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Stable isotopes in natural water bodies serve as hydrologic tracers, with a history of extensive application in karst groundwater research. The present paper is a systematic review of previous research results, with the objective of sorting out and summarizing the stable isotopic characteristics of karst groundwater in southwest China, which is the most typical karst region worldwide. Comprehensive analysis reveals that the deuterium and oxygen isotope values of most karst groundwater are characterized temporally as 'enriched in the rainy season and depleted in the dry season', which is the opposite of the pattern of precipitation. While the spatial distribution feature is basically consistent with the spatial variation pattern of precipitation, which is characterized as 'depleted from the coast to the interior'. Additionally, the main applications of stable isotopes to karst groundwater are discussed, including karst groundwater recharge source and recharge elevation identification, research on karst groundwater in the hydrological cycle, the hydrological process of karst groundwater, and karst groundwater contamination tracking. Finally, we looked forward to future research on karst groundwater based on deuterium and oxygen isotopes. It is our hope that this review may provide insight into the study of karst groundwater. [ABSTRACT FROM AUTHOR]

With escalating human activities and the substantial emissions of greenhouse gases, global warming intensifies. This phenomenon has led to increased occurrences of various extreme hydrological events, precipitating significant changes in lakes and rivers across the Qinghai Tibet Plateau. Therefore, accurate information extraction about and delineation of water bodies are crucial for lake monitoring. This paper proposes a methodology based on the Normalized Difference Water Index (NDWI) and Gumbel distribution to determine optimal segmentation thresholds. Focusing on Qinghai Lake, this study utilizes multispectral characteristics from the US Landsat satellite for analysis. Comparative assessments with seven alternative methods are conducted to evaluate accuracy. Employing the proposed approach, information about water bodies in Qinghai Lake is extracted over 38 years, from 1986 to 2023, revealing trends in area variation. Analysis indicates a rising trend in Qinghai Lake's area following a turning point in 2004. To investigate this phenomenon, Pearson correlation analysis of temperature and precipitation over the past 38 years is used and unveils the fact that slight precipitation impacts on area and that there is a positive correlation between temperature and area. In conclusion, this study employs remote sensing data and statistical analysis to comprehensively investigate mechanisms driving changes in Qinghai Lake's water surface area, providing insights into ecological shifts in lake systems against the backdrop of global warming, thereby offering valuable references for understanding and addressing these changes. [ABSTRACT FROM AUTHOR]

[Objective] The Grand Canal is a complex hydraulic project in the eastern China. This paper studies the flooding and its detrimental impacts in the lowland areas of the canal. [Method] The research was conducted in the Pichang-Tanxin Plain, using multi-source remote sensing data and ground surveys to analyze flooding events. We calculated the normalized difference water body index (NDWI) and the normalized difference vegetation index (NDVI) before and after flooding to assess flood severity, impact on crop growth, as well as the efficacy of hydraulic facilities in mitigating flooding effects. [Result] The NDVI difference between 2004 and 2005 for crops in flooded and non-flooded areas was 0.5 and 0.25, respectively, indicating floodings detrimentally affected crop growth and development. NDWI analysis from 2003 to 2017 demonstrated that the Taierzhuang Control Gate project mitigated flooding impacts on nearby farmlands. Flooding also affected crops in non-inundated regions, with lowland crops more adversely impacted than those outside lowlands. The hydraulic facilities significantly reduced economic losses caused by flooding. [Conclusion] Remote sensing is an effective tool for monitoring inundated areas and assessing the consequences of flooding on crops. The construction of hydraulic facilities plays a crucial role in reducing the detrimental effects of flooding in lowland regions of the Grand Canal. [ABSTRACT FROM AUTHOR]

The consumption of bisphenol A (BPA) in China has been steadily increasing as a popular plastic additive. However, it is also recognized as a typical environmental endocrine disruptor. Even at low concentrations, prolonged exposure to BPA can lead to neurotoxicity, liver toxicity, reproductive toxicity, immunotoxicity and other adverse effects, contributing to various diseases such as diabetes, inflammation, obesity, anxiety, depression and even cancer. In recent years, BPA has been detected in various environmental water bodies in China due to water pollution caused by industrial development and plastic waste discharge. Furthermore, the level of BPA exposure in each water sample varies depending on geographic regions, seasonal temperature variations, and other factors. This paper presents the latest research advancements in understanding the multiple toxic effects and strategies for mitigating the toxicity of BPA. It also provides a comprehensive summary of BPA pollution levels in various environmental water bodies in China over the past decade, along with an analysis and discussion of influencing factors. The aim is to offer valuable insights for studying population exposure doses and health risks associated with BPA. [ABSTRACT FROM AUTHOR]

The "Yangtze River Economic Belt Development Strategy" is one of China's three major national development strategies. Enhancing the protection and quality of arable land in the Yangtze River Economic Belt (YEB) is pivotal for fostering regional growth. In this study, land use data spanning the years 1980 to 2020 in the YEB were extracted from the national land use database maintained by the Resource and Environment Data Center of the Chinese Academy of Sciences. Employing Geographic Information System (GIS) spatial analysis techniques and arable land change metrics, the study delineated the spatiotemporal characteristics of arable land alterations across the YEB for the period. Additionally, using grain output data at the prefecture level from 2011 to 2020, the paper calculated provincial grain output to analyze the impact of arable land changes over the last four decades on grain output. The findings revealed that: (1) From 1980 to 2020, the total arable land area in the YEB decreased by approximately 41,775 square kilometers, with the most significant decrease occurring in the downstream region. (2) From 1980 to 1990, the primary factor contributing to the decrease in arable land area was the expansion of water bodies, while from 1990 to 2020, the principal reason for the reduction in arable land area was the expansion of construction land. (3) From 1980 to 2020, the decrease in arable land area resulted in a net reduction of approximately 25.12 million tons in total grain output, with the largest decline observed in the downstream regions and the smallest decline in the upstream regions. (4) Consistent with the trends in arable land area reduction, the main reason for the decline in grain output from 1980 to 1990 was the expansion of water bodies encroaching upon arable land, whereas from 2000 to 2010, the primary cause of arable land reduction was the expansion of construction land areas. In conclusion, the research suggested that over the past four decades, the primary driver behind the reduction in arable land within the YEB has been the expansion of construction land areas. Particularly noteworthy was the period from 2000 to 2010, during which the impact of arable land reduction on grain output was most pronounced. This period coincided with the rapid economic development and accelerated urbanization process within the YEB. [ABSTRACT FROM AUTHOR]

DO is an important index to characterize environmental water quality. The time series fluctuation of DO can be analyzed via frequency band decomposition, which is very valuable for water quality simulations. In this paper, DO in the Chengdu area of China was studied using variational mode decomposition with daily meteorological data and water quality data from 2020 to 2022. After variable decomposition, the DO data were first decomposed into different frequency band signals named IMF1, IMF2, IMF3, IMF4, and IMF5. IMF1 represented the low-frequency signal with long-term trend characteristics of the data. IMF2 to IMF5 represented the high-frequency signal with short-term mutation characteristics of the data. By combining the variable decomposition results with the correlation analysis, it was found that the long-term trend characteristics of DO are affected by the superposition of meteorological factors, hydrological factors, and water pollution factors but have a weak correlation with any single determining factor. The air temperature, water temperature, phosphorus, air pressure, pH value, chemical oxygen demand, and nitrogen were relatively strongly correlated with the long-term trend characteristics of DO. The short-term mutation characteristics of DO were mainly determined using the characteristics of the water body itself, while the influence of the meteorological factors could basically be ignored. The water temperature, pH value, and eutrophication were the biggest influencing factors. Then, a predictive framework combining frequency division with a deep learning model or a machine learning model was constructed to predict DO. The predicted results of GRU, random forest, and XGBoost with and without the framework were compared. It was shown that, after removing the interference factors with correlations less than 0.3, the predicted value of DO was much closer to the actual value. The XGBoost and random forest models with decomposed signals had a high degree of simulation fitting and could be used to predict DO in the Chengdu area. The above research approach can be applied to further explore the prediction of various pollution factors in different areas of China. [ABSTRACT FROM AUTHOR]

