Pub Date : 2024-09-26DOI: 10.1016/j.ijsrc.2024.09.004
Hamza Beddaa , Saannibe Ciryle Somé , Amor Ben Fraj , Coryse Coudray , Emmanuel Branche , Amaury Cudeville
Hydroelectric dams play a crucial role in power generation, water storage, and irrigation. However, their continuous operation has led to sediment accumulation, thereby reducing the water storage capacity and impacting the facility's life span. The aim of the current study is to assess the reuse potential of dredged fine sediment in the composition of road subgrades. Nine types of sediment from diverse hydroelectric dams are analyzed for their chemical, environmental, physical, and geotechnical properties. These sediments then were treated with quicklime and a slag-based hydraulic road binder (3% and 6%, respectively). The current investigation involves evaluating: Proctor parameters, the immediate bearing index, treatment ability, and the mechanical properties of the treated sediment. The results reveal that the properties of treated sediment differ from one mixture to another, thus, indicating that some mixtures meet the criteria outlined in the French Roadworks Guide, by virtue of their clay and organic matter contents. Moreover, the current study explores the impact of incorporating recycled concrete sand (RCS) as a granular corrector to enhance the reuse potential of the sediment in road subgrades. The current findings indicate that adding RCS significantly improves mixture properties, particularly mechanical characteristics, by reaching 1 MPa before 7 days of curing. These promising outcomes pave the way for more advanced road construction practices in ensuring environmental compliance and promoting an eco-friendly reuse of sediment.
{"title":"Potential reuse of fine sediment from hydroelectric dams and recycled concrete sand in road subgrades","authors":"Hamza Beddaa , Saannibe Ciryle Somé , Amor Ben Fraj , Coryse Coudray , Emmanuel Branche , Amaury Cudeville","doi":"10.1016/j.ijsrc.2024.09.004","DOIUrl":"10.1016/j.ijsrc.2024.09.004","url":null,"abstract":"<div><div>Hydroelectric dams play a crucial role in power generation, water storage, and irrigation. However, their continuous operation has led to sediment accumulation, thereby reducing the water storage capacity and impacting the facility's life span. The aim of the current study is to assess the reuse potential of dredged fine sediment in the composition of road subgrades. Nine types of sediment from diverse hydroelectric dams are analyzed for their chemical, environmental, physical, and geotechnical properties. These sediments then were treated with quicklime and a slag-based hydraulic road binder (3% and 6%, respectively). The current investigation involves evaluating: Proctor parameters, the immediate bearing index, treatment ability, and the mechanical properties of the treated sediment. The results reveal that the properties of treated sediment differ from one mixture to another, thus, indicating that some mixtures meet the criteria outlined in the French Roadworks Guide, by virtue of their clay and organic matter contents. Moreover, the current study explores the impact of incorporating recycled concrete sand (RCS) as a granular corrector to enhance the reuse potential of the sediment in road subgrades. The current findings indicate that adding RCS significantly improves mixture properties, particularly mechanical characteristics, by reaching 1 MPa before 7 days of curing. These promising outcomes pave the way for more advanced road construction practices in ensuring environmental compliance and promoting an eco-friendly reuse of sediment.</div></div>","PeriodicalId":50290,"journal":{"name":"International Journal of Sediment Research","volume":"39 6","pages":"Pages 971-983"},"PeriodicalIF":3.5,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142662610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-26DOI: 10.1016/j.ijsrc.2024.09.006
Jiyuan You , Xiaohu Zhou , Yiyao Yang , Shanshan Song , Yiqun Liu , Zhengzhong Liang , Yunyun Bai
The Triassic lacustrine organic-rich shale (LORS) in Member 7 of the Yanchang Formation (Carnian stage) in the southern Ordos Basin is relatively well developed. Additionally, its organic matter abundance, lake biomass and biodiversity, exceed the maximum values of the other strata deposited during the same period. Apatite is one of the most important minerals and is closely related to biological activities. However, the types and genesis of the continental sedimentary apatite and its significance to shale oil are not clear. Here, the stratigraphy, petrology, and sedimentology of the phosphorus-bearing rock series in the Ma Quan section are studied and its sedimentary environment and phosphorus formation are discussed. The current research shows that apatite in the study area can be divided into three categories: collophanite, bone fossils, and spherical microfossils. These three types of biogenic “phosphorus” products provide effective records of the transformation of the biological substances into sedimentary organic matter. There are two main formation mechanisms: the direct action of organisms and the interaction between the organisms. Bone fossils and spherical microfossils are formed by