Search results for "Lessivage"
showing 8 items of 8 documents
Leaching of diuron and oryzalin in undisturbed lysimeters of three vineyard soils (Vosne-Romanée, 21)
2001
La mobilité du diuron et de l'oryzalin a été étudiée en colonnes de sol non perturbé au laboratoire. Les sols étudiés sont trois sols viticoles de la région Bourgogne (Vosne-Romanée, 21) et ont été prélevés selon une topolithoséquence. Leurs teneurs en carbone organique sont respectivement de 1,2 %, 1,7 % et 2,2 % pour le sol brun calcaire de mi-pente (SBC MP), le sol brun calcaire de bas de pente (SBC BP) et la rendzine. Après une hauteur de pluie simulée de 845 mm, les percolats respectifs de la rendzine, du SBC MP et du SBC BP contiennent des quantités plus importantes de diuron (3,2 %, 11,8 % et 18,8 %), que d'oryzalin (0,2 %, 4,9 % et 3,7 % des quantités appliquées). Dans les colonnes …
Geochemical characterization of surface waters and groundwater resources in the Managua area (Nicaragua, Central America)
2008
This paper reports new geochemical data on dissolved major and minor constituents in surface waters and ground waters collected in the Managua region (Nicaragua), and provides a preliminary characterization of the hydrogeochemical processes governing the natural water evolution in this area. The peculiar geological features of the study site, an active tectonic region (Nicaragua Depression) characterized by active volcanism and thermalism, combined with significant anthropogenic pressure, contribute to a complex evolution of water chemistry, which results from the simultaneous action of several geochemical processes such as evaporation, rock leaching, mixing with saline brines of natural or…
Laboratory leaching studies of oryzalin and diuron through three undisturbed vineyard soil columns
2004
Article de revue (Article scientifique dans une revue à comité de lecture); International audience; The leaching of diuron and oryzalin through undisturbed soil columns was studied in the laboratory using three vineyard soils from Vosne-Romanée (Burgundy): a rendosol, a calcosol and a vegetated calcosol. After 845 mm of simulated rainfall in 15 days, soil leachates contained higher amounts of diuron (3.2%, 11.8% and 18.8% of applied diuron, respectively) than oryzalin (0.2%, 4.9%, 3.7%, respectively). A greater proportion of soil extractable residues was obtained for diuron (42.5%, 26.8% and 32.2%, respectively) than for oryzalin (14.7%, 12% and 15.5%, respectively). The greater mobility of…
EDXRF and TXRF analysis of elemental size distributions and environmental mobility of airborne particles in the city of Riga, Latvia
2004
Airborne particles were investigated in the central part of Riga during October 2000. Mass, black carbon and elemental concentrations of airborne particles were measured on Teflon filters from a dichotomous impactor, which samples fine (<2.5 µm) and coarse (2.5‐10 µm) fractions of particles. In order to obtain more detailed information on the size distributions of different elements, a seven-stage Batelle cascade impactor was used, in which quartz plates treated with silicone grease were utilized as backing for the different stages. Total reflection x-ray fluorescence (TXRF) and energy-dispersive x-ray fluorescence (EDXRF) spectrometry were used for elemental analysis on the quartz plates a…
Changes of lead silicate glasses induced by leaching
1998
Abstract The structural differences in the surface region between freshly fractured and leached silicate glasses containing 16.7, 18.8 and 44.4 mol% PbO, respectively, were investigated by photoelectron spectroscopy (XPS). The optical properties and the thicknesses of leached layers were determined by reflection measurements. The binding energies of the O1s signal components for untreated samples can be ascribed to non-bridging (NBO) and bridging (BO) oxygen and oxygen associated with lead as network former (OPb). The binding energy of OPb was found to be 529.1 ± 0.2 eV. For quantitative conclusions, relative XPS sensitivity factors were determined for oxygen, silicon and lead in these glas…
Methods of metal release assessment in soil water at anoxic sites
2006
Department of Geology, Vienna University, Vienna, Austria Metal mobility at contaminated sites can be assessed by soil water investigations or by leaching tests. Leaching tests are usually carried out in open contact with the atmosphere disregarding possible changes of redox conditions. This can affect the original metal speciation and distribution, particularly when anoxic samples are investigated. In this study, the applicability of common leaching tests (the German S4 test (S4), ammonium nitrate extraction (AmmN), and saturation soil extraction (SSE)) is tested for the assessment of zinc release from sulfide-bearing flotation residues of a former ore mine. Results are compared to soil so…
Leaching of n and c from birch leaf litter and raw humus with special emphasis on the influence of soil fauna
1988
Abstract To examine the role of a community of soil animals in N-mineralization and C fluxes in dead organic matter, we established a microcosm system with substrates composed of: (a) birch leaf litter; (b) raw coniferous humus; and (c) litter on humus. Every 3–4 wks the substrates were irrigated with distilled water, and the amounts of NO5-N, NH4-N, total-N and total-C (as well as humic substances at one recording) in the leachates were analyzed. At the end of the experiment, water-soluble and exchangeable forms of N were measured in the test materials. The differences in the release of N were clear both between the replicates with and without soil animals and between the different forms o…
Effect of micro-aeration and leachate replacement on COD solubilization and VFA production during mono-digestion of grass-silage in one-stage leach-b…
2010
The effect of micro-aeration and leachate replacement with fresh water on chemical oxygen demand (COD) solubilization and volatile fatty acid (VFA) production during the mono-digestion of grass-silage in one-stage leach-bed reactors (LBRs) was investigated in four LBRs, L0 (control), L1, L2 and L3 in batch mode at 35 + or - 1 degrees Celsius for 57 days. Results showed that leachate replacement without pH adjustment (L3) resulted in 2.7 and 1.3 times more SCOD in the leachate compared to control (L0) or leachate replacement with initial pH adjustment (L1), respectively. Micro-aeration at flow rate of 1 L min(-1) (2.5 L of air) in L2 resulted in 4-fold increase in VFA production (from 2.2 to…