Along with the accelerating urbanization process in China, the problem of urban infrastructure layout has become increasingly prominent. The high density of buildings and the extremely unreasonable distribution of infrastructure make the development face great resistance. This paper reveals the problems in the layout of garden infrastructure by studying and analyzing the theoretical foundations of federal learning and distributed learning and provides an in-depth analysis and elaboration of the problem. The paper uses the shape index and landscape index of green infrastructure (green space, arable land, and water bodies), the average width of roads, road network density, and weighted buildings to conduct a comparative study through the differences in ventilation speed and temperature at different layout garden scales. According to the problems existing in the garden layout in the experimental results, corresponding improvement measures are targeted, and the infrastructure layout of the garden is combined with ecology to make the layout within the garden more suitable. [ABSTRACT FROM AUTHOR]

The salinity of the salt lake is an important factor to evaluate whether it contains some mineral resources or not, the fault buried in the salt lake could control the abundance of the salinity. Therefore, it is of great geological importance to identify the fault buried in the salt lake. Taking the Gasikule Salt Lake in China for example, the paper established a new method to identify the fault buried in the salt lake based on the multi‐source remote sensing data including Landsat TM, SPOT‐5 and ASTER data. It includes the acquisition and selection of the multi‐source remote sensing data, data preprocessing, lake waterfront extraction, spectrum extraction of brine with different salinity, salinity index construction, salinity separation, analysis of the abnormal salinity and identification of the fault buried in salt lake, temperature inversion of brine and the fault verification. As a result, the study identified an important fault buried in the east of the Gasikule Salt Lake that controls the highest salinity abnormal. Because the level of the salinity is positively correlated to the mineral abundance, the result provides the important reference to identify the water body rich in mineral resources in the salt lake. [ABSTRACT FROM AUTHOR]

This paper analyzes data on the chemical composition of wetland waters, groundwaters, and river waters in the catchment area of Poyang Lake, which were obtained in the course of Russian–Chinese hydrogeochemical studies in 2013–2022. The bulk of the laboratory work was carried out at Tomsk Polytechnic University using the mass spectrometric method with inductively coupled plasma. It is shown that wetlands that are not used economically are a source of organic substances and their transformation products entering the groundwater of the upper hydrodynamic zone. An anthropogenic impact on surface and groundwaters has also been established, which manifests itself in a rather sharp increase in the concentrations of certain chemical elements and their compounds. However, at the same time, a significant ability of the region's water bodies to self-purify has been revealed. Thus, in the low-water periods of 2019 and 2022, a decrease in the contents of As, Cd, Ni, Sb, V, Mo, and W in the waters of the Jinjiang River was noted, which is 17–120 times and more just 100–200 m downstream from wastewater outlets. Based on the analysis of measurement results, thermodynamic calculations, mathematical modeling of hydrogeochemical processes, and published materials of other authors, it is concluded that the most likely explanation for this ability is a combination of the following factors: the precipitation of poorly soluble substances (calcium and magnesium humates and carbonates and clay minerals) with the total content of dissolved salts amounting to more than 300–400 mg/dm3; the coprecipitation of a number of microelements, which increases with a decrease in the effective diameter of sediment particles (0.003 mm or less); and the involvement of substances removed from the solution in biogeochemical processes, the intensity of which increases under favorable climatic conditions (such as in the catchment area of Poyang Lake). [ABSTRACT FROM AUTHOR]

The escalation in carbon dioxide concentration has precipitated global climate warming, accentuating ecological and environmental concerns. Notably, China stands as the world's largest carbon emitter, with the Taihu Lake basin emerging as a carbon-intensive region within the country. This paper undertakes a comprehensive analysis spanning 2005 to 2020, calculating the economic contribution coefficient of carbon emissions and the ecological carrying coefficient of carbon absorption in the Taihu Lake basin. The study includes a delineation of carbon balance zones and an exploration of the geographical and spatial influences of both ecosystem and economic factors. The overarching trend in carbon emissions within the Taihu Lake Basin initially exhibited rapid growth, followed by a fluctuating decline, with the pivotal year being 2012, recording the apex of emissions at 575.8293 million tons. Concurrently, total carbon absorption demonstrated a fluctuating growth trajectory, ascending from 82.3503 million tons in 2005 to 85.6488 million tons in 2020. The carbon emission intensity in the basin manifested a pattern of high concentration in the northeast and low concentration in the southwest, while the carbon absorption intensity displayed the inverse pattern. The carbon balance across the Taihu Lake Basin revealed a spatial incongruity, characterized by a suboptimal pattern in the northeast and a favorable pattern in the southwest. Zhejiang Province emerged as an ecological stronghold within the basin, acting as the primary carbon sink functional area. Urban built-up areas and forested regions emerged as principal influencers of carbon balance in the Taihu Lake basin. Urban construction land, population density, and arable land area were identified as primary contributors to carbon emissions, whereas per capita GDP, forests, grasslands, and water bodies were identified as main contributors to carbon absorption in the watershed. [ABSTRACT FROM AUTHOR]

The extensive accumulation of big data, along with the development of a high-performance platform, bridge the gap between the previous inability to provide long-term time series and broad-scale coastal zone monitoring and risk warnings with remote sensing techniques. Based on 20 years of Landsat images from the Google Earth Engine platform, the time series land cover in the coastal zone of the Yangtze River Delta in China was classified. Then, a spatiotemporal clustering method based on grid segmentation was proposed to analyze the spatiotemporal evolution details of artificial surface expansion and the risks of cropland loss and ecological degradation caused by this. The results showed that significant changes have taken place in the quantitative structure and spatial morphology of coastal land use in the past 20 years. The artificial surface maintained a growth trend, increasing by 229%, while cropland decreased by 19%. Natural land showed a fluctuation pattern of "up→down→up". The spatiotemporal details of land use obtained through 1km grid segmentation and clustering analysis were more significant. The artificial surface mainly underwent a progressive spatial expansion along the central urban area and important transportation axes (types III and IV), with the most dramatic changes occurring from 2010 to 2013. Type III cropland loss was the most significant, falling from 75.02% in 2000 to 38.23% in 2020. At the same time, the change in type III water body corresponds to the newly increased area of reclamation, which has decreased by 17% in the past 20 years, indicating that the degradation of coastal natural wetlands was significant. This paper provided a comprehensive diagnosis of coastal land use change, which could help policy makers and implementers to propose more targeted and differentiated coastal development and protection policies. [ABSTRACT FROM AUTHOR]