the direct action of organisms, while collophanite is formed by the indirect action of organisms. The phosphatization methods of the organisms mainly include “coating”, “replacement”, and “filling”, and the presence of a ubiquitous phosphate filler potentially reflects a sufficient phosphate supply. Apatite also is highly important for the development of organic matter in oil shale. First, it changes the productivity conditions. Second, the apatite in the shell of spherical microfossils has a certain protective effect on the organic matter in the inner cavity. In the current study, the geological processes of collophanite deposition and mineralization are explained, an important basis for prospecting phosphate resources is provided, and a new field for the study of the organic matter enrichment mechanism of source rocks is established. At the same time, the process of lake biogenic phosphorus formation provides evidence from the continental deposits in the eastern margin of the Tethys region for exploring deep global changes.
{"title":"Biogenic “phosphorus” effect of terrestrial lakes and its significance to oil shale during the Carnian period in the late Triassic","authors":"Jiyuan You , Xiaohu Zhou , Yiyao Yang , Shanshan Song , Yiqun Liu , Zhengzhong Liang , Yunyun Bai","doi":"10.1016/j.ijsrc.2024.09.006","DOIUrl":"10.1016/j.ijsrc.2024.09.006","url":null,"abstract":"<div><div>The Triassic lacustrine organic-rich shale (LORS) in Member 7 of the Yanchang Formation (Carnian stage) in the southern Ordos Basin is relatively well developed. Additionally, its organic matter abundance, lake biomass and biodiversity, exceed the maximum values of the other strata deposited during the same period. Apatite is one of the most important minerals and is closely related to biological activities. However, the types and genesis of the continental sedimentary apatite and its significance to shale oil are not clear. Here, the stratigraphy, petrology, and sedimentology of the phosphorus-bearing rock series in the Ma Quan section are studied and its sedimentary environment and phosphorus formation are discussed. The current research shows that apatite in the study area can be divided into three categories: collophanite, bone fossils, and spherical microfossils. These three types of biogenic “phosphorus” products provide effective records of the transformation of the biological substances into sedimentary organic matter. There are two main formation mechanisms: the direct action of organisms and the interaction between the organisms. Bone fossils and spherical microfossils are formed by the direct action of organisms, while collophanite is formed by the indirect action of organisms. The phosphatization methods of the organisms mainly include “coating”, “replacement”, and “filling”, and the presence of a ubiquitous phosphate filler potentially reflects a sufficient phosphate supply. Apatite also is highly important for the development of organic matter in oil shale. First, it changes the productivity conditions. Second, the apatite in the shell of spherical microfossils has a certain protective effect on the organic matter in the inner cavity. In the current study, the geological processes of collophanite deposition and mineralization are explained, an important basis for prospecting phosphate resources is provided, and a new field for the study of the organic matter enrichment mechanism of source rocks is established. At the same time, the process of lake biogenic phosphorus formation provides evidence from the continental deposits in the eastern margin of the Tethys region for exploring deep global changes.</div></div>","PeriodicalId":50290,"journal":{"name":"International Journal of Sediment Research","volume":"39 6","pages":"Pages 960-970"},"PeriodicalIF":3.5,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142662599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-26DOI: 10.1016/j.ijsrc.2024.09.005
Sándor Baranya
While bedload transport is crucial to river morphodynamics, quantifying it in large rivers, such as the Danube, poses significant challenges. The current study focuses on the gravel-dominated section of the Danube River in Hungary, where multiple methods have been concurrently applied to evaluate bedload transport. In a representative cross section of the river, the following methods were applied: (i) point-wise direct physical sampling using a BfG-type pressure difference sampler, quality controlled with a video camera mounted on the sampler; (ii) indirect acoustic-based analysis with an Acoustic Doppler Current Profiler (ADCP), evaluating the Bottom Tracking signal; and (iii) indirect acoustic and imaging-based method utilizing Acoustic Mapping Velocimetry (AMV). The ADCP method is calibrated using results from the physical sampling, while the AMV method relies on bedform tracking and is entirely independent from the two other techniques. The results from a series of measurement campaigns, covering a wide range of flow regimes, suggest a robust bedload rating curve for the study section, enabling the estimation of bedload yields and its relation to morphological changes. In addition, the applicability conditions of the implemented methods are discussed.
