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  • 1
    Electronic Resource
    Electronic Resource
    Fossil Fuel Biomarkers in Sewage Sludges: Environmental Significance (1999)
    Springer
    Naturwissenschaften 86 (1999), S. 484-488 
    Details
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Notes: Abstract  Fossil fuel biomarkers, or "molecular fossils," are specific organic substances found in coals, petroleums, and sedimentary rocks. They are formed during millions of years of sedimentary burial by geochemical alteration of biological molecules, such as cholesterol, under the effect of biodegradation, temperature, pressure, and mineral catalysis, to produce geochemically mature molecules, for example, aromatic steroids (Fig. 1). Since fossil fuel biomarkers have a very specific molecular structure betraying fossil fuel sources, such markers should be useful in assessing the fossil fuel contamination of various modern media such as soils, plants, waters, and modern sediments. Here the identification of fossil fuel biomarkers of high geothermal maturity in sewage sludges provides evidence of the contamination of sludges by petroleum products. The most likely sources of contamination are contaminated vegetal food, road dust, and soil particles carried by rain water.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001140050659
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  • 2
    Electronic Resource
    Electronic Resource
    Measurement of Pb2+, Cu2+ and Cd2+ binding with mucilage exudates from maize (Zea mays L.) roots (1986)
    Springer
    Biology and fertility of soils 2 (1986), S. 29-34 
    Details
    ISSN: 1432-0789
    Keywords: Root mucilages ; Maize ; Lead ; Copper ; Cadmium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The pectic nature of root mucilages suggests a hypothetical action of these substances on heavy metal flux into the root. In this study the existence of relations between heavy metals and root mucilages were verified and quantified. In order to obtain substantial amounts of pure root mucilages, two methods of collection were developed, using: (1) maize plants grown in the field and (2) hydroponic axenic cultures. The study of mucilage-metal binding was conducted using the dialysis method, which was developed in a previous work. Results show that root mucilages are able to bind metals. The importance of the binding depends on the nature of the cation, following the order Pb 〉 Cu 〉 Cd. These reactions could be due to exchange processes involving mucilage cations (Ca2+, Mg2+) and heavy metals. The role of mucilages on the retention of heavy metals in the rhizosphere is also discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00638958
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  • 3
    Electronic Resource
    Electronic Resource
    Comparison of the adsorption of maize root mucilage and polygalacturonic acid on montmorillonite homoionic to divalent lead and cadmium (1987)
    Springer
    Biology and fertility of soils 5 (1987), S. 13-17 
    Details
    ISSN: 1432-0789
    Keywords: Maize root mucilage ; Polygalacturonic acid ; Montmorillonite ; Lead ; Cadmium ; Adsorption isotherms ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Root mucilage material (RM) was isolated from maize plants grown in the field, and its affinity to montmorillonite (M) homoionic to Pb2+ and Cd2+ was compared with that of a commercial polygalacturonic acid (PGA). Adsorption isotherms of the commercial and natural materials on the two clay systems were compared in unbuffered systems at pH 3 and pH 6. Adsorption of PGA occurred only at pH 3, and was higher on M-Pb than on M-Cd. In contrast, the adsorption of RM was higher on M-Cd than on M-Pb. Total amounts of RM adsorbed at pH 3 were about 3 times lower on M-Cd and 20 times lower on M-Pb than the respective amounts of PGA adsorbed at the same pH. Polygalacturonic acid had a high content of relatively well dissociated (pKa = 3.5) carboxylic groups, and adsorbed on the clay surface at pH values lower than its pKa. At pH 6, the dissociation of the acid groups favoured its solubility, and the metal cations were then probably displaced by ion exchange. The lower affinity of RM to the clay materials was related to its average molecular weight, which was lower than that of PGA, and to its water solubility, which was higher than that of PGA. The low pH dependence of the adsorption of RM was related to its lower carboxylic acidity and higher content in hydroxyl and amino groups.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00264339
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  • 4
    Electronic Resource
    Electronic Resource
    Chemical characterization and agronomic effectiveness of phosphorus applied as a polyphosphate-chitosan complex (1994)
    Springer
    Nutrient cycling in agroecosystems 37 (1994), S. 151-158 
    Details
    ISSN: 1573-0867
    Keywords: 13C CP/MAS NMR ; chitosan ; hexametaphosphate ; 31P MAS NMR ; pyrophosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract This work was undertaken to characterize a chitosan-polyphosphate complex (CH-PP) and to evaluate its agronomic effectiveness as a source of phosphorus for ryegrass (Lolium perenne) grown on loamy and clayey soils. High resolution solid state31P and13C nuclear magnetic resonance were used to characterize this complex and to monitor the structural changes occurring to it during an 8-week incubation period in a loamy soil. A pot experiment was conducted on the two soils after labelling the available P with32PO4 ions. This experiment allowed for the determination of the agronomic effectiveness of the chitosan-polyphosphate complex compared to polyphosphate and to monocalcium phosphate. Results showed that chitosan immobilized up to 147 mg P kg−1 as pyrophosphate and hexametaphosphate. This reaction did not involve major structural changes in the pyrophosphate or hexametaphosphate groups nor in the chitosan. The chitosan-polyphosphate complex was as efficient as the polyphosphate alone to sustain the P nutrition of ryegrass. The relative agronomic effectiveness of these P sources was slightly lower compared to that of monocalcium phosphate. The high P fertilizing value of the chitosan-polyphosphate complex was attributed to its gradual hydrolysis in the soil. The potential interest of chitosan to remove polyphosphates from waste waters while preserving the high P fertilizing value of polyphosphates was addressed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00748555
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Phosphate fixing capacity of soils: A survey, using the isotopic exchange technique, or soils from north-eastern France (1989)
    Springer
    Nutrient cycling in agroecosystems 19 (1989), S. 103-111 
    Details
    ISSN: 1573-0867
    Keywords: Phosphate ions ; soil fixing capacity ; 32P ; isotopic exchange kinetics ; northeastern France
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A large variety of soil samples was collected from farms located in two north-eastern regions of France. Their phosphate fertility was assessed by the isotopic exchange kinetics method which allows for the measurement of a r1/R ratio, where r1 is the quantity of radioactivity still present in solution one minute after the injection of a quantity of radioactivity R into a soil-solution system at steady-state. The r1/R parameter gives an estimate of the soil fixing capacity for phosphate ions (PFC). Results of the analysis of 233 soil samples revealed that the great majority of soils from these areas exhibit a high PFC. Neither the soil type nor mode of utilization appeared sufficient for prediction of the PFC. Attempts to express the PFC as a function of other soil parameters (pH, clay, organic matter, calcium carbonate and exchangeable cations), resulted in a significant regression equation involving soil clay content and soluble phosphate. Due to high PFC of soils in the Lorraine area, phosphate fertilizer could be applied at a time as close as possible to the plant requirements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01054682
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