Copyright of Landscape Architecture Frontiers is the property of Higher Education Press Limited Company and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The South-to-North Water Diversion East Project (SNWDP-E) is an effective way to realize the optimal allocation of water resources in China. The North Dasha River (NDR) is the reverse recharge section that receives water from the Yufu River to the Wohushan Reservoir transfer project line in the SNWDP. However, the dissolved organic matter (DOM) evolution mechanism of seasonal water transfer projects on tributary waters has not been fully elucidated. In this paper, the NDR is the main object, and the changes in the composition and distribution of spectral characteristics during the winter water transfer period (WT) as well as during the summer non-water transfer period (NWT) are investigated by parallel factor analysis (PARAFAC). The results showed that the water connectivity caused by water transfer reduces the environmental heterogeneity of waters in the basin, as evidenced by the ammonia nitrogen (NH4+-N) and total phosphorus (TP) in the water body were significantly lower (p<0.05, p<0.01) during the water transfer period than the non-water transfer period. In addition, the fluorescence intensity of DOM was significantly lower in the WT than the NWT (p<0.05) and was mainly composed of humic substances generated from endogenous sources with high stability. While the NWT was disturbed by anthropogenic activities leading to significant differences in DOM composition in different functional areas. Based on the redundancy analysis (RDA) and multiple regression analysis, it was found that the evolution of the protein-like components is dominated by chemical oxygen demand (COD) and NH4+-N factors during the WT. While the NWT is mainly dominated by total nitrogen (TN) and TP factors for the evolution of the humic-like components. This study helps to elucidate the impact of water transfer projects on the trunk basin and contribute to the regulation and management of inter-basin water transfer projects. [ABSTRACT FROM AUTHOR]

Marsh wetlands are significant ecosystems located between land and water bodies which can both protect species diversity and provide habitats. Changes in the hydrological situation of marsh wetlands as a result of climate change and human activities have led to the degradation of wetland landscapes. Taking the Honghe National Nature Reserve (HNNR) in Heilongjiang Province, China, as an example, this paper gathered information on the reserve's wetland landscape before and after dam construction. The information was obtained using field survey data and a random forest classification method based on Landsat data powered by the Google Earth Engine (GEE) cloud platform. Then, on the basis of the water level data and the digital elevation model, the wetland landscape dynamics of HNNR under three water level conditions were simulated. The findings were as follows: (1) From 1998 to 2008, the area of marsh and meadow had a downward trend, while the area of forest, farmland and water showed a gradual and upward trend; a marked rise in the area of marsh and a continued rise in the area of forest, farmland and water, and a sharp decline in the area of meadow during 2008 to 2018 was observed. (2) There was a significant increase in the area of marsh under the 20 and 40 cm water level simulation scenarios, with a decrease in the number of patches, and an increase in the aggregation index with rising water levels; in contrast, when the water level rose to 60 cm, the area of marsh and the number of patches decreased, but the aggregation index continued to increase. (3) The correlation between wetland landscape and the water level was a nonlinear one. The area of marsh increased and then decreased with increasing water level, reaching a maximum at the 40 cm water level; therefore, 40 cm was the optimal water level regulation scenario. Hydrological processes are the most fundamental ecological processes in marsh wetlands. Understanding the scientific pattern of the spatial pattern characteristics of species as a function of water level environment is important for scientifically guiding the restoration of marsh vegetation. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In recent years, China has launched a number of Gaofen (GF) series earth observation satellites. It is crucial to understand the relationship between the data of the GF series of satellite sensors for the selection of sensor images for scientific research. Taking the same-day transit image pairs of three regions as the study data, this paper compares the consistency of the Top of Atmosphere (TOA) reflectance of GF-1 WFV4 and GF-6 WFV sensors by using the TOA mean comparison method, and discusses the differences in water body and vegetation extraction. The results indicate that the satellite signal intensity in different land cover types and areas differs significantly. In the bare soil-dominated region, GF-1 WFV4 has a larger signal strength than GF-6 WFV, while in the vegetation-dominated region, it turns out to be just the opposite. The difference between the two sensors is mainly related to the difference in the spectral response function and the radiometric resolution of the two satellites. In addition, the determination coefficient (R2) of the corresponding bands of the two sensors is all greater than 0.90, indicating that the two sensors have strong linear correlation and good complementarity. [ABSTRACT FROM AUTHOR]

Rapidly monitoring regional water quality and the changing trend is of great practical and scientific significance, especially for the Beijing-Tianjin-Hebei (BTH) region of China where water resources are relatively scarce and inland water bodies are generally small. The remote sensing data of the GF1 satellite launched in 2013 have characteristics of high spatial and temporal resolution, which can be used for the dynamic monitoring of the water environment in small lakes and reservoirs. However, the water quality remote sensing monitoring model based on the GF1 satellite data for lakes and reservoirs in BTH is still lacking because of the considerable differences in the optical characteristics of the lakes and reservoirs. In this paper, the typical reservoirs in BTH-Guanting Reservoir, Yuqiao Reservoir, Panjiakou Reservoir, and Daheiting Reservoir are taken as the study areas. In the atmospheric correction of GF1-WFV, the relative radiation normalized atmospheric correction was adopted after comparing with other methods, such as 6S and FLAASH. In the water clarity retrieval, a water color hue angle based model was proposed and outperformed other available published models, with the R2 of 0.74 and MRE of 31.7%. The clarity products of the four typical reservoirs in the BTH region in 2013–2019 were produced using the GF1-WFV data. Based on the products, temporal and spatial changes in clarity were analyzed, and the main influencing factors for each water body were discussed. It was found that the clarity of Guanting, Daheiting, and Panjiakou reservoirs showed an upward trend during this period, while that of Yuqiao Reservoir showed a downward trend. In the influencing factors, the water level of the water bodies can be an important factor related to the water clarity changes in this region. [ABSTRACT FROM AUTHOR]

A bibliometric analysis using the Scopus database was performed to investigate the research documents published from 1990 to 2019 in scientific sources related to molybdenum in drinking water and determine the quantitative characteristics of the research in this period. The results from the analysis revealed that the number of publications was maintained at a regular production of around 5 papers per year until 2009, followed by a fast linear increase in the production in the period from 2010 to 2016 (29 papers in 2016), but the scientific production regarding this topic was reduced in 2017 and 2018 to recover the production obtained in 2016 once again in 2019. The total contribution of the three most productive countries (USA, China and India, respectively) accounted for around 50% of the total number of publications. Environmental Science was the most common subject (51.4% contribution), followed by Chemistry (26.7% contribution). The research efforts targeted toward the search for technical solutions for molybdenum removal from water are not as important as the ones focused on the identification of molybdenum-polluted water bodies and the analysis of the health effects of the intake of molybdenum. Nevertheless, examples of technological treatments to remove molybdenum from the aqueous solution include the use of adsorption and ion exchange; coagulation, flocculation and precipitation followed by filtration; membrane technologies and biological treatments. [ABSTRACT FROM AUTHOR]

Reasonable planning of the limited land resources can promote the coordinated development of social economic and ecological protection. It is very important to optimize the rational distribution of land resources in the arid inland river basin because of the scarce land. In this paper, the GIS technologies of spatial analysis, conversion of land use, and its effects at small regional extent (CLUE-S) and minimum cumulative resistance (MCR) model were used to optimize the land allocation. The ecological security pattern (ESP) was constructed through using MCR model, which included ecological source and resistance surface. The dynamics of land use and spatial optimizing allocation of Shiyang River Basin in 2025 and 2030 was simulated under three different optimization scenarios including farmland protection scenario (FPS), free development scenario (FDS), and ecological security pattern scenario (ESPS). It was found that under ESPS, farmland was reduced, but woodland, grassland, and water body were increased significantly. Under FPS, land for construction was controlled effectively, a large part of homestead was converted into farmland, and the potential of unused land was developed vigorously. Furthermore, the current FDS and macro policy guidance should be comprehensively considered. The ESPS was more suitable for the scientific development of Shiyang River Basin on a long view. The combination of CLUE-S and MCR can effectively improve the optimization methods under ecological process and ecological resistance of landscape elements. [ABSTRACT FROM AUTHOR]

