Andhra Pradesh ; Geochemistry ; India ; Lake ; Trace-element ; Water
The distribution of trace elements like Cu, Zn, Ni, Co and Mn in the waters of Pulicat lake has been studied in four aqueous environments: northern, central, southern and channel parts. It is observed that the concentration of the trace elements
increase with increase of pH, chlorides and sodium in both monsoon and dry seasons. The concentration and the behaviour of the trace elements are controlled by adsorption, supplemented by organic reactions and by precipitation in sulphide-rich environments.
Entrainment, displacement and transport of tracer gravels
California ; Carrying capacity ; Experimentation ; Grain size distribution ; Methodology ; Sediment transport ; Stream ; Stream flow ; Tracer ; United States of America
This paper addresses several aspects of the collection, analysis and interpretation of tracer gravel observations, with the general objectives of increasing the information yield of a tracer gravel programme and improving the accuracy of transport
estimates from tracer gravels. The expected variation with grain size of tracer displacement length is developed and illustrated using displacement lengths calculated from measurements of entrainment, surface size distribution and transport rate
MIRIAM. A space-borne sun occultation experiment for atmospheric trace gas spectroscopy
Action anthropique ; Atmosphère ; Aérosol ; Changement global ; Distribution spatiale ; Effet de serre ; Elément-trace ; Environnement ; Télédétection
Aerosol ; Atmosphere ; Environment ; Global change ; Greenhouse effect ; Human impact ; Remote sensing ; Spatial distribution ; Trace-element
The distribution of trace gases in earth's atmosphere will be analysed in a long term German-Russian space mission for more than three years, beginning in 1994. In this paper, the AA. report about the objectives of MIRIAM and present (first
) calculations about the expected retrieval accuracy of atmospheric trace gas column contents.
Etude des biostructures dans des sédiments littoraux pléistocènes. La comparaison avec les traces que laissent les animaux actuels permet une reconstitution des milieux de dépôt sédimentaire. (CM).
In this study, background concentrations were determined by analysing soils considered unaffected by man. Soil profile samples were analysed for major and trace element content of the soils developed on the Minette sandstone on the one hand
and those developed on shales on the other hand. Finally, a limited assessment of the mobility of the trace elements was performed. The results show that in the Minette soil samples, these elements are quite immobile and hence of minimal threat
Etude et discussion des traces de déplacement et d'alimentation observées sur les plans de stratification des dépôts rythmiques de plaine d'épandage fluvioglaciaire dans la sablière Brazeau, Nepean, Ontario.
Background values and geochemical characteristics of 15 trace elements in the source area of the Yangtze River
Chine ; Cours d'eau ; Elément trace ; Géochimie ; Géographie de l'Asie ; Hydrologie ; Yangzi
The natural contents and background values of 15 trace elements Cu, Pb, Zn, Cd, Hg, As, Co, Ni, Cr, Se, Mn, Mo, Fe, V and F in water and sediments in the source area of the Yangtze River have been sampled. These are presented and discussed
Par ses diverses activités, l'homme exerce une influence croissante sur le climat. Dans cet article, l'A. traite du problème de l'influence des éléments traces sur le climat, qui va en augmentant et doit être prise en compte par les décideurs.
L'A. réléchit sur le pourquoi du tracé de frontière. Au caractère fonctionaliste du tracé s'ajoute un système théorique faisant du tracé un préalable à toute observation.
The aim of this study is to gain a simply approach in tracing flowpath and chemical pathway in a forested headwater catchment, the Kawakami Experimental Basin (KEB) situated in Nagano Prefecture, central Japan.
Measurements of concentration of the trace gases active in the greenhouse effect
Atmosphère ; Changement global ; Effet de serre ; Elément-trace ; Ozone ; Pologne ; Prévision ; Technique de recherche
Atmosphere ; Forecast ; Global change ; Greenhouse effect ; Ozone ; Poland ; Research technique ; Trace-element
In this paper the gas chromatograph for the tropospheric measurements of the trace gases active in the greenhouse effect and the ozone layer destruction are described. For the measurements of the CO, CH4 and CO2 an automatic gas chromatograph
The influence of soil interstitial waters on the physicochemistry of major, minor and trace metals in stream waters of the Green Lakes valley, Front Range, Colorado
Action anthropique ; Bassin-versant ; Colorado ; Ecosystème ; Elément-trace ; Erosion des sols ; Etats-Unis ; Hydrochimie ; Hydrologie ; Montagne ; Propriétés du sol ; Qualité de l'eau
Colorado ; Ecosystem ; Human impact ; Hydrochemistry ; Hydrology ; Mountain ; Soil erosion ; Soil properties ; Trace-element ; United States ; Water quality ; Watershed
The objective of this research is to study the physicochemical characteristics of major, minor and trace metals in soil interstitial and stream waters across an alpine watershed, with special emphasis on potentially geochemical reactive areas