subjects: Environmental Sciences, Resource Sciences >> Environmentology Subjects: Computer Science >> Other Disciplines of Computer Science submitted time 2024-01-07
Abstract： Objective The aim of this study is to develop a portable gas chromatograph, combined with machine learning, to achieve on-site VOC collection and rapid odor evaluation.
Methods We used a Convolutional Neural Network-Long Short-Term Memory (CNN-LSTM) to establish an odor intensity prediction model. Due to the small amount of data collected, we used a Generative Adversarial Network (GAN) to generate VOC data for each odor intensity category to enhance model training.
Results After generating the data, we used CNN-LSTM to establish the model again and compared it with Artificial Neural Networks (ANN), Support Vector Machines (SVM), and Gradient Boosting Decision Trees (XG-Boost). The results showed that the test accuracy after using GAN to generate data was better than the original data.
Limitations Future work will focus on further optimizing the model and expanding the dataset to improve the accuracy and stability of the prediction.
Conclusion This study shows that by using deep learning and generative adversarial networks, we can effectively predict the odor intensity inside the car, thereby improving the air quality inside the car. In addition, we will explore the application of this method to air quality prediction under other environmental conditions. This provides new possibilities for future air quality monitoring and improvement. As our equipment is portable and the model structure is small enough to be directly embedded into the device, it can achieve on-site VOC collection and rapid odor evaluation. This provides new possibilities for future air quality monitoring and improvement.
Peer Review Status:
Awaiting Review
Subjects: Environmental Sciences, Resource Sciences >> Basic Disciplines of Environmental Science and Technology submitted time 2023-12-20 Cooperative journals: 《干旱区科学》
Abstract： 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 (δ2H-H2O and δ18O-H2O) and dissolved nitrate (δ15N-NO3– and δ18O-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 Ca–Mg–HCO3 type and can be classified as fresh water, hard water, and very hard water. The range and average concentration of NO3– were 3.5–230.8 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 δ18O-H2O and δ2H-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 δ15N-NO3– and δ18O-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.
Subjects: Environmental Sciences, Resource Sciences >> Basic Disciplines of Environmental Science and Technology submitted time 2023-11-13 Cooperative journals: 《干旱区科学》
Abstract： 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.
Subjects: Environmental Sciences, Resource Sciences >> Basic Disciplines of Environmental Science and Technology submitted time 2023-10-17 Cooperative journals: 《干旱区科学》
Abstract：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.
Subjects: Survey & Drawing Science and Technology >> Photogrammetry and Remote Sensing Subjects: Environmental Sciences, Resource Sciences >> Other Disciplines of Environmental Sciences, Resource Sciences submitted time 2023-10-14
Abstract： As the first pilot ecological civilization zone in China, Fujian Province has an excellent ecological environment quality, and its ecological environment-related indices continue to be among the highest in the country. In order to investigate the causes of the excellent ecological quality in Fujian Province in the past 15 years, this paper selects MODIS images, land use data and provincial and municipal statistical yearbook data of Fujian province from 2005 to 2020 as data sources, evaluates the ecological system health of Fujian Province by remote-sensing ecological index (i.e. RSEI), constructs the land use intensity system of Fujian Province at the same time, and uses a coupled coordination model to analyse the coupling between RSEI and The coupled coordination model was used to analyse the coupling relationship between RSEI and land use intensity, and finally the spatial and temporal evolution of ecological health in Fujian Province from 2005 to 2020 was analysed. The results show that the coupled coordination between land use intensity and ecosystem health in Fujian province showed a continuous increase between 2005 and 2020, especially in Ningde, where the increase was most significant, from 0.0993 to 0.963, this pattern of spatial distribution is lower in the south-eastern coastal region than in the north-western interior, higher in the south-western region than in the north-western region, and higher in the north-eastern region than in the south-eastern region. In terms of the type of role, the land use intensity of most cities in Fujian Province in 2005 played an obvious role in blocking the degree of ecosystem health, but as time changed, urban land use continued to be optimized and reached moderate or even high quality coordination with the quality of the ecological environment, but Xiamen City developed relatively slowly and its 2020 coupling degree value was 0.315, which was still in mild disorder. This study fills a gap in the research mechanism of the interaction between the degree of ecosystem health and land use intensity, and also provides a new perspective for the construction of ecological civilization and the assessment of the degree of ecosystem health in Fujian Province and the whole country.