Remote sensing images and related stereoscopic illusions, such as stereoscopic illusion, often confuses engineers and technicians. In order to utilize the beneficial illusion and eliminate the harmful one, this paper studied the relationship between graphics and background from the Necker Cube in visual psychology. Through experiments and engineering practice, this paper further analyzed the types, principles and conditions of stereoscopic illusion in remote sensing image railway engineering mapping, and discussed its application and correction methods. The conclusions are as follows: (1) Stereoscopic illusion is common in remote sensing images of mountainous areas in the northern hemisphere, and the first and second steps of terrain in China are typical. (2) The three geomorphic types that produce stereoscopic illusion are: sinusoidal continuous mountain area, "Π" platform and "U" gully. (3) The causes of stereoscopic illusion include sunshine conditions, image resolution and image contrast. (4) The stereoscopic illusion of water body can be divided into three situations: bulge effect, confusion effect between bulge and depression, and depression effect. (5) The stereo illusion of remote sensing images of sinusoidal topography and Π-shaped gullies can be corrected by DEM rendering method and 3D scene method, U-shaped gullies can be corrected by 3D scene method only. [ABSTRACT FROM AUTHOR]

The ecological health of water quality is an essential factor in the survival and development of human beings. By setting up multiple sensors in the water body, people observe the factual state of water quality, and collect a large number of sequence data containing time information. In order to effectively utilize water quality time series data and predict future water quality changes, this paper proposes an improved deep learning method based on spatiotemporal feature correlated, called the convolution recurrent basis expansion analysis architecture. The model improves the original model by using the ability of convolutional neural network structure to extract spatial features and the continuous memory ability of recurrent neural network structure. Then, the physical prior knowledge is integrated into the proposed network to limit the unreasonable results predicted in the feasible solution space to further improve the learning efficiency of the model. For specific research objects, the model can mine multi-dimensional features in water quality sequences at different depths, and learn the temporal features of the sequences hierarchically. In order to verify the performance of the proposed model, we apply the proposed model to the water quality dataset collected in Tanghe Reservoir for simulation. The results of the study demonstrate that our model is suitable for water quality prediction and has distinct advantages over traditional neural networks. Our model will make accurate predictions of future changes in water quality and provide technical support in the refined water quality automatic monitoring system. [ABSTRACT FROM AUTHOR]

Level set method has been extensively used for image segmentation, which is a key technology of water extraction. However, one of the problems of the level-set method is how to find the appropriate initial surface parameters, which will affect the accuracy and speed of level set evolution. Recently, the semantic segmentation based on deep learning has opened the exciting research possibilities. In addition, the Convolutional Neural Network (CNN) has shown a strong feature representation capability. Therefore, in this paper, the CNN method is used to obtain the initial SAR image segmentation map to provide deep a priori information for the zero-level set curve, which only needs to describe the general outline of the water body, rather than the accurate edges. Compared with the traditional circular and rectangular zero-level set initialization method, this method can converge to the edge of the water body faster and more precisely; it will not fall into the local minimum value and be able to obtain accurate segmentation results. The effectiveness of the proposed method is demonstrated by the experimental results of flood disaster monitoring in South China in 2020. [ABSTRACT FROM AUTHOR]

Among water blooms, cyanobacteria bloom occurs over the widest range and is much more harmful than other blooms. Its occurrence in inland water bodies is affected by many factors, such as meteorology, hydrology, and human activities. Therefore, the study of the causes of cyanobacterial bloom has become a major focus of scholars. The China Knowledge Network Journal Database contains 143 papers from China and abroad from the years 2004 to 2019 that are relevant to the study of cyanobacteria bloom. We begin by analyzing keywords in these studies and creating a keyword distribution map which indicates the factors related to the blooms. Based on parameters such as the frequency of words appearing in the text, the full text of each of the 143 papers is analyzed to form a word cloud created by a program written in Python language. After irrelevant terms are eliminated, the word cloud map can reveal potential factors that were not identified by keywords alone. After completing this macro analysis, we examined approximately 100 related papers from the China Knowledge Network Journal Database and Web of Science Database published from 2014 to 2019. Finally, we summarize the main reasons for the outbreak of water blooms. The factors causing blooms can be divided into natural factors and human factors. Among the natural factors are illumination, water temperature and nutrient salt conditions. The human factors are generally related to large-scale water conservancy projects. This paper analyzes and summarizes these factors, and provides a reference to aid in the prevention and treatment of algal blooms. The information in the paper has a certain practical significance for the protection of water environments. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to analyze the characteristics of spatio-temporal dynamics and the evolution of land use change is essential for understanding and assessing the status and transition of ecosystems. Such analysis, when applied to Horqin sandy land, can also provide basic information for appropriate decision-making. Design/methodology/approach: By integrating long time series Landsat imageries and geographic information system (GIS) technology, this paper explored the spatio-temporal dynamics and evolution-induced land use change of the largest sandy land in China from 1983 to 2016. Accurate and consistent land use information and land use change information was first extracted by using the maximum likelihood classifier and the post-classification change detection method, respectively. The spatio-temporal dynamics and evolution were then analyzed using three kinds of index models: the dynamic degree model to analyze the change of regional land resources, the dynamic change transfer matrix and flow direction rate to analyze the change direction, and the barycenter transfer model to analyze the spatial pattern of land use change. Findings: The results indicated that land use in Horqin sandy land during the study period changed dramatically. Vegetation and sandy land showed fluctuating changes, cropland and construction land steadily increased, water body decreased continuously, and the spatial distribution patterns of land use were generally unbalanced. Vegetation, sandy land and cropland were transferred frequently. The amount of vegetation loss was the largest. Water body loss was 473.6 km2, which accounted for 41.7 per cent of the total water body. The loss amount of construction land was only 1.0 km2. Considerable differences were noted in the rate of gravity center migration among the land use types in different periods, and the overall rate of construction land migration was the smallest. Moreover, the gravity center migration rates of the water body and sandy land were relatively high and were related to the fragile ecological environment of Horqin sandy land. Originality/value: The results not only confirmed the applicability and effectiveness of the combined method of remote sensing and GIS technology but also revealed notable spatio-temporal dynamics and evolution-induced land use change throughout the different time periods (1983-1990, 1990-2000, 2000-2010, 2010-2014, 2014-2016 and 1983-2016). [ABSTRACT FROM AUTHOR]

The water source reservoirs are the important urban water source in northern China. Although external pollution has been greatly improved, the internal pollutants in reservoirs continue to accumulate with the complex deposition and release processes, resulting in potential risks to water supply safety. To address the aforementioned issue, this paper proposed a simulation model of water quality named ECOlab EU1-WSR to simulate the spatio-temporal changes of water quality under the influence of internal pollution for the water source reservoirs. Based on the analysis of the water quality characteristics and the distribution of benthic vegetation in the reservoir, a three-dimensional hydrodynamic model was established based on MIKE3, the corresponding parameters and the related state variables were set, the ECOlab EU1-WSR model was established by secondly developing the original ECOlab EU1 template, and the real-time dynamic outputs of pollutant content in sediment were added to link the water quality index with sediment nutrition index for better revealing the impact of the internal pollution on the water quality. The performance of the model was evaluated by the case application on the water quality simulation of Daye reservoir and the optimization of the connection project between Daye reservoir and Xueye reservoir in Shandong Province China. The results showed that the model can accurately and simultaneously simulate the pollution in water and sediment by the comparative verification of hydrodynamics, water temperature, and water quality. Moreover, the model can effectively reflect the influence of the accumulation, deposition, and release of internal pollution on water quality by analyzing the correlation between the content of various pollution in water body and those in sediment, such as the total nitrogen and total phosphorus in the water body at the bottom of the water intake, were negatively correlated with the total nitrogen and total phosphorus in the sediments with correlation coefficients of 0.538 and 0.917, respectively. In addition, the optimal water inlet position and water flow rate of the connection project can be optimized and determined by using the model to effectively control water quality. The established model will be a useful tool for the design and management of a reservoir, the interconnection projects, and other water bodies by adaptively recoded. [ABSTRACT FROM AUTHOR]

