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Hydro-geochemistry of groundwater and surface water in Dschang town(West Cameroon): Alkali and alkaline-earth elements ascertain lithological and anthropogenic constraints 
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下载免费PDF全文 Yemeli Elida Joelle Temgoua Emile Kengni Lucas Ambrosi Jean-Paul Momo-nouazi Mathieu Silatsa-Tedou Francis Brice Wamba Franck Robean Tchakam-Kamtchueng Brice 《地下水科学与工程》2021,9(3):212-224
This study focuses on the sources of alkali and alkaline-earth elements based on the geochemistry of groundwater and surface water in Dschang concerning environmental and anthropogenic constraints. A comprehensive set of 50 samples from groundwater and surface water were analyzed by ICPMS and processed by spatial interpolation in a GIS environment. The results highlight a geochemical anomaly at the center of the densely inhabited area subject to a profusion of open dumps discharges. This anomaly with the highest spatial contents of Be(Cs, Rb, Mg) suggests an anthropogenic source that demarcates with the lowest alkali and alkaline-earth elements on the peripheral area of Dschang. Other findings include lithological constraints with volcanic rocks being the main source compared to granitoid.The study points out good correlations between Be, Cs, Rb and Mg spatial distributions and physicochemical parameters of waters(K, EC, TDS), and inversely with the lowest p H. p H is established as the most functioning physico-chemical constraint of alkali and alkaline-earth mobility in Dschang. The p H lowest values within the geochemical anomaly also highlight the impact of human activities on water acidity, which later enhance elements mobility and enrichment. Despite low elements contents relative to WHO standards, our findings point out an example of anthropogenic impact on water geochemistry linked to solid waste pollution; it also demonstrates significant anthropogenic changes of environmental physicochemical parameters of prime importance in the mobility and distribution of elements in the study area.Similar assessments should be extended in major towns in Cameroon. 相似文献
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In a recent paper, Nof et al. (J Paleolimnol 35:417–439, 2006) suggest a physical mechanism which could account for the formation
of ice on Lake Kinneret (Sea of Galilee) in northern Israel. Based on the sea surface temperature record of sediment cores
from the Mediterranean Sea the authors argue that centennial-scale cold events had the potential to trigger local ‘springs
ice’ formation on the lake in the past. Here, we demonstrate that a closer inspection of the paleoceanographic record in combination
with correlation and regression analyses of meteorological data provides no evidence for such cold events in the lake region
during the last 10,000 years. Thus, the formation of ‘springs ice’ on Lake Kinneret was unlikely at least since the beginning
of the Neolithic. 相似文献
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Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in sediments from Hong Kong 总被引：4，自引：0，他引：4
Müller JF Gaus C Prange JA Päpke O Poon KF Lam MH Lam PK 《Marine pollution bulletin》2002,45(1-12):372-378
Concentrations of 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were determined in 14 sediment samples collected from four sites in the Mai Po Marshes Nature Reserve (within a RAMSAR Site) and from another six sites in Victoria Harbour and along the Hong Kong coastline. Elevated levels of PCDDs, and particularly OCDD, were detectable in all samples collected from the Mai Po Marshes and five of the six sites. In contrast to PCDDs, PCDFs were mainly found in sediment samples collected from industrial areas (Kwun Tong and To Kwa Wan) in Victoria Harbour. PCDD/F levels and congener profiles in the samples from the Mai Po Marshes Nature Reserve in particular show strong similarities to those reported in studies which have attributed similar elevated PCDD concentrations to nonanthropogenic PCDD sources. 相似文献
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Nowadays,the preservation of natural resources,the reuse,and the recycling of waste and by-products in the cement industry are gaining increasing attention in a sustainable development project.In this perspective,many studies focus on finding solutions in order to propose environmentally friendly materials.Nowadays the sediments represent a way to preserve the natural resources by their reuse as a secondary raw material in multiple applications(concrete,roads,landscaped mound,etc.).However,they commonly contain contaminants,organic matter(5%-30%),high water content(50%-200%),and relatively small particle size(Dmax≤300 mm).Therefore to improve the mechanical properties of this material as well as its physiochemical ones,specific methods of characterization and appropriate treatment techniques(calcination,chemical treatment,etc.)are required.This article presents a bibliographical review of the efficient use of sediments in cementitious matrix.It details experimental tests that must be performed to ensure the durability of sediment-based structure and assess their environmental impact under prescribed conditions. 相似文献