{"title":"Quantification of bedload transport in the Hungarian Danube using multiple analysis methods","authors":"Sándor Baranya","doi":"10.1016/j.ijsrc.2024.09.005","DOIUrl":"10.1016/j.ijsrc.2024.09.005","url":null,"abstract":"<div><div>While bedload transport is crucial to river morphodynamics, quantifying it in large rivers, such as the Danube, poses significant challenges. The current study focuses on the gravel-dominated section of the Danube River in Hungary, where multiple methods have been concurrently applied to evaluate bedload transport. In a representative cross section of the river, the following methods were applied: (i) point-wise direct physical sampling using a BfG-type pressure difference sampler, quality controlled with a video camera mounted on the sampler; (ii) indirect acoustic-based analysis with an Acoustic Doppler Current Profiler (ADCP), evaluating the Bottom Tracking signal; and (iii) indirect acoustic and imaging-based method utilizing Acoustic Mapping Velocimetry (AMV). The ADCP method is calibrated using results from the physical sampling, while the AMV method relies on bedform tracking and is entirely independent from the two other techniques. The results from a series of measurement campaigns, covering a wide range of flow regimes, suggest a robust bedload rating curve for the study section, enabling the estimation of bedload yields and its relation to morphological changes. In addition, the applicability conditions of the implemented methods are discussed.</div></div>","PeriodicalId":50290,"journal":{"name":"International Journal of Sediment Research","volume":"39 6","pages":"Pages 1015-1026"},"PeriodicalIF":3.5,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142662572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-20DOI: 10.1016/j.ijsrc.2024.08.004
Li He , Hang Yin , Yongkang Wu , Wei Sun , Guoping Zhang
The response of suspended tenuous clay-polysaccharide flocs to hydrodynamic shearing was investigated in the laboratory via particle size analyses to understand the molecular-scale interactions between clay minerals and polysaccharides and their hydrodynamic behavior such as size kinetics, re-flocculation/breakdown, and shear strengths of the hybrid flocs. While the studied suspensions had a fixed clay concentration of 0.4 g/L, an array of other parameters was varied to reflect the complexity of clay-polysaccharide systems, including four types of clay minerals with varying layer charges and swellability (i.e., kaolinite, illite, and sodium- (Na-) and calcium- (Ca-) montmorillonites), two exopolymers of dissimilar polarities (i.e., xanthan and guar), six polysaccharide (P) to clay (C) weight ratios (i.e., P/C = 0, 1, 2, 5, 10, and 20 wt%), and three hydrodynamic shearing rates of 187, 429, and 1,100 1/s (i.e., corresponding to laminar, transitional, and turbulent flows, respectively). Results show that the clay-polysaccharide floc sizes are sensitive to the shear stress and also vary with different clay-polysaccharide systems. Four discrete particle groups were identified by statistical analyses, consisting of primary particle (PP), flocculi (FL), microfloc (MiF), and macrofloc (MaF), which exhibit distinct stabilities to shearing. The MaF is much weaker than MiF and can easily breakdown, as indicated by the decrease in MaF fraction with increasing shearing, while the MiF is the dominant particle group in transitional and turbulent flows. The fractions of PP and FL generally increase with shearing rate. Based on floc survivability in different flow conditions, the MaF's upper and lower bound shear strengths were estimated to be 0.95 and 0.17 Pa, respectively. The strongest MaF with a maximum shear strength of 0.95 Pa is formed in the clay-guar suspensions at a P/C of 10 wt%. Anionic xanthan only forms flocs with kaolinite with little surface charges, but cannot induce clay-polysaccharide flocs for illite and Ca/Na-montmorillonite with negative surface charges due to electrostatic repulsion. In contrast, neutral guar generates flocs with all 4 clay minerals due to the formation of hydrogen bonds, and MaF compounds usually are absent in turbulent flow (except kaolinite with a small fraction of MaF). These results further demonstrate the essential role of polysaccharide's polarity in dictating the flocculation dynamics, and, hence, sediment transport behavior. Practical implications of the findings are discussed in terms of the emerging technological applications of clay-polymer systems as well as the transport and modeling of natural aquatic cohesive sediment in biofilm-bearing waters.