The Danjiang River basin is an important water source for the Middle Route of the South-to-North Water Diversion Project. With the shortage of water resources and the increase in pollution pressure, it is of great significance to study the hydrochemical characteristics of surface water in the Danjiang River basin and the risk to human health posed by polluted water bodies for the protection and utilization of water resources. In this paper, 40 surface water samples were collected and analyzed by innovatively adopting the sampling principle of "geological structure unit + landform unit + small watershed unit". Comprehensive mathematical statistical analysis, Piper trilinear diagrams, Gibbs diagrams, and ion ratio coefficients were used to analyze the hydrochemical composition, spatial distribution characteristics and influencing factors of surface water in the Danjiang River. The entropy weight comprehensive index method (EWQI) and the health risk assessment model recommended by the United States Environmental Protection Agency (HHRA model) were used to evaluate the water quality and potential non-carcinogenic risk of surface water in the Danjiang River source basin. The results showed that the pH of surface water in the study area was 7.02~8.77, with an average value of 8.26; and the TDS was ranged from 134 to 388 mg/L, with an average value of 252.75 mg/L. The main cations in the surface water were Ca2+ and Mg2+, accounting for 71% and 20% of the total cations, respectively, while the main anions were HCO3− and SO42−, accounting for 74% and 19% of the total anions, respectively. The hydrochemical type was HCO3− Ca·Mg. The hydrochemical genesis was mainly controlled by the weathering of carbonate rocks, while some ions were influenced by the weathering of silicate rocks, and human activities were also an important factor affecting the chemical characteristics of the water. The EWQI of surface water in the whole region was 8.95~25.69, and the health risk index (HI) of nitrate pollution ranged from 0.0122 to 0.2118, in which the HI ranges for children and adults were 0.0217~0.2118 and 0.0122~0.1333, respectively, indicating that the water quality of the entire study area met the Class I water standards, and the potential non-carcinogenic risk of nitrate was low. However, its impact on children was significantly higher than on adults, so it is recommended to monitor the water quality downstream of urban areas in the study area to reduce agricultural non-point source pollution and urban domestic sewage discharge and thereby reduce the potential health risks for young populations. [ABSTRACT FROM AUTHOR]

Total phosphorus (TP) concentration is high in countless small inland waterbodies in Hubei province, middle China, which is threating the water environment. However, there are almost no ground-based water quality monitoring points in small inland waterbodies, because the cost of time, labor, and money is high and it does not meet the needs of spatiotemporal dynamic monitoring. Remote sensing provides an effective tool for TP concentration monitoring spatiotemporally. However, monitoring the TP concentration of small inland waterbodies is challenging for satellite remote sensing due to the inadequate spatial resolution. Recently, unmanned aerial vehicles (UAV) have been applied to quantitatively retrieve the spatiotemporal distribution of TP concentration without the challenges of cloud cover and atmospheric effects. Although state-of-the-art algorithms to retrieve TP concentration have been improved, specific models are only used for specific water quality parameters or regions, and there are no robust and reliable TP retrieval models for small inland waterbodies at this time. To address this issue, six machine learning methods optimized by intelligent optimization algorithms (IOA-ML models) have been developed to quantitatively retrieve TP concentration combined with the reflectance of original bands and selected band combinations of UAV multispectral images. We evaluated the performances of models in terms of coefficient of determination (R2), root mean squared error (RMSE), and residual prediction deviation (RPD). The results showed that the R2 of the six IOA-ML models for training, validation, and test sets were 0.8856–0.984, 0.8054–0.8929, and 0.7462–0.9045, respectively, indicating the methods had high precision and transferability. The extreme gradient boosting optimized by genetic algorithm (GA-XGB) performed best, with the highest precision for the validation and test sets. The spatial distribution of TP concentration of each flight derived from different models had similar distribution characteristics. This paper provides a reference for promoting the intelligent and automatic level of water environment monitoring in small inland waterbodies. [ABSTRACT FROM AUTHOR]

At present, there is relatively little research on the synergistic effects of heavy metals in soil, sediment, and bedrock on heavy metal pollution in water bodies. In this paper, heavy metals in soil, sediment, bedrock, and water of a typical karst watershed in southwest China were investigated. The results indicated that the average values of heavy metals in soil and sediment were relatively higher than those in bedrock except for Ni and As. During the research period, As and Cd were the main heavy metal elements polluting the soil and sediment in the study area, while water bodies were mainly polluted by Ni, As, and Cd. The pollution assessment indicated that there were instances of poor or very poor water quality in the study area during the study period; the soil as a whole was slightly polluted by Cd and As; sediment was subject to moderate Cd pollution and mild As pollution. Analysis of geochemical form for heavy metals showed that heavy metals in soil and sediment were mainly in residual form, and the proportions of exchangeable As and Cd were relatively high. Multiple statistical analysis showed that heavy metals in sediment, soil, and bedrock explained 23.8%, 16. 8%, and 16. 2% of the changes in heavy metals of water, respectively. The research results Can provide scientific basis for the prevention and control of heavy metal pollution in water bodies. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Surface water is the most important and common water resource on earth. Accurate and effective mapping and detecting of surface water have been made possible by remote sensing technology, highresolution satellite data, playing an important role in surface water monitoring and mapping, which has become the current hot research for water information extraction in recent decades. Therefore, in this paper, we tested and analysed four models to extract water bodies using China's GF-2 HD satellite (GF- 2) image, including Normalized Difference Water Index (NDWI), Modified Shadow Water Index (MSWI), Support Vector Machine (SVM) and Object-Oriented Method (OOM). The results showed applying water extraction models can map surface water with an overall accuracy of 0.8935, 0.9256, 0.9467 and 0.9357, respectively. SVM owns the highest overall accuracy value of 0.9467, followed by OOM. SVM performed significantly better at surface water extraction with kappa coefficients improved by 9.00%, 5.00%, and 2.00%, respectively, which yielded the best results and used to map surfaces water bodies in the study region, while index methods (NDWI and MSWI) are mostly classified into the water and non-water information based on a threshold value, with higher total omission and commission errors at 12.45%, 25.64%, 6.38% and12.87%, respectively. Therefore, we proposed SVM as the best algorithm to identify water body and effectively detect surface water from the GF-2 image. [ABSTRACT FROM AUTHOR]

With the acceleration of urbanization, the urban heat island (UHI) effect has intensified. Urban green space can retard the UHI effect. However, most existing studies have only focused on hot regions, while little attention has been given to cold regions that also have summer heat protection requirements. Furthermore, existing researc has not classified urban green spaces according to the presence or absence of water, which can lead to inaccurate results. This paper takes four cities in cold regions of China as examples and studies the cooling effects of two different types of urban green space. The results indicate that in cold regions of China, green spaces containing water bodies have a stronger cooling effect than those without water. For green spaces without water, the cooling intensity is related to the background temperature and green space areas, while for green spaces containing water bodies, the area of the internal water body is the key influencing factor. Specifically, there is a threshold value of efficiency (TVoE) for the green space areas without water in cold region cities of China, which is approximately 0.52 ha, while there is no TVoE for the green space areas containing water bodies. Additionally, there is a TVoE for the water/land ratio of the green spaces containing water bodies of approximately 0.5. The methods and results of this study can provide a reference for future research and for urban planners and managers designing urban green spaces. [ABSTRACT FROM AUTHOR]