Subjects: Environmental Sciences, Resource Sciences >> Other Disciplines of Environmental Sciences, Resource Sciences Subjects: Computer Science >> Computer Application Technology submitted time 2023-09-22
Abstract： Objective Timely and accurate air quality prediction data is very important for environmental management, especially during the period of heavy air pollution. The prediction data can provide data support for the decision-making of the government's ecological environment management departments to cope with the pollution situation and accurately allocate social resources.
Methods The air quality prediction model AirNet6 developed by the author based on depth learning can give consideration to both accuracy and real-time performance to achieve 7-day or longer air quality prediction for ozone, sulfur dioxide, carbon monoxide and other factors.
Results Unlike traditional chemical model calculations, this model base on Spatio-Temporal Graph Convolutional Networks (STGCN), which captures the laws of historical monitoring data, weather prediction data, social activities and other data, and completes the prediction of more than one hundred points for the next 168 hours in two minutes.
Conclusions Experiments show that the AirNet6 model has made significant progress in speed, energy efficiency, and accuracy compared to traditional chemical models and time series AI models.
Subjects: Environmental Sciences, Resource Sciences >> Basic Disciplines of Environmental Science and Technology submitted time 2023-08-23 Cooperative journals: 《中国科学院院刊》
Abstract： Urban spatial structure is an important part of the research on the regional system of the human-land relationship, and it is also an important starting point for the sustainable development of cities. How to scientifically understand the urban spatial structure in the new era is the basis for optimizing its regulation. This study briefly reviews the historical background of traditional urban spatial structure theory and points out the transformational turn of urban spatial structure in terms of organizational principles, organizational methods, optimization goals and elements through the analysis of technological revolution, policy, and socio-economic environment in the new era, and clarifies the limitations of traditional urban structure theory in explaining urban structure in the new era. This study proposes a path for understanding urban spatial structure in the new era, including reconstructing the research paradigm of urban spatial structure from the theory of human-land territorial system, re-understanding the carrier space of urban spatial structure, strengthening the analysis of urban structure relationship, and innovating the measurement system of urban spatial structure. The key measures to deal with the challenges of urban spatial structure cognition in the future, namely, reconstructing the theory of urban spatial structure, integrating key technologies of urban spatial structure analysis, integrating and apply multi-source data and building a digital twin platform for urban spatial structure optimization and regulation.
Subjects: Environmental Sciences, Resource Sciences >> Basic Disciplines of Environmental Science and Technology submitted time 2023-08-23 Cooperative journals: 《中国科学院院刊》
Abstract： Mineral resources are fundamental materials for economic and social development. Irrational exploration, utilization and consumption not only undermine the security of industrial chain and supply chain, but also seriously damage ecosystem. A new round of technological revolution and carbon neutral strategy is reshaping the global innovation distribution and technical structure. As China’s economic and social development advances into post-epidemic stage, the supply and demand structure of strategic metal resources has experienced profound changes. The security challenges extend from traditional security of access to resource to the entire chains, including extraction, processing, use and recycling. China’s solid waste generation has grown rapidly along with economic development, but its recycling rate is still low, leading to the loss of a large scale of resources. In the future, the collection and recycling system of secondary metals should be enhanced, management systems for classification and grading of resources and reserves of secondary resources should be established, and national systems and standards for efficient resources utilization should be developed. The above measures are designed to guarantee the optimal internal circularity and self-sufficiency of strategic metals resources, which helps alleviate the dependence on other countries.
Subjects: Environmental Sciences, Resource Sciences >> Basic Disciplines of Environmental Science and Technology submitted time 2023-08-07
Abstract： Organic carbon burial is an important part of the carbon cycle, but there are few studies on organic carbon in coral reef sediments, which affects the accurate assessment of coral reef carbon cycle. In this paper, the modern surface sediments from the outer slope of Yongle Atoll, Xisha Islands, South China Sea, were analyzed for their total organic carbon (TOC) content, total nitrogen (TN) content, organic carbon isotope (δ13C) value, as well as sediment grain size, chlorophyll content and other indicators. The ecological condition of the outer slope of Yongle Atoll reef is relatively good, and has the potential to represent the organic carbon characteristics in sediments of healthy coral reef ecosystems. The results showed that: 1) the TOC content in the sediments from the outer slope of Yongle Atoll reef ranged from 0.71 to 1.66 mg·g-1, with an average of 1.23±0.31 mg·g-1; the TN content ranged from 0.12 to 0.28 mg·g-1, with an average of 0.20±0.05 mg·g-1. 2) the C/N ratio ranged from 6.16 to 7.59, with an average of 6.75±0.34; δ13C values ranged from -17.49 to -15.85‰, with an average of -16.61±0.49‰, indicating that the organic carbon in the sediments was predominantly of marine autochthonous origin and mainly from benthic plants. 3) Organic carbon content was negatively correlated with water depth and positively correlated with chlorophyll a content and pheophytin content, indicating that primary productivity controlled by benthic plants was the main source of organic carbon content on the outer slope of the reef. Combined with the average deposition rate of surface sediments in this area over the past 3,500 years (1.27 mm·a-1), it is hypothesized that the organic carbon burial flux on the outer slope of Yongle Atoll ranges from 1.12 to 2.61 g·m-2·a-1, with an average of 1.93±0.49 g·m-2·a-1. The present study provides new information for evaluating the contribution of coral reefs in the South China Sea to the carbon cycle.