{"title":"Response of tenuous clay-polysaccharide flocs to hydrodynamic shearing","authors":"Li He , Hang Yin , Yongkang Wu , Wei Sun , Guoping Zhang","doi":"10.1016/j.ijsrc.2024.08.004","DOIUrl":"10.1016/j.ijsrc.2024.08.004","url":null,"abstract":"<div><div>The response of suspended tenuous clay-polysaccharide flocs to hydrodynamic shearing was investigated in the laboratory via particle size analyses to understand the molecular-scale interactions between clay minerals and polysaccharides and their hydrodynamic behavior such as size kinetics, re-flocculation/breakdown, and shear strengths of the hybrid flocs. While the studied suspensions had a fixed clay concentration of 0.4 g/L, an array of other parameters was varied to reflect the complexity of clay-polysaccharide systems, including four types of clay minerals with varying layer charges and swellability (i.e., kaolinite, illite, and sodium- (Na-) and calcium- (Ca-) montmorillonites), two exopolymers of dissimilar polarities (i.e., xanthan and guar), six polysaccharide (<em>P</em>) to clay (<em>C</em>) weight ratios (i.e., <em>P</em>/<em>C</em> = 0, 1, 2, 5, 10, and 20 wt%), and three hydrodynamic shearing rates of 187, 429, and 1,100 1/s (i.e., corresponding to laminar, transitional, and turbulent flows, respectively). Results show that the clay-polysaccharide floc sizes are sensitive to the shear stress and also vary with different clay-polysaccharide systems. Four discrete particle groups were identified by statistical analyses, consisting of primary particle (PP), flocculi (FL), microfloc (MiF), and macrofloc (MaF), which exhibit distinct stabilities to shearing. The MaF is much weaker than MiF and can easily breakdown, as indicated by the decrease in MaF fraction with increasing shearing, while the MiF is the dominant particle group in transitional and turbulent flows. The fractions of PP and FL generally increase with shearing rate. Based on floc survivability in different flow conditions, the MaF's upper and lower bound shear strengths were estimated to be 0.95 and 0.17 Pa, respectively. The strongest MaF with a maximum shear strength of 0.95 Pa is formed in the clay-guar suspensions at a <em>P</em>/<em>C</em> of 10 wt%. Anionic xanthan only forms flocs with kaolinite with little surface charges, but cannot induce clay-polysaccharide flocs for illite and Ca/Na-montmorillonite with negative surface charges due to electrostatic repulsion. In contrast, neutral guar generates flocs with all 4 clay minerals due to the formation of hydrogen bonds, and MaF compounds usually are absent in turbulent flow (except kaolinite with a small fraction of MaF). These results further demonstrate the essential role of polysaccharide's polarity in dictating the flocculation dynamics, and, hence, sediment transport behavior. Practical implications of the findings are discussed in terms of the emerging technological applications of clay-polymer systems as well as the transport and modeling of natural aquatic cohesive sediment in biofilm-bearing waters.</div></div>","PeriodicalId":50290,"journal":{"name":"International Journal of Sediment Research","volume":"39 6","pages":"Pages 984-997"},"PeriodicalIF":3.5,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142662560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The ancient city of Phaselis, which is located along gravel, coarse sandy, and sandy beaches, is a popular area visited by thousands of domestic and foreign tourists every year, and has been selected as the study area. Sediment samples collected from 57 different locations in the ancient city of Phaselis were analyzed using an X-ray fluorescence (XRF) spectrometer, and the major, trace, and rare earth element contents of the samples were revealed. The heavy metals arsenic (As), cobalt (Co), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), tin (Sn), stronsium (Sr), and zinc (Zn) were used in the pollution index calculations. Distribution maps revealed that heavy metal concentrations reached higher levels, especially in the eastern part of the study area. Therefore, it is recommended to plant rooted macrophytes that can absorb the heavy metals Cr and Ni and perform phytoremediation of the sediment in the region.