Toppling is a common deformation and failure phenomenon in the reservoir bank slopes of hydropower projects. This paper studies the genesis and evolution of different toppling bodies during water impoundment at the Miaowei Hydropower Station Reservoir on the Lancang River in southwest China. Toppling properties were determined and second failure characteristics analyzed in different reservoir impoundment stages. Different degrees of toppling deformation were primarily affected by the transverse bending stress, while the regional tectonic stress has been shown to have a significant effect on the transverse bending of the rock layers. Combined with the on-site investigation and monitoring results, the failure mechanisms of the different toppling deformation bodies were analyzed. The second failure of the toppling rock mass caused by the reservoir impoundment process is mainly the hydrodynamic splitting along fractures, wave impaction and softening on the slope foot. The transverse bending effect of gravity is transmitted upward through joint misalignment, rotation and slip, accelerating the speed of secondary toppling failure and forming a compression-shear failure along the toppling tension crack. A model to predict the scope and time of failure in the toppling deformation banks under the action of reservoir hydrodynamics was proposed. [ABSTRACT FROM AUTHOR]

Water extraction from remote sensing images can be applied in water resources monitoring, as well as an essential preprocessing for water quality parameter retrieval. China's new generation Gaofen-5 satellite carries a hyperspectral imager named AHSI, which is suitable for water quality monitoring. In this paper, to determine the spectral index most suitable for AHSI data's water extraction, we selected a large lake and a reservoir in China as the study areas, and used corresponding AHSI data for water extraction experiment. In the experiment, NDWI, MNDWI and AWEI were all tested on the AHSI reflectance data, and major water bodies were delineated by implementing the histogram bimodal method on the water index images. Based on analyses with water index images and water extraction results, NDWI is shown to be the optimal index for water extraction of AHSI data among these three widely-used indexes, as it can accurately extract water bodies and also eliminate pixels of water plants or shadows between land and water. In addition, MNDWI can be used on AHSI data since it is most robust in terms of providing a bimodal histogram. AWEI is, however, not suggested to be used for water extraction of the AHSI data. [ABSTRACT FROM AUTHOR]

Artificial and natural water bodies, such as reservoirs, ponds, rivers and lakes, are important components of water-related ecosystems; they are also important indicators of the impact of human activities and climate change on surface water resources. However, due to the global and regional lack of artificial and natural water bodies data sets, understanding of the changes in water-related ecosystems under the dual impact of human activities and climate change is limited and scientific and effective protection and restoration actions are restricted. In this paper, artificial and natural water bodies data sets for China are developed for the years 2000, 2005, 2010, 2015 and 2020 based on satellite remote sensing surface water and artificial water body location sample data sets. The characteristics and causes of the temporal and spatial distributions of the artificial and natural water bodies are also analyzed. The results revealed that the area of artificial and natural water bodies in China shows an overall increasing trend, with obvious differences in spatial distribution during the last 20 years, and that the fluctuation range of artificial water bodies is smaller than that of natural water bodies. This research is critical for understanding the composition and long-term changes in China's surface water system and for supporting and formulating scientific and rational strategies for water-related ecosystem protection and restoration. [ABSTRACT FROM AUTHOR]

Regional processes on land-water-air interface carbon (C) budget and balance that interconnect the land and sea are in fact C neutrality critical processes within the earth system. It is therefore essential to quantitatively analyze synergistic land-water-air interface C transport and C exchange processes to gain a deep understanding of the important role that terrestrial ecosystems play in "missing C sink". This paper systematically analyzes global land-water-air interface C migration processes as well as C budget changes and associated impact mechanisms. It also investigates the important role that these C budgets and C cycling processes play in inland water bodies, respective to C budgets at the land-water-air interface. Moreover, this study reveals the regulatory mechanisms of land-water-air interface C budgets and balances under a background of global climate change. It also quantitatively evaluates the status of China's regional land-sea-air interface C budgets as well as the C sequestration potential of its lake systems. Finally, this study concludes that the explicit quantification of anthropogenic activity impacts on land-water-air interface C transport and exchange processes is of great significance to global C balances and C neutrality. [ABSTRACT FROM AUTHOR]

Rocky desertification is one of the most critical ecological and environmental problems in areas underlain by carbonate rocks globally. Land cover and land use in the region affects large-scale ecosystem processes on a global scale, and many Earth system models rely on accurate land cover information. Therefore, it is important to evaluate current global land cover products and to understand the differences between them, and the findings of these studies can provide guidance to different researchers when using or making land cover products. Whereas there are many studies on the assessment of coarser resolution land cover products, there are few studies on the assessment of higher resolution land cover products (10 m). In order to provide guidance for users of 10 m data, this paper uses the rock deserted southwest region of China as the experimental area. We analyzed the consistency and accuracy of the FROM-GLC, ESA WorldCover 10 and ESRI products using spatial pattern consistency, absolute accuracy assessment of three validation samples, and analyzed their intrinsic relationships among classification systems, classification methods, and validation samples. The results show that (1) the overall accuracy of the FROM-GLC product is the highest, ranging from 49.47 to 62.42%; followed by the overall accuracy of the ESA product, ranging from 45.13 to 64.50%; and the overall accuracy of the ESRI product is the lowest, between 39.03 and 61.94%. (2) The consistency between FROM-GLC and ESA is higher than the consistency between other products, with an area correlation coefficient of 0.94. Analysis of the spatial consistency of the three products shows that the proportion of perfectly consistent areas is low at 44.89%, mainly in areas with low surface heterogeneity and more homogeneous cover types. (3) Across the study area, the main land cover types such as forest and water bodies were the most consistent across the three product species, while the grassland, shrubland, and bareland were lower. All products showed high accuracy in homogeneous areas, with local accuracy varied in other areas, especially at high altitudes in the central and western regions. Therefore, land cover users cannot use these products directly when conducting relevant studies in rocky desertification areas, as their use may introduce serious errors. [ABSTRACT FROM AUTHOR]

This paper attempts to disclose the farmers’ selection bases among different eco-compensation options for the reduction of fertilizer use, a typical non-point source (NPS) of water pollution. Firstly, the reduction methods were divided into six types. Then a survey was carried out on the farmers near two water bodies in south-eastern China’s Zhejiang Province, namely, Qiaodun Reservoir and Siming Lake Reservoir. It was found that when multiple options are available, financial compensation is the most favoured one among farmers, followed by technical learning and policy compensation; the organic fertilizer has the lowest acceptance. Next, a simultaneous bivariate probit model was established to illustrate the effect of each factor on farmers’ selection between intellectual and non-intellectual technical compensations, and between alternative and organic fertilizers. Meanwhile, the farmers’ intentions on policy compensation were examined by the binary probit model. The modelling results show that: the farmers prefer compensation options that complement each other and wish the government could offer integrated compensation plans of these options; the age and education level of house owner, coupled with family income, farmland area, farmland fragmentation, production efficiency and farmers’ willingness to reduce fertilizer application all have important impacts on the selection of compensation means. [ABSTRACT FROM AUTHOR]

Land uses determine water quality within riparian environments to a certain extent and directly affect human health via drinking water. The main objective of this paper is to investigate the influences of land use, both in hydrologic response units (HRUs) and 200-m-wide buffer areas, on surface water quality. The variations and interrelationships between water physicochemical properties and land uses were assessed for better management of water environment. Nitrogen was the dominant nutrient and was significantly correlated with other water quality parameters. In the HRUs and buffer areas, the dominant landscape was grassland and farmland, respectively. Total organic carbon (TOC) and dissolved oxygen (DO) had negative correlation with land use factors; nitrate nitrogen, total nitrogen, total phosphorus, electrical conductivity, and temperature, in contrast, were positively correlated with them. Industrial and residential land was the critical land use for the aquatic environment in the Dan River, indicating that point pollution should receive more attention. Vegetation area had strong regression relationships with TOC and DO. Furthermore, more specific types of land use (subcategory classification) had a greater role in water quality. The land use in buffers can act on the water body more directly and effectively. [ABSTRACT FROM AUTHOR]

