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Sedimentological characteristics and mineralization of sediment in the run-of-the river reservoir Djerdap 1 [Yugoslavia]
1998
Perisic, M. | Markovic, I. | Janezic, V. (Geoinstitut, Beograd (Yugoslavia))
In previous works numerous specific changes of water composition in the Danube backwater effects Iron Gate 1 reservoir (Yugoslavia), have been initiated. By studies of conditions of generation and composition of sediments, the models denying importance of assumption on sedimentological features of deposited materials foreseen by the project, have been established, as it was confirmed with more details by newer investigations. The new data on the character of sediments coincide in all elements with changes of water composition, which was formerly presented, thus the knowledges of these phenomena being in that way more important. The data on composition of the deposited material, the macro and micro-composition are of great importance to perceive the influence of new sediments to the quality of surface and groundwater, especially of the sources for water supply, then in a long term for the sudden high risk processes corresponding to a chemical time bomb. Data have confirmed validity of the model of intensified deposition of allochthonous material with plankton and influence of this phenomenon to the processes trough the downstream section.
Show more [+] Less [-]Competitive sorption of heavy metal by soils. Isotherms and fractional factorial experiments
1998
Echevarria, Guillaume | Morera, M.T. | Mazkiaran, C. | Garrido, J.J. | Laboratoire Sols et Environnement (LSE) ; Institut National de la Recherche Agronomique (INRA)-Université de Lorraine (UL) | Universidad Pública de Navarra [Espagne] = Public University of Navarra (UPNA)
Competing ions strongly affect heavy metal sorption onto the solid surfaces of soil. This study evaluated competitive sorption of Cd, Cu, Ni, Pb and Zn on three soils: Calcixerollic Xerochrept, Paralithic Xerorthent and Lithic Haplumbrept. Monometal and competitive sorption isotherms were obtained at 25°C. The individual effect of ions on retention of the others was ascertained by a fractional factorial analysis design. Most of the sorption isotherms belonged to type L subtype 2 in the classification of Giles. In competitive sorption the initial linear part was shorter and the knee sharper when compared with monometal sorption isotherms. Parameters related to sorptive capacity, such as Point B, Langmuir monolayer and Freundlich distribution coefficient, were higher in monometal than in competitive sorption, and in basic soils than in acidic soil. Calcium desorbed at different points of the sorption isotherms indicated that cationic exchange with Ca was the main retention mechanism in calcareous soils. For Pb, the ratio Ca desorbed/Pb sorbed was close to one; for Cu, Ni and Zn the ratio ranged from 1.20 to 1.37, probably due to partial dissolution of calcium carbonates by hydrolytic processes during retention. On the other hand, Cd had a ratio around 0.6 reflecting another additional retention mechanism, probably surface complexation. Fractional factorial design confirmed that the presence of the cations investigated reduced the amount of the five metals retained, but the presence of Cu and Pb in the system depressed Ni, Cd and Zn sorption more than the inverse. Cation mobility was enhanced when equilibrium concentration increased and the effect was higher in Ca-saturated soils.
Show more [+] Less [-]Biological transformation of phenols in a sandstone aquifer
1998
Broholm, M.M. | Arvin, E. (Danmarks Tekniske Univ., Lyngby (Denmark))
[In-situ remediation by oxygen injection of limestone polluted with petrol]
1998
Larsen, L.C.
Heavy metal concentrations in consecutive saturation extracts of dredged sediment derived surface soils
1998
Tack, F.M.G. | Singh, S.P. | Verloo, M.G. (Laboratory for Analytical Chemistry and Applied Ecochemistry, University of Ghent, Coupure Links 653, B-9000 Gent (Belgium))
Optimizing air quality management in Europe and North America: justification for integrated management of both oxidized and reduced forms of nitrogen
1998
Cowling, E.B. | Erisman, J.W. | Smeulders, S.M. | Holman, S.C. | Nicholson, B.M. (College of Forest Resources, North Carolina State University, Box 8002, Raleigh, NC 27695 (USA))
Effects of nesting yellow-legged gulls (Larus cachinnans pallas) on the heavy metal content of soils in the Cies Islands (Galicia, North-West Spain)
1998
Perez, X.L.O. (Departamento de Edafoloxia e Quimica Agricola, Facliltade de Bioloxia, 15 706 Santiago de Compostela (Spain))