Trace Element Contamination in One of the Yangtze Tributaries (Hunan, China)—Source Review and Potential Release from Sediments

Spatio-temporal distribution and leachability of some trace elements (TE) were investigated in sediments of the Xiangjiang River, tributary of the Yangtze River. Based on data collected during 2015–2017, a literature review and geoaccumulation indexes, the pollution level was the highest for Cd, Sb and Hg (Igeo > 3). Over the period reviewed, the TE contamination level displayed almost no temporal variation but an obvious spatial distribution. The most upstream contamination hotspot (Cd > Cr > As, Cu, Pb, Zn > Hg, Sb) was the Songbai section. This hotspot did not spread further downstream. The second hotspot identified was the Zhuzhou–Xiangtan section, impacted by Cd > Hg, Pb, Zn > Cu, with the Zhuzhou area being particularly highly impacted by Pb and Zn. A 30-day leaching experimental protocol under aerobic and anaerobic conditions was carried out to access TE mobility. Low percentages of TE released were calculated, showing that the TE fate mostly depends on the stability of bearing phases under specific physicochemical and microbial conditions. In this case, the studied sediments can be an important sink for these TE. However, some environmental issues have to be considered as some leachate concentrations of contaminants (As, Cr, Cu and U) released into water exceed freshwater aquatic life criteria.

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Interfacial Interactions

Computational Gas-Solids Flows and Reacting Systems - Advances in Chemical and Materials Engineering ◽

10.4018/978-1-61520-651-3.ch004 ◽

2010 ◽

pp. 128-177

Author(s):

Wei Ge ◽

Ning Yang ◽

Wei Wang ◽

Jinghai Li

Keyword(s):

Temporal Distribution ◽

Gravitational Potential Energy ◽

Immersed Boundary ◽

Immersed Boundary Methods ◽

Additional Information ◽

Mesoscale Structures ◽

Computational Fluid Dynamics Cfd ◽

Spatio Temporal ◽

Drag Models ◽

The Stability

The drag interaction between gas and solids not only acts as a driving force for solids in gas-solids flows but also plays as a major role in the dissipation of the energy due to drag losses. This leads to enormous complexities as these drag terms are highly non-linear and multiscale in nature because of the variations in solids spatio-temporal distribution. This chapter provides an overview of this important aspect of the hydrodynamic interactions between the gas and solids and the role of spatio-temporal heterogeneities on the quantification of this drag force. In particular, a model is presented which introduces a mesoscale description into two-fluid models for gas-solids flows. This description is formulated in terms of the stability of gas-solids suspension. The stability condition is, in turn, posed as a minimization problem where the competing factors are the energy consumption required to suspend and transport the solids and their gravitational potential energy. However, the lack of scale-separation leads to many uncertainties in quantifying mesoscale structures. The authors have incorporated this model into computational fluid dynamics (CFD) simulations which have shown improvements over traditional drag models. Fully resolved simulations, such as those mentioned in this chapter and the subject of a later chapter on Immersed Boundary Methods, can be used to obtain additional information about these mesoscale structures. This can be used to formulate better constitutive equations for continuum models.

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Spatio-Temporal Analysis of Rainfall Variability and its Prediction in Al-Qassim Region Using (1987-2017): التحليل المكاني والزماني لتباين التهاطل المطري والتنبؤ به في منطقة القصيم (2017-1987)

Journal of natural sciences, life and applied sciences - مجلة العلوم الطبيعية و الحياتية والتطبيقية ◽

10.26389/ajsrp.l190920 ◽

2020 ◽

Vol 4 (4) ◽

Author(s):

Aljazy Khalid Alturki, Ahmad Abdullah Aldughairi

Keyword(s):

Urban Areas ◽

Rainfall Variability ◽

Temporal Distribution ◽

Temporal Analysis ◽

Seasonal Rainfall ◽

Economic Activities ◽

Systems Software ◽

Distance Weighted ◽

Spatio Temporal ◽

The Stability

This study aimed to analyze the indicators of spatial and temporal distribution of daily, monthly, and seasonal rainfall measurements. It is looking for the possibility of the stability or change of precipitation properties by using the data of the present. Also, it is working with the most important factors that effects on the rainfall, Moreover, many of some statistical methods applied in this study. Using inverted distance weighted Inverse Distance Weighting (IDW) method to generates rain interpolation surface that is tool approves in geographic information systems software. Rain is an important element of many economic activities. Therefore, the importance of predicting the spatial distribution of precipitation that is important from water rain resources. This study presents an analysis of spatiotemporal variation of the daily, monthly and seasonal rainfall in Qassim region, based on data seven weather stations, that is including, Buraidah, Unaizah, Al Rasa, and the General Authority for Meteorology and Environmental Protection, also Prince Nayef Airport Station between (2017-1987) which period included 31 years for the accuracy of the results. The study reached to several recommendations that can be used in geographical fields, whether environmental or human, which are related to water resources and torrents, rainwater drainage projects and urban areas to avoid disasters.

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Endocrine-disrupting compounds in the Xiangjiang River of China: Spatio-temporal distribution, source apportionment, and risk assessment

Ecotoxicology and Environmental Safety ◽

10.1016/j.ecoenv.2018.10.053 ◽

2019 ◽

Vol 167 ◽

pp. 476-484 ◽

Cited By ~ 16

Author(s):

Zhoufei Luo ◽

Yi Tu ◽

Haipu Li ◽

Bo Qiu ◽

Yang Liu ◽

...

Keyword(s):

Risk Assessment ◽

Source Apportionment ◽

Temporal Distribution ◽

Endocrine Disrupting Compounds ◽

Xiangjiang River ◽

Endocrine Disrupting ◽

Spatio Temporal

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Meandering Evolution and Width Variation, a Physics-Statistical Based Modeling Approach

10.29007/qvdj ◽

2018 ◽

Cited By ~ 1

Author(s):

Sergio Lopez Dubon ◽

Daniele Pietro Viero ◽

Stefano Lanzoni

Keyword(s):

Temporal Distribution ◽

Channel Width ◽

Erosion And Deposition ◽

River Bank ◽

Term Evolution ◽

Stress Threshold ◽

Spatio Temporal ◽

Deposition Processes ◽

The Stability

Many models have been proposed to simulate and understand the long-term evolution of meandering rivers. These models analyze the hydraulics of the in-channel flow and the river bank movement (erosion – accretion) process in different ways, but some gap still remain, e.g. the stability of long-term simulations when width variations are accounted for. Here we proposed a physics-statistical based approach to simulate the river bank evolution, that erosion and deposition processes act independently, with a specific shear stress threshold for each of them. In addition, we link the width evolution with a parametric probability distribution (PPD) based on a mean characteristic channel width. We are thus able to obtaining stable long-term simulations with realistic and reasonable spatio-temporal distribution of the along channel width.

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