In this paper, Yuqiao Reservoir is taken as the research object. The total suspended matter (TSM) produced by the economic development in the upper reaches of the reservoir and its surrounding areas has brought great ecological harm to the safe operation of the reservoir. Satellite remote sensing technology provides a good way to obtain the temporal and spatial variation of TSM in the study area. Two field surveys were carried out in the Yuqiao Reservoir, a total of 44 sampling points collected in the two tests. The spectral data and concentration of TSM were obtained. We developed and validated a robust empirical model to estimate the concentration of TSM in the water of the Yuqiao Reservoir for the first time. The TSM distribution map of the Yuqiao Reservoir in 2013–2018 is retrieved based on Landsat 8 OLI images. This paper analyzes the spatial distribution characteristics of TSM concentration in the Yuqiao Reservoir for several years, as well as the interannual, seasonal, and monthly variation laws and development trends. The results show that the spatial distribution of TSM in Yuqiao Reservoir shows a decreasing trend from the periphery to the center; the interannual changes are mainly as follows: The annual change trend of TSM in Yuqiao Reservoir is not obvious; the seasonal changes are significant: the highest in summer (higher than 40 mg/L), the second in autumn, and the lowest in spring and winter (lower than 15 mg/L); and the monthly changes show regular fluctuations: In a year cycle, the concentration of TSM generally shows an inverted V‐shaped trend; that is, TSM increases gradually from January to August and decreases gradually from August to December. The research results of this paper can be applied to other similar types of land water bodies, which will promote the wide application of Landsat 8 OLI images in the monitoring of TSM in lakes, rivers, and reservoirs in different regions across China, and provide data support for the scientific management of the safe operation of research areas. Practitioner points: The monitoring model of TSM in Yuqiao Reservoir was built for the first time.Temporal and spatial analysis of TSM concentration in Yuqiao Reservoir for the first time.The concentration of TSM is in Yuqiao Reservoir greatly affected by wind speed and precipitation. [ABSTRACT FROM AUTHOR]

Ground penetrating radar (GPR) has been proven to be one of the most promising non-destructive methods that has been widely used in engineering quality inspections and condition assessments of underground structures. This paper reports an application study of GPR that presents a comprehensive survey of the auxiliary shaft of the Anli coal mine in China. During shaft installation, water gushing with a maximum inflow rate of approximately 16.0 m3/h occurred, and thus, it was urgent to determine the distribution range of anomalies and evaluate the lining thickness of the shaft to provide precise technical guidance for later treatments. A GPR grid scan was carried out by towing the antenna along 6 vertical measuring lines and 11 orthogonal circular measuring lines on the shaft surface. The GPR results show that the anomalies experienced by the shaft are voids, uncompacted areas and water bodies. Most anomalies were located in the outer shaft lining and surrounding soil. A vast majority of the shaft lining thickness reach its designed value, with a qualified rate of 91.2% for the inner shaft lining and 89.9% for the outer shaft lining, and the outer shaft lining exhibited inferior smoothness and uniformity. Under the guidance of the GPR results, a grouting treatment was carried out to water seal and strengthen the shaft lining, which, consequently, reduced the water inflow rate by 90%. The favourable grouting effect demonstrates that the GPR method can feasibly and successfully reflect the shaft lining and anomalies in shaft assessments. This engineering practice could serve as a case study reference for investigating any similar underground structure in the future. [ABSTRACT FROM AUTHOR]

Microplastic pollution has attracted more and more people's attention, and it exists widely in our living environment. Microplastics are difficult to be degraded, most of them migrate from the land to the water, and finally deposit in the sediment. They are easy to have a great impact on water bodies and aquatic organisms, and even affect the daily life of human beings. Based on the research literature on microplastics in recent years, this paper reviews the research progress of microplastics in freshwater sediments in China, discusses several commonly used methods of sampling, separation, and detection of microplastics in freshwater sediments, summarizes the distribution characteristics of microplastics in freshwater sediments in China, analyzes the toxicological effects of microplastics, and introduces the degradation methods of microplastics. This study will provide valuable reference for further study of microplastics in freshwater environment in the future. [ABSTRACT FROM AUTHOR]

In the North China Plain, coal mining subsided lakes are surface water bodies that form after the conclusion of coal mining. In China, mining subsided lakes are often transformed into artificial wetland parks for ecological restoration. While many studies have focused on evaluating coal mining subsidence lake ecosystem service value and water pollution, little attention has been paid to changes in ecological regimes and ecological spillover effects before and after the reclamation of mining areas. This paper examines the Pan'an Lake artificial wetland in Jiawang District, Xuzhou, as a case study. Changes in the ecological regime of the mining subsidence area before and after land reclamation and corresponding spatial spillover effect on land prices are assessed based on remote sensing, GIS raster calculations and geostatistical methods. The results show that the ecosystem service value and ecological storage capacity changed significantly after the mining subsided lake was transformed into an artificial wetland and the wetland ecosystem has been developing well with significantly positive spillover effects on surrounding land prices. From 2008 to 2017, service functions of the artificial wetland ecosystem of Pan'an Lake increased by 81.95%, and the system's ecological storage capacity increased from RMB 6,754 yuan/hm2 in 2008 to RMB 12,289 yuan/hm2 in 2017. The average impact of the Pan'an Lake artificial wetland on the spillover effects of surrounding residential land prices was measured at RMB 195.18 yuan/m2, and the total spillover value of planned residential land in the study area was measured at RMB 805,422,100 yuan. The present study can serve as a useful guide for evaluating the economic feasibility of land reclamation planning and ecological restoration in mining subsidence areas. [ABSTRACT FROM AUTHOR]

Large-scale water conservancy projects bear much economic and social significance. However, there is a lack of systematic research on how such projects affect radioactivity levels in regional water bodies. For the first time, the present paper uses data for nearly 10 y at different impoundment levels during construction of the dam to analyze changes in water radioactivity concentration levels in China's Three Gorges region, in order to provide a valuable reference for evaluating the impact of large-scale water conservancy projects on radioactivity concentration levels. Results show that gross α, gross β, U, Th, 226Ra, 40K, 90Sr and 137Cs levels in the water bodies of the Three Gorges region fall within normal limits and annual effective dose for the adults, children and infants are below the WHO recommended reference level of 0.1 mSv per y. The period where the sample was collected and spatial distribution are the main reasons why some radionuclides are not normally distributed. Different water levels during different periods result in large variations in the levels of certain radionuclides, indicating that water levels can have a strong influence on radionuclide levels in reservoir regions. Hence, when evaluating the impact of large-scale water conservancy projects on radioactivity levels, analysis should be carried out on samples collected during different periods in order to make accurate assessments. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper monitors and analyzes the surface water and sediments in the Dongxinkai (DXK) River basin. The analysis shows that the water bodies mainly suffer from aerobic pollution, with chemical oxygen demand (COD) and ammonia nitrogen (NH3-N) being the primary causes of pollution. Considering the main causes of the pollution, the author put forward an integrated pollution control plan for the basin focusing on pollutant interception, source control, and ecological construction. After the treatment, the dissolved oxygen (DO) values at all sampling points were greater than 2 mg/L, the NH3-N values were all smaller than 8 mg/L and the water transparency values were all above 25 cm, indicating that the river is no longer black or odorous. The implementation of the entire plan costs RMB 26.2 × 108 yuan. The research findings shed important new lights on pollution control in other rivers across China. [ABSTRACT FROM AUTHOR]