Peer Review Status:Awaiting Review
Subjects: Environmental Sciences, Resource Sciences >> Basic Disciplines of Environmental Science and Technology submitted time 2023-08-05
Abstract： Rapid and accurate tsunami is an important part of Marine disaster prevention work, which is of great significance to Marine engineering and people's life and property safety. In this paper, based on 1-Dimensional Convolutional Neural Network (CONV1D), the evolution model of tsunami-like hydrodynamic characteristics of reef topography is constructed. By inputting observed values of wave heights resembling tsunami waves, the water inundation time series curves for specified locations on islands and reefs are generated. This achieves a prediction from one time series to another, serving the purpose of marine disaster prevention. The results indicate that the average error in predicting the arrival time of tsunami-like waves is 0.71%, and the average error in predicting maximum water levels is 6.99%. The hydrodynamic characteristics of island and reef terrains resembling tsunami waves obtained through CONV1D exhibit a strong alignment with numerical results.
Peer Review Status:Awaiting Review
Subjects: Environmental Sciences, Resource Sciences >> Environmentology submitted time 2023-02-15 Cooperative journals: 《干旱区科学》
Abstract： 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 2018–2023. 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.
Subjects: Environmental Sciences, Resource Sciences >> Environmental Engineering submitted time 2023-01-11
Abstract：
Under the background of ecological civilization construction, it is very important for the development of rural revitalization to implement General Secretary Xi Jinping's "Lucid waters and lush mountains are invaluable assets" concept and explore the realization of ecological resources value based on the ecological bank model.This paper sorts out the existing modes and practices of ecological resource value transformation, that is, ecological asset property right transaction mode, ecological industry practice mode, diversified product value realization mode and ecological compensation practice mode, and analyzes and sums up the problems existing in the four modes, such as large government funding gap, weak financial attributes and low enthusiasm for investment and management.On this basis, a new path of ecological resource value transformation under the innovative eco-bank model in the new era is designed. This model can drive the transformation of ecological resources value and the development of rural revitalization, and bring ecological and economic benefits to rural areas.
Peer Review Status:Awaiting Review
Subjects: Environmental Sciences, Resource Sciences >> Basic Disciplines of Environmental Science and Technology submitted time 2022-12-12 Cooperative journals: 《干旱区科学》
Abstract： 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.
Subjects: Environmental Sciences, Resource Sciences >> Basic Disciplines of Environmental Science and Technology submitted time 2022-11-12 Cooperative journals: 《干旱区科学》
Abstract： 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.
Subjects: Environmental Sciences, Resource Sciences >> Basic Disciplines of Environmental Science and Technology submitted time 2022-11-08 Cooperative journals: 《干旱区科学》
Abstract： 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.
Subjects: Environmental Sciences, Resource Sciences >> Basic Disciplines of Environmental Science and Technology submitted time 2022-11-08 Cooperative journals: 《干旱区科学》
Abstract：
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.
Subjects: Environmental Sciences, Resource Sciences >> Environmentology submitted time 2022-10-13 Cooperative journals: 《干旱区科学》
Abstract： 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.
Subjects: Environmental Sciences, Resource Sciences >> Basic Disciplines of Environmental Science and Technology submitted time 2022-06-17 Cooperative journals: 《干旱区科学》
Abstract：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.
Subjects: Environmental Sciences, Resource Sciences >> Basic Disciplines of Environmental Science and Technology submitted time 2022-06-17 Cooperative journals: 《干旱区科学》
Abstract：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.
Subjects: Environmental Sciences, Resource Sciences >> Basic Disciplines of Environmental Science and Technology submitted time 2022-06-13 Cooperative journals: 《干旱区科学》
Abstract：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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