法塞里斯古城位于砾石滩、粗沙滩和沙滩沿岸，是每年有成千上万国内外游客到访的热门地区，因此被选为研究区域。研究人员使用 X 射线荧光光谱仪（XRF）对从法塞利斯古城 57 个不同地点采集的沉积物样本进行了分析，揭示了样本中主要元素、痕量元素和稀土元素的含量。重金属砷（As）、钴（Co）、铬（Cr）、铜（Cu）、镍（Ni）、铅（Pb）、锡（Sn）、锶（Sr）和锌（Zn）被用于污染指数计算。分布图显示，重金属浓度达到较高水平，尤其是在研究区域的东部。因此，建议在该地区种植能吸收重金属铬和镍的根系大型植物，对沉积物进行植物修复。
{"title":"Source identification of heavy metal contamination in beach sediments of the ancient city of Phaselis in Antalya, Türkiye","authors":"Ozge Ozer Atakoglu , Emirhan Berberoglu , Fusun Yalcin , Serife Gokaydin , Ebru Akkopru , Mustafa Gurhan Yalcin","doi":"10.1016/j.ijsrc.2024.09.003","DOIUrl":"10.1016/j.ijsrc.2024.09.003","url":null,"abstract":"<div><div>The ancient city of Phaselis, which is located along gravel, coarse sandy, and sandy beaches, is a popular area visited by thousands of domestic and foreign tourists every year, and has been selected as the study area. Sediment samples collected from 57 different locations in the ancient city of Phaselis were analyzed using an X-ray fluorescence (XRF) spectrometer, and the major, trace, and rare earth element contents of the samples were revealed. The heavy metals arsenic (As), cobalt (Co), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), tin (Sn), stronsium (Sr), and zinc (Zn) were used in the pollution index calculations. Distribution maps revealed that heavy metal concentrations reached higher levels, especially in the eastern part of the study area. Therefore, it is recommended to plant rooted macrophytes that can absorb the heavy metals Cr and Ni and perform phytoremediation of the sediment in the region.</div></div>","PeriodicalId":50290,"journal":{"name":"International Journal of Sediment Research","volume":"39 6","pages":"Pages 942-959"},"PeriodicalIF":3.5,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142662600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-06DOI: 10.1016/j.ijsrc.2024.09.001
Enqi Yang , Qingzheng Wang , Zepeng Zhang , Wenyan Shao , Haiping Luo , Xiong Xiao , Fei Ni , Jimin Mi , Xiazhong Sun , Qingyu Guan
Heavy metals can easily accumulate in soil and river sediment due to their non-degradability, which seriously endangers the balance of the ecosystem and human health. Thus, research on heavy metals in soil-river composite ecosystems has great significance for risk mitigation. As a seasonal river in a semi-arid region (Yuzhong county) in northwest China, the Wanchuan River supports nearly 500,000 people, but has been polluted by the heavy metals from industrial wastes and sewage discharges. To protect precious water resources and soil ecosystems, it is urgent to do heavy metal research in the Wanchuan River basin. Towards this end, the current study collected samples of soil and river sediment in this basin, and analyzed the distribution characteristics, health risks, and pollution sources of heavy metals, based on the pollution index evaluation method, health risk assessment, a geostatistical model, and the positive matrix factorization (PMF) model. The research results show that the contents of heavy metals in soil and river sediment were equivalent. However, contamination levels of heavy metals in stream sediment fell below that in soil. The results from the PMF model pointed out that natural sources contributed remarkably to the contents of heavy metals in soil, while industrial sources had the highest contribution to the contents of heavy metals in river sediment. According to the health risk assessment, among all selected metals, Cr brought about the highest carcinogenic risk, while As generated the highest non-carcinogenic risk. Source-oriented health risk assessment showed that natural sources (37%) and agricultural sources (50%), respectively, contributed most to the non-carcinogenic risks and carcinogenic risks induced by soil metals. Industrial sources contributed most both to the non-carcinogenic risks (46%) and carcinogenic risks (37%) induced by river sediment metals. The current research may offer theoretical bases for heavy metal pollution treatment in the soil-river continuum.
