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Resultados 281-290 de 347
Sulfate adsorption-desorption in a Swedish forest soil
1998
Gobran, G.R. (Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Ecology and Environmental Research) | Selim, H.M. | Hultberg, H. | Andersson, I.
Above-ground sulfur cycling in adjacent coniferous and deciduous forests and watershed sulfur retention in the Georgia Piedmont, U.S.A.
1998
Cappellato, R. (Emory Univ., Atlanta, GA (USA). Human and Natural Ecology Program) | Peters, N.E. | Meyers, T.P.
Lead (Pb) in Arctic char (Salvelinus alpinus) from oligotrophic alpine lakes: Gills versus digestive tract
1998
Kock, G. (Innsbruck Univ. (Austria). Inst. of Zoology and Limnology) | Triendl, M. | Hofer, R.
The environmental consequences of the conservation tillage adoption decision in agriculture in the United States
1998
Uri, N.D. (Economic Research Service USDA, Washington, DC (USA). Natural Resources and Environment Div.)
Effect of organic materials on partitioning, extractability and plant uptake of metals in an alum shale soil
1998
Narwal, R.P. (Agricultural Univ. of Norway, Aas (Norway). Dept. of Soil and Water Sciences) | Singh, B.R.
Research Articles Metabolism of phenanthrene in cell suspension cultures of wheat and soybean as well as in intact plants of the water mossFontinalis antipyretica : A comparative study Texto completo
1998
Schrenk, Christiane | Steinberg, Christian E. W.
The metabolism of phenanthrene was studied both in cell suspension cultures of wheat (Triticum aestivum) and soybean (Glycine max), and in intact plants of the water mossFontinalis antipyretica. Metabolism in cell suspension cultures strongly differed between the monocotyle and the dicotyle plant. Only small amounts oftrans-phenanthrene-9,10-dihydrodiole and phenanthrene-9,10-dione were detectable in the wheat culture. Soybean cultures, in contrast demonstrated a strong turnover resulting in a 75% reduction of the initial phenanthrene concentration. Metabolites were phenanthrene-9,10-dione, not further characterized polar metabolites and bound residues. Intact plants ofFontinalis antipyretica metabolized only small amounts of phenanthrene. Data obtained from cell cultures did not provide information for the metabolic potential in intact plants. Therefore standardized tests with model systems like suspension cultures lead to inadequate assessment of the ecological risk of certain xenobiotics.
Mostrar más [+] Menos [-]Distribution of platinum group elements (Pt, Pd, Rh) in environmental and clinical matrices: Composition, analytical techniques and scientific outlook : Status report Texto completo
1998
Hees, Torsten | Wenclawiak, Bernd | Lustig, Sönnke | Schramel, Peter | Schwarzer, Michael | Schuster, Michael | Verstraete, Dominique | Dams, Richard | Helmers, Eckard
Trace concentrations of the platinum group elements (PGE; here: Pt, Pd and Rh) play an important role in environmental analysis and assessment. Their importance is based on 1. their increasing use as active compartments in automobile exhaust catalysts, 2. their use as cancer anti-tumor agents in medicine. Due to their allergenic and cytotoxic potential, it is necessary to improve selectivity and sensitivity during analytical investigation of matrices like soil, grass, urine or blood.This paper summarizes the present knowledge of PGE in the fields of analytical chemistry, automobile emission rates, bioavailibility, toxicology and medicine.
Mostrar más [+] Menos [-]Phosphine by bio-corrosion of phosphide-rich iron Texto completo
1998
Glindemann, Dietmar | Eismann, Frank | Bergmann, Armin | Kuschk, Peter | Stottmeister, Ulrich
Phosphine is a toxic agent and part of the phosphorus cycle. A hitherto unknown formation mechanism for phosphine in the environment was investigated. When iron samples containing iron phosphide were incubated in corrosive aquatic media affected by microbial metabolites, phosphine was liberated and measured by gas chromatography. Iron liberates phosphine especially in anoxic aquatic media under the influence of sulfide and an acidic pH. A phosphine-forming mechanism is suggested: Phosphate, an impurity of iron containing minerals, is reduced abioticly to iron phosphide. When iron is exposed to the environment (e.g. as outdoor equipment, scrap, contamination in iron milled food or as iron meteorites) and corrodes, the iron phosphide present in the iron is suspended in the medium and can hydrolyze to phosphine. Phosphine can accumulate to measurable quantities in anoxic microbial media, accelerating corrosion and preserving the phosphine formed from oxidation.
Mostrar más [+] Menos [-]Changes in pH, CEC and exchangeable acidity of some forest soils in southern China during the last 32-35 years
1998
Dai, Z.H. (Chinese Academy of Sciences, Beijing (China). Research Center for Eco-Environmental Sciences) | Liu, Y.X. | Wang, X.J. | Zhao, D.W.
Three species of genus Pinus suitable as bioindicators of polluted environment
1998
Micieta, K. (Comenius Univ., Bratuslava (Slovak Republic). Inst. of Cell Biology) | Murin, G.