خيارات البحث
النتائج 1 - 6 من 6
The REC-framework: Risk reduction, Environmental merit and Costs
1997
Okx, J.P. | Nijboer, M.H. | Visser-Westerweele, E.P.C. | Nijhof, A.G.
Decomposer communities in contaminated soil: is altered community regulation a proper tool in ecological risk assessment of toxicants?
1997
Salminen, J.E. | Sulkava, P.O. (University of Jyvaskyla, Department of Biological and Environmental Science, P.O. Box 35, FIN-40351 Jyvaskyla (Finland))
The environmental hazard caused by smelter slags from the Sta. Maria de la Paz mining district in Mexico
1997
Manz, M. | Castro, L.J. (UFZ Centre for Environmental Research Leipzig-Halle, Department of Chemical Ecotoxicology, PO Box 2, D-04301 Leipzig (Germany))
General assessment of the occurrence of keratinolytic fungi in river and marine beach sediments of catalonian waters (spain)
1997
ULFIG, K. | Guarro, J. | CANO, J. | Gené Badía, Joan | Vidal, P. | Figueras, M. J.
Sediments from 8 river mouths of the Catalonian coast (Spain) were examined for keratinolytic fungi. Out of 1250 river and marine samples examined, 499 (39.9%) were positive for these fungi. Aphanoascus fulvescens (anamorph + teleomorph), Chrysosporium keratinophilum, Ch. tropicum, Ch. an. of Arthroderma curreyi, Ch. pannicola, Ch. europae and Ch. indicum were the predominant species in the sediments. River samples were rich in keratinolytic fungi, whereas in marine beach sediments they occurred sporadically. The results of a preliminary experiment demonstrated that, marine water exerted a dramatical impact on river keratinolytic fungi causing their total or near-total elimination. The qualitative and quantitative compositions of river keratinolytic mycoflora depended on the degree of water contamination with sewage and on natural factors (mainly temperature). The keratinolytic mycoflora of two rivers was possibly altered dramatically by water contaminants, including poisons of industrial origin, and marine salinity. The problem of public health risk resulting from the distribution of keratinolytic fungi within the highly-frequented recreational waters is discussed.
اظهر المزيد [+] اقل [-]Accumulation of cadmium and zinc from diffuse immission on acid sandy soils, as a function of soil composition
1997
Wilkens, B. J. | Loch, J. P. G.
Sandy soils, in the border area of Belgium and the Netherlands (the Kempen region), are heavily contaminated by atmospheric deposition of cadmium and zinc from nearby smelters. Groundwater contamination by leaching from these low retention soils is subject of study. There are reports of high cadmium and zinc concentrations in groundwater in the area, but in most cases the direct sources are unknown. In an attempt to predict present or future risk of groundwater contamination by soil leaching, metal binding processes (retardation) were studied that are specific for these soil types under the existing acidifying conditions. From four fields nine contaminated profiles were sampled and analyzed for cadmium and zinc. Average concentrations of 131μg g⁻¹ zinc and 1.6μg g⁻¹ cadmium with maximum values of 2989μg g⁻¹ respectively 16.3μg g⁻¹ were found. In addition pH and contents of organic matter, aluminium, iron, and manganese were determined. The relative importance of these soil parameters for metal retardation is derived from the profiles. The data show that organic matter is the most important soil component for binding cadmium and zinc. Adsorption of cadmium and zinc on aluminium, iron and manganese (hydr) oxides appears to be of minor importance at low pH (<5.5).
اظهر المزيد [+] اقل [-]Increased cadmium availability to crops on a sewage-sludge amended soil
1997
Tichý, R. | Ný, V. | Kužel, S. | Kolář, L.
Analysis of spatial distribution of sewage-sludge born cadmium on the experimental plot revealed positive correlation of total cadmium and organic matter. Soil pH fluctuated randomly on the field. ‘Bioavailable’ concentrations, as determined by NH₄-acetate extraction, were closely correlated to the total cadmium levels, and only negligible effects of pH and/or organic matter fluctuations were recorded. Desorption model using modified Freundlich isotherm was applied to predict risks of cadmium solubilization at different conditions. Simulations revealed that the organic matter content within the ranges found at the experimental field cannot support a proper immobilization of cadmium at pH-range observed at the field. The phenomenon was explained by ineffective care for the soil in the past.
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