{"title":"Source-oriented health risk assessment of heavy metals in a soil-river continuum in northwest China","authors":"Enqi Yang , Qingzheng Wang , Zepeng Zhang , Wenyan Shao , Haiping Luo , Xiong Xiao , Fei Ni , Jimin Mi , Xiazhong Sun , Qingyu Guan","doi":"10.1016/j.ijsrc.2024.09.001","DOIUrl":"10.1016/j.ijsrc.2024.09.001","url":null,"abstract":"<div><div>Heavy metals can easily accumulate in soil and river sediment due to their non-degradability, which seriously endangers the balance of the ecosystem and human health. Thus, research on heavy metals in soil-river composite ecosystems has great significance for risk mitigation. As a seasonal river in a semi-arid region (Yuzhong county) in northwest China, the Wanchuan River supports nearly 500,000 people, but has been polluted by the heavy metals from industrial wastes and sewage discharges. To protect precious water resources and soil ecosystems, it is urgent to do heavy metal research in the Wanchuan River basin. Towards this end, the current study collected samples of soil and river sediment in this basin, and analyzed the distribution characteristics, health risks, and pollution sources of heavy metals, based on the pollution index evaluation method, health risk assessment, a geostatistical model, and the positive matrix factorization (PMF) model. The research results show that the contents of heavy metals in soil and river sediment were equivalent. However, contamination levels of heavy metals in stream sediment fell below that in soil. The results from the PMF model pointed out that natural sources contributed remarkably to the contents of heavy metals in soil, while industrial sources had the highest contribution to the contents of heavy metals in river sediment. According to the health risk assessment, among all selected metals, Cr brought about the highest carcinogenic risk, while As generated the highest non-carcinogenic risk. Source-oriented health risk assessment showed that natural sources (37%) and agricultural sources (50%), respectively, contributed most to the non-carcinogenic risks and carcinogenic risks induced by soil metals. Industrial sources contributed most both to the non-carcinogenic risks (46%) and carcinogenic risks (37%) induced by river sediment metals. The current research may offer theoretical bases for heavy metal pollution treatment in the soil-river continuum.</div></div>","PeriodicalId":50290,"journal":{"name":"International Journal of Sediment Research","volume":"39 6","pages":"Pages 916-928"},"PeriodicalIF":3.5,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142247354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-03DOI: 10.1016/j.ijsrc.2024.09.002
Enhui Jiang , Junhua Li , Yongtao Cao , Yanhui Liu , Yuanjian Wang , Qiang Wan , Li Pan
River-bottom tearing scour (RBTS) in natural rivers refers to the incipient motion and transport processes of clay blocks formed by fine cohesive sediment after deposition and consolidation in riverbeds. The RBTS phenomenon can lead to significant channel erosion and changes in river planview morphology, and has, thus, attracted the attention of hydrologists and engineers. In the study, a new determination measure (K) for the occurrence of a RBTS event is derived based on the theoretical expression for the critical incipient velocity of the clay block, , which is a combination of the coefficients of the velocity (i.e., is a local velocity coefficient), lift force (i.e., CL is the lift coefficient), and clay block size (i.e., is the ratio of block thickness to length). Furthermore, to explain river behavior during a RBTS event, the Fugu, Xiaobeiganliu, and Weihe river reaches in the Middle Yellow River (MYR) were selected as study areas. Analysis of hydrological data from 1950 to 2023 in the examined reaches implies that a single discharge or sediment threshold cannot predict the occurrence of RBTS. The cross-sectional erosion and deposition volume (CEDV) and the migration intensity of the channel thalweg (MI) also were calculated at the section and reach scales for the examined reaches during the RBTS events. It was observed that RBTS typically causes significant channel erosion originating from the most upstream portion of the study reach with CEDV values ranging from 61 to 6034 m2, while MI values during the RBTS events were close to the multi-year average for the study reach. Finally, a flume experiment simulating RBTS was done to discuss and verify the threshold value of K. Field survey and experimental results indicated that RBTS occurs if K > 0.5, thus, providing theoretical support for the prediction and prevention of RBTS.