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Blood metal levels and metal-influenced immune functions of harbour seals in captivity 总被引：2，自引：0，他引：2
Kakuschke A Valentine-Thon E Griesel S Rosenberger T Mundry R Siebert U Prange A 《Marine pollution bulletin》2008,56(4):764-769
Immunological blood parameters and the effects of environmental pollutants on the immune system are important to assess the health status of seals. Animals living permanently in seal centres are useful for development and validation of diagnostic tools for free-ranging animals. In this study, parameters of cellular immunity as well as metal concentrations in blood and metal influence on cell proliferation of seven seals from a seal centre were investigated repeatedly using multi-element analysis and a lymphocyte proliferation assay. The metal concentrations, except for tin and chromium, were in general comparable to those of free-ranging animals of the North Sea. The unstimulated and mitogen-stimulated lymphocyte proliferation showed strong intra- and inter-individual variability, which reflected variability in activation of the immune status. Furthermore, both immunosuppressive and stimulative influences of metals on lymphocytes were found. Summarising, the methods used in this investigation provided useful information on these animals, and their application to free-ranging animals can be recommended. 相似文献
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Physiological Responses of Five Seagrass Species to Trace Metals 总被引：5，自引：0，他引：5
Trace metal run-off associated with urban and industrial development poses potential threats to seagrasses in adjacent coastal ecosystems. Seagrass from the largest urban (Moreton Bay) and industrial (Port Curtis) coastal regions in Queensland, Australia were assessed for metal concentrations of iron (Fe), aluminium (Al), zinc (Zn), chromium (Cr) and copper (Cu). Trace metal concentrations in seagrass (Zostera capricorni) leaf and root-rhizome tissue had the following overall trend: [Fe] > [Al] > [Zn] > [Cr] > [Cu]. Rainfall events and anthropogenic disturbances appeared to influence metal concentrations in seagrasses with the exception of Al, which does not appear to bioaccumulate. In laboratory experiments, five seagrass species (Halophila ovalis, H. spinulosa, Halodule uninervis, Z. capricorni, Cymodocea serrulata) were incubated with iron (1 mg Fe l−1) and copper (1 mg Cu l−1) and responses assessed by changes in PSII photochemical efficiency (Fv/Fm), free amino acid content and leaf/root-rhizome metal accumulation. Iron addition experiments only affected Halophila spp, while copper additions affected other seagrass species as well. Trace metal contamination of seagrasses could have ramifications for associated trophic assemblages through metal transfer and seagrass loss. The use of photosystem II photochemical efficiency as well as amino acid concentrations and composition proved to be useful sublethal indicators of trace metal toxicity in seagrasses. 相似文献
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Joelle E. Langford Robert A. Schincariol Ranjeet M. Nagare William L. Quinton Aaron A. Mohammed 《Ground water》2020,58(2):258-268
Permafrost covers approximately 24% of the Northern Hemisphere, and much of it is degrading, which causes infrastructure failures and ecosystem transitions. Understanding groundwater and heat flow processes in permafrost environments is challenging due to spatially and temporarily varying hydraulic connections between water above and below the near-surface discontinuous frozen zone. To characterize the transitional period of permafrost degradation, a three-dimensional model of a permafrost plateau that includes the supra-permafrost zone and surrounding wetlands was developed. The model is based on the Scotty Creek basin in the Northwest Territories, Canada. FEFLOW groundwater flow and heat transport modeling software is used in conjunction with the piFreeze plug-in, to account for phase changes between ice and water. The Simultaneous Heat and Water (SHAW) flow model is used to calculate ground temperatures and surface water balance, which are then used as FEFLOW boundary conditions. As simulating actual permafrost evolution would require hundreds of years of climate variations over an evolving landscape, whose geomorphic features are unknown, methodologies for developing permafrost initial conditions for transient simulations were investigated. It was found that a model initialized with a transient spin-up methodology, that includes an unfrozen layer between the permafrost table and ground surface, yields better results than with steady-state permafrost initial conditions. This study also demonstrates the critical role that variations in land surface and permafrost table microtopography, along with talik development, play in permafrost degradation. Modeling permafrost dynamics will allow for the testing of remedial measures to stabilize permafrost in high value infrastructure environments. 相似文献
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Estimation of satellite antenna phase center offsets for Galileo 总被引：2，自引：1，他引：1
P. Steigenberger M. Fritsche R. Dach R. Schmid O. Montenbruck M. Uhlemann L. Prange 《Journal of Geodesy》2016,90(8):773-785