خيارات البحث
النتائج 311 - 320 من 368
The accumulation of arsenic, bromine and iodine in needles of Norway spruce (Picea abies [L.] Karst.) at sites with low pollution
1997
Wyttenbach, A. (Paul Scherrer Inst., Villigen (Switzerland).) | Bajo, S. | Furrer, V. | Langenauer, M. | Tobler, L.
Increased cadmium availability to crops on a sewage-sludge amended soil
1997
Tichy, R. (Institute of Landscape Ecology, Ceske Budejovice (Czech Republic).) | Nydl, V. | Kuzel, S. | Kolar, L.
Sulphur and heavy metal concentrations in Scots pine bark in northern Finland and the Kola Peninsula
1997
Poikolainen, J. (Finnish Forest Research Inst., Muhos (Finland). Muhos Research Station)
Diagnosis of boron, fluorine, lead, nickel and zinc toxicity in citrus plantations in Villarreal, Spain
1997
Aucejo, A. (Valencia Univ., Burjassot (Spain). Dept. de Ingenieria Quimica) | Ferrer, J. | Gabaldon, C. | Marzal, P. | Seco, A.
The difference in brown trout (Salmo trutta L.) blood composition from acidic and limed sites of two rivers in western Norway
1997
Galina, M.S. (Moscow State Univ. (Russian Federation). Faculty of Biology, Dept. of Hydrobiology)
Fish diet and mercury exposure in a riparian amazonian population
1997
Lebel, J. (Quebec Univ., Montreal (Canada). Centre pour l'Etude des Interactions Biologiques entre la Sante et l'Environnement) | Roulet, M. | Mergler, D. | Lucotte, M. | Larribe, F.
Monitoring nitrogen pollution from sugarcane runoff using (15)N analysis
1997
Lindau, C.W. (Louisiana State Univ., Baton Rouge, LA (USA). Nuclear Science Center, Wetland Biogeochemistry Inst.) | Delaune, R.D. | Alford, D.P.
The influence of entrainers on the extraction of polycyclic aromatic hydrocarbons from contaminated soils
1997
Schleussinger, A. | Reiss, I. | Schulz, S.
The extraction of polycyclic aromatic hydrocarbons (PAH) with supercritical carbon dioxide from contaminated soils can be improved by the use of entrainer. In comparison to alcohols or alkanes, water yields good results as moisture of the soil due to its low solubility in the supercritical fluid. Thus, water is only slowly driven out of the soil and can therefore influence the adsorption of the contaminants on the soil particles even at longer extraction times. The agglomeration of soil with elevated water content results in an optimum humidity for the extraction of contaminated soil in the range of 8 - 15%.
اظهر المزيد [+] اقل [-]Polycyclic aromatic hydrocarbons in crude oil-contaminated soil: A two-step method for the isolation and characterization of PAHs
1997
Akhlaq, Mohammed Shahid
A two-step analytical method is developed for the isolation and characterization of polycyclic aromatic hydrocarbons (PAHs) in crude oil contaminated soil. In the first step, those crude oil components were isolated which are easily mobilized with water from the contaminated soil (determination of groundwater pollution potential). In the second step, the fraction containing the remaining crude oil compounds was extracted using toluene. After the cleanup of the fractions, both fractions were analyzed using high-performance liquid chromatography (HPLC).The HPLC of the toluene extracted fraction shows that along with the sixteen priority pollutants from the US-EPA list, many other polycyclic aromatic hydrocarbons (PAHs) are present as well. It is evident from the chromatograms that a significant amount of PAHs are present as is also the case in the fractions eluted by water.The described method allows the determination of total organic pollutants from crude oil, some of them being potential groundwater contaminants. The major part of the total pollutants could not be mobilized by water and therefore remains in the soil, which was extracted in the second step.
اظهر المزيد [+] اقل [-]Do aquatic effects or human health end points govern the development of sediment-quality criteria for nonionic organic chemicals ?
1997
Parkerton, T. F. | Connolly, J. P. | Thomann, R. V. | Uchrin, C. G.
The equilibrium partitioning theory may be used to describe the partitioning of nonionic organic chemicals between water, sediment, and aquatic biota. This paradigm was employed to compare the relative magnitudes of organic carbon-normalized sediment-quality criteria that are intended to protect either benthic organisms from the direct toxic effects of sediment-associated chemicals or humans from the indirect health effects posed by the ingestion of contaminated aquatic animals. Comparison of calculated sediment-quality criteria for a variety of hydrophobic chemicals suggests that human health-based end points often result in more restrictive criteria than aquatic effects-based values. Review of published field data indicates that the equilibrium partitioning paradigm may, depending on contaminant class, either over- or underestimate the extent to which sediment-associated contaminations are bioaccumulated. Despite the limitations of adopting this simple theory for criteria development, calculations reveal that regulatory decisions involving sediments contaminated with such chemicals may be dictated by human health concerns if current risk assessment methodologies are applied.
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