{"title":"Defining and characterizing the phenomenon of river-bottom tearing scour (RBTS): A case study of the Middle Yellow River","authors":"Enhui Jiang , Junhua Li , Yongtao Cao , Yanhui Liu , Yuanjian Wang , Qiang Wan , Li Pan","doi":"10.1016/j.ijsrc.2024.09.002","DOIUrl":"10.1016/j.ijsrc.2024.09.002","url":null,"abstract":"<div><div>River-bottom tearing scour (RBTS) in natural rivers refers to the incipient motion and transport processes of clay blocks formed by fine cohesive sediment after deposition and consolidation in riverbeds. The RBTS phenomenon can lead to significant channel erosion and changes in river planview morphology, and has, thus, attracted the attention of hydrologists and engineers. In the study, a new determination measure (<em>K</em>) for the occurrence of a RBTS event is derived based on the theoretical expression for the critical incipient velocity of the clay block, <span><math><mrow><mi>K</mi><mo>=</mo><msup><mrow><mspace></mspace><mi>α</mi></mrow><mn>2</mn></msup><mrow><mo>(</mo><mrow><msub><mi>C</mi><mi>L</mi></msub><mo>+</mo><mn>2</mn><msubsup><mi>λ</mi><mn>2</mn><mn>2</mn></msubsup></mrow><mo>)</mo></mrow></mrow></math></span>, which is a combination of the coefficients of the velocity (i.e., <span><math><mrow><mi>α</mi></mrow></math></span> is a local velocity coefficient), lift force (i.e., <em>C</em><sub>L</sub> is the lift coefficient), and clay block size (i.e., <span><math><mrow><msub><mi>λ</mi><mn>2</mn></msub></mrow></math></span> is the ratio of block thickness to length). Furthermore, to explain river behavior during a RBTS event, the Fugu, Xiaobeiganliu, and Weihe river reaches in the Middle Yellow River (MYR) were selected as study areas. Analysis of hydrological data from 1950 to 2023 in the examined reaches implies that a single discharge or sediment threshold cannot predict the occurrence of RBTS. The cross-sectional erosion and deposition volume (CEDV) and the migration intensity of the channel thalweg (MI) also were calculated at the section and reach scales for the examined reaches during the RBTS events. It was observed that RBTS typically causes significant channel erosion originating from the most upstream portion of the study reach with CEDV values ranging from 61 to 6034 m<sup>2</sup>, while MI values during the RBTS events were close to the multi-year average for the study reach. Finally, a flume experiment simulating RBTS was done to discuss and verify the threshold value of <em>K</em>. Field survey and experimental results indicated that RBTS occurs if <em>K</em> > 0.5, thus, providing theoretical support for the prediction and prevention of RBTS.</div></div>","PeriodicalId":50290,"journal":{"name":"International Journal of Sediment Research","volume":"39 6","pages":"Pages 929-941"},"PeriodicalIF":3.5,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142247385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Soil erosion is considered one of the most prevalent natural hazards in semiarid regions, leading to the instability of ecosystems and human life. The main purpose of this research was to investigate and analyze soil erosion susceptibility maps in the Medjerda basin in northern Africa. This study utilizes four ensemble models based on the analytical hierarchy process (AHP) multicriteria decision-making analysis, namely, deep learning neural network AHP (DLNN-AHP), frequency ratio AHP (FR-AHP), Monte Carlo AHP (MC-AHP), and fuzzy AHP (F-AHP). Eight predictor variables were considered as inputs to the model, namely, the slope degree, digital elevation model (DEM), topographic