With the aggravation of global warming and the increasing demand for energy, the development of renewable energy is imminent. Floating photovoltaic (FPV) is a new form of renewable energy generation. However, the impact of FPV on the aquatic environment is still unclear. By long-term empirical monitoring and data analysis, this paper reveals the shading effect of large-scale FPV power station on aquatic environment for the first time. The results show that: (1) Compared with the non-photovoltaic (NP) zone, FPV only significantly reduces the concentration of dissolved oxygen in the photovoltaic (P) zone. (2) The concentration of chlorophyll a , nitrate nitrogen and total phosphorus increase, while pH and ammonia nitrogen decrease. FPV only causes an effect of the same order of magnitude as the initial concentration, and has no significant adverse effects on the nutritional status of the water body at a coverage ratio less than 50%. (3) FPV has a cooling effect on the water body during the daytime and a thermal insulation effect at night, with the most pronounced impact on peak water temperature (T w). The heating and cooling process of T w in P zone usually lags behind the NP zone by 1–3 h. The diurnal fluctuation and vertical difference of T w as well as the stability of water body are reduced under the shading of FPV, alleviating the influence of climate change on T w and water body stratification. (4) If 10% of the water area larger than 1 km2 in China are used to develop FPV, more than 900 million tons of CO 2 emissions can be reduced, and about 5 billion m3 water can be saved, which is significant in the context of climate change. In general, this paper provides a reference for the future aquatic environmental impact assessment of FPV and the formulation of related policies. • The impact of FPV on aquatic environment has been assessed. • The scale effect of FPV and impact of "fish-photovoltaic integration" are revealed. • Spatial-temporal and object specificity of impact on aquatic environment is reviewed. • The responds of FPV to the challenges of global climate change are further discussed. [ABSTRACT FROM AUTHOR]

Plastic pollution is currently one of the environmental pollution issues of global concern, and microplastics (plastics with a size ≤ 5 mm) have also attracted much attention due to their large specific area, higher pollutant adsorption capacity, and higher migration performance. As the population increases and more chemical products are manufactured, the level of microplastic pollution continues to increase. Microplastics discharged from sewage treatment systems will enter the ocean and rivers, so estuary ecosystems are vital to controlling marine microplastics. As the estuary of China's most significant river entering the East China Sea, the Changjiang River Estuary has become one of the typical areas for microplastic research in estuaries. This paper systematically reviews the sources, hazards, and impacts of microplastics in the Changjiang Estuary. Firstly, the research on microplastics in the Changjiang Estuary was analyzed, and we found that the bioaccumulation, removal, and interaction with microorganisms of microplastics have become a new research hotspot. At the same time, the current abundance of microplastics in the surface water of the Changjiang River Estuary is 1.71 ± 3.12 MP/L, which is lower than that of the Changjiang River area and the river farmland in Shanghai, but still higher than the 0.22 ± 0.27 MP/L in the area adjacent to the East China Sea. Microplastics smaller than 1000 μm accounted for 68% of the total, while transparent, white, blue, and black were the primary colors of microplastics in the Changjiang Estuary. In addition, polyethylene and polypropylene are the primary materials of microplastics in the central Changjiang River Estuary and related water bodies, and fibers are the main shape of microplastics. Industry, agriculture, domestic sewage, and air deposition may be the primary sources of microplastics in the Changjiang Estuary. The numerous lakes and water conservancy facilities in the Changjiang River Basin can reduce the number of microplastics reaching the Changjiang Estuary to a certain extent. At the same time, seasonal rainfall and ocean currents will affect the abundance of microplastics in the surface waters of the Changjiang River Estuary. Finally, this paper puts forward relevant suggestions based on the actual situation of the Changjiang River Estuary and the developed microplastic treatment technologies. This article will provide a structured reference for future research on microplastics in the Changjiang Estuary and assist in assessing microplastics' impact on the ecological environment. The Fate of Microplastic Pollution in the Changjiang River Estuary. [Display omitted] • Microplastics' sources, hazards, and impacts in the Yangtze Estuary were reviewed. • Bioaccumulation, removal, and interaction with microorganisms are the hotspots. • The microplastics in the water of the Changjiang mainly exists in the form of fibers. • Source control and establishment of MPs barriers will help to solve MPs pollution. [ABSTRACT FROM AUTHOR]

Climate warming impact on excessive nitrogen (N) load in sediment favours cyanobacterial blooms in eutrophic waters. The nitrate (NO 3 −-N) and ammonium (NH 4 +-N) are two forms of N loads that contribute to algae blooms. However, little attention is paid to the impact of environmental factors on N loads variations at different time scales. This paper used a well-calibrated and validated EFDC model to investigate the temporal patterns and trends of ammonium and nitrate from June 2016 to June 2017. This paper presented the relationship and effects between these variations and environmental factors using data from satellite and reanalysis-based observations obtained for six meteorological parameters. The relationship and effects between these variations and environmental factors were also examined at different timescales (i.e., daily, monthly and seasonal scales). Model calibration results indicated that measured values reasonably matched simulated values. T he validation results revealed that relative error (RE) values were within an acceptable range. The REs of ammonium at East Taihu (S12) and Xu Lake (S23) sampling sites were 55.83% and 57.61%, while that of nitrate was 24.37% (S12) and 41.08%, respectively. The daily analysis of NH 4 +-N and NO 3 −-N variations was 7.318 ± 3.876 (g/m2/day) and 0.0275 ± 0.222 (g/m2/day), respectively. The monthly analysis showed NH 4 +-N and NO 3 −N range from 2.04 to 12.04 (g/m2/day) and 0.0008 to 0.064 (g/m2/day), respectively. The magnitude NH 4 +-N and NO 3 −-N varied and showed distinct inter-monthly variations. , The relationship between sediment fluxes and meteorological parameters showed the magnitude of correlation coefficient (r) and strength of correlation varied significantly. At daily scales, the relationship of NH 4 +-N and NO 3 −-N had a significant positive correlation with all meteorological parameters. At monthly, the correlation coefficient (r) of NH 4 +-N and NO 3 −N were heterogenous. At daily and monthly scales, air temperature and wind speed are the main drivers affecting sediment N loads' dynamics; however, the influence of relative humidity, precipitation, and evaporation on N loads are smaller. The study demonstrates the contribution of meteorological conditions to the magnitude and timing of N loadings variability in water bodies. The findings provide more insight into lake ecosystem protection and environmental remediation. [Display omitted] • The simulated nitrate and ammonium nitrogen were calibrated and validated with field observation data. • The driving factors influencing nitrogen variations were quantified, and their impacts were identified. • Five meteorological variables significantly correlated with Nitrogen variations. • The strength of the correlation coefficient (r) varied across the multiple time scales. • Changes in meteorological conditions affect the timing and magnitude of nitrogen variations in Taihu lake. [ABSTRACT FROM AUTHOR]

Pollution sources release contaminants into water bodies via sewage outfalls (SOs). Using high-resolution images to interpret SOs is laborious and expensive because it needs specific knowledge and must be done by hand. Integrating unmanned aerial vehicles (UAVs) and deep learning technology could assist in constructing an automated effluent SOs detection tool by gaining specialized knowledge. Achieving this objective requires high-quality image datasets for model training and testing. However, there is no satisfactory dataset of SOs. This study presents a high-quality dataset named the images for sewage outfalls objective detection (iSOOD). The 10481 images in iSOOD were captured using UAVs and handheld cameras by individuals from the river basin in China. This study has carefully annotated these images to ensure accuracy and consistency. The iSOOD has undergone technical validation utilizing the YOLOv10 series objective detection model. Our study could provide high-quality SOs datasets for enhancing deep-learning models with UAVs to achieve efficient and intelligent river basin management. [ABSTRACT FROM AUTHOR]

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