wetness index (TWI), distance to river (DFR), distance to road (DFRD), normalized difference vegetation index (NDVI), rainfall erosivity (R), factor and soil erodibility factor (K). Soil erosion inventory maps were developed from field surveys and satellite images. The dataset was randomly divided into 70% for training and 30% for testing. The performances of the utilized models were compared using a receiver operating characteristic (ROC) curve. The results highlighted that all the models utilized exhibited good performance, with DLNN-AHP (93.1%) exhibiting slight superiority, followed by FR-AHP (90.9%), F-AHP (88.9%), and MC-AHP (88.5%). Among the influencing factors, the distance to the river and rainfall erosivity had the most significant impacts on the incidence of soil erosion. Moreover, the current findings revealed that 38.3% of the study area is extremely highly susceptible to soil erosion. The results of this study can aid in developing decision-support tools for planners and managers aiming to mitigate the adverse effects of soil erosion.
{"title":"Soil erosion susceptibility prediction using ensemble hybrid models with multicriteria decision-making analysis: Case study of the Medjerda basin, northern Africa","authors":"Asma Bouamrane , Hamouda Boutaghane , Ali Bouamrane , Noura Dahri , Habib Abida , Mohamed Saber , Sameh A. Kantoush , Tetsuya Sumi","doi":"10.1016/j.ijsrc.2024.08.003","DOIUrl":"10.1016/j.ijsrc.2024.08.003","url":null,"abstract":"<div><div>Soil erosion is considered one of the most prevalent natural hazards in semiarid regions, leading to the instability of ecosystems and human life. The main purpose of this research was to investigate and analyze soil erosion susceptibility maps in the Medjerda basin in northern Africa. This study utilizes four ensemble models based on the analytical hierarchy process (AHP) multicriteria decision-making analysis, namely, deep learning neural network AHP (DLNN-AHP), frequency ratio AHP (FR-AHP), Monte Carlo AHP (MC-AHP), and fuzzy AHP (F-AHP). Eight predictor variables were considered as inputs to the model, namely, the slope degree, digital elevation model (DEM), topographic wetness index (TWI), distance to river (DFR), distance to road (DFRD), normalized difference vegetation index (NDVI), rainfall erosivity (<em>R</em>), factor and soil erodibility factor (<em>K</em>). Soil erosion inventory maps were developed from field surveys and satellite images. The dataset was randomly divided into 70% for training and 30% for testing. The performances of the utilized models were compared using a receiver operating characteristic (ROC) curve. The results highlighted that all the models utilized exhibited good performance, with DLNN-AHP (93.1%) exhibiting slight superiority, followed by FR-AHP (90.9%), F-AHP (88.9%), and MC-AHP (88.5%). Among the influencing factors, the distance to the river and rainfall erosivity had the most significant impacts on the incidence of soil erosion. Moreover, the current findings revealed that 38.3% of the study area is extremely highly susceptible to soil erosion. The results of this study can aid in developing decision-support tools for planners and managers aiming to mitigate the adverse effects of soil erosion.</div></div>","PeriodicalId":50290,"journal":{"name":"International Journal of Sediment Research","volume":"39 6","pages":"Pages 998-1014"},"PeriodicalIF":3.5,"publicationDate":"2024-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142186086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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