An Approach for Classification of Groundwaters by Synchronous Fluorescence Spectroscopy and Discriminant Analysis

Monitoring and evaluation of groundwater quality in drinking water protectorates is of particular interest if the uncontrolled entry of pollutants, for example by infiltrating river water, cannot be excluded. A fluorescence spectroscopic method is presented as possible alternative to the conventional expensive hydrochemical investigations. This method uses the information yielded by synchronous fluorescence spectra. After a Fourier transformation of the original spectra and a following discriminant analysis, the samples can be classified in different groups corresponding to the different types of groundwater. The method was tested in the drinking water protectorate of a waterworks of a German metropolis (Halle, Sachsen-Anhalt). We found a prediction rate of about 90% in the investigated case.     

Schwefel-, Kohlenstoff- und Sauerstoff-Isotopenuntersuchungen am Kupferschiefer als Beitrag zur genetischen Deutung

The isotopic composition of sulfur, carbon and oxygen was determined in 106 samples mainly from profiles of Kupferschiefer occurences in N.W. Germany and N. Holland. From the bulk samples pyrite, non-pyritic sulfides and gypsum have been concentrated for isotopical analysis. C¹³/C¹²-ratios were measured in carbonates and in organic carbon and O¹⁸/O¹⁶-ratios in carbonates and in sulfates. Analytical data on CO₂, C, S in all samples and on Fe, Cu, Zn and Pb in a part of the profile samples are presented.Primary sulfates can be distinguished from sulfates formed from oxydized sulfides by their sulfur and oxygen isotopic composition. The abundance of light carbon and sulfur as well as the correlation between the S- and C-values are strong indications for bacterial sulfate reduction. Highly S³²-enriched metal sulfides (S³⁴ averages –30 to –35) have fixed the H₂S from bacterial production at its starting conditions. A large variation of the sulfide-S-values (–4 to –44) and the occurence of S³⁴-enriched residue-sulfates from closed systems (+11 to +26) support the above mentioned theory. A systematic fractionation of sulfur between the sulfur minerals as observed in hydrothermal deposits (increasing S³⁴ in the sequence: pyrite>sphalerite>chalcopyrite>galena) has not been detected. In our case the regular difference in S³⁴ between the sulfides is consistent with the idea of a successive precipitation of the metals due to their different solubility with increasing bacterial H₂S production. In such a sequence the increase of S³⁴ is due to the consumption of light sulfate by bacterial reduction after the transition from an open to a closed system.It is alternately discussed, whether bacterial reduction and metal precipitation took place in bodies of stagnant sea water above or within the sediment. Presuming a precipitation of metals in a closed water-reservoir observations of other authors concerning the vertical sequence of metals and of the present author regarding the accumulation of S³⁴ in the sequence of precipitated sulfides can be easily explained.Evidence from isotope fractionation in sediment sequences favours the assumption of a precipitation of metals in the sediment: light carbon above the zone rich in carbonates (with a marine carbon composition) and metals. This characteristic change in the C¹³/C¹²-ratio is due to the increasing influence of light carbon dioxide of biogenic origin. Assuming the production of H₂S as restricted to the sediment, the transition from the open to the closed system as a result of growing thickness of the sediment (with lowered permeability for sulfate- and metalbearing water) controls the sequence of carbon composition. The restriction of metal precipitation in the sediment causes difficulties in interpreting regular zoning of metals and the metal supply. Especially the numerous exchanges of pore water required for the supply of sulfate and metals in the bituminous sediment with very low permeability cannot be explained.The assumption of a syngenetic sulfide precipitation is confirmed by the results of the carbon isotope analysis. The trend to heavy carbonates in the sequence of the profiles can be interpreted as due to rising marine influence with time in the early Zechstein basin. This trend is only interrupted several times in the Kupferschiefer-sediment by the occurence of light carbonates of biogenic origin above zones of sulfide accumulation. A model of epigenetic metal supply forming this regular pattern of correlated sulfur and carbon distribution and composition cannot be constructed. The evidence from our data favours the assumption of concurring processes of carbon fixation in carbonates and in organic substances and sulfur precipitation as sulfides during the formation of the sediment.

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Herrn Prof. Dr. K. H. Wedepohl danke ich für die Stellung des Themas, Überlassung des Probenmaterials und für sein reges Interesse am Fortgang der Arbeit. Meinen Dank möchte ich auch allen Mitarbeitern der mineralogischen Anstalten und des Zentrallabors aussprechen, die mich durch vielerlei Anregungen und Diskussionsbereitschaft unterstützt haben. Die massenspektrometrischen Untersuchungen wurden von der Deutschen Forschungsgemeinschaft durch die Einrichtung des Zentrallabors für Geochemie der Isotope an der Universität Göttingen ermöglicht.     

The monosaccharide spectra of natural waters

Monosaccharides were determined in waters and sediment pore waters from a wide variety of environments and locations. Desalting was performed by electrodialysis and concentrated extracts were analyzed by two forms of liquid chromatography. At least 12 sugars were identified. Glucose and fructose were the dominant monosaccharides in nearly all samples examined. Analyses of over 150 seawater and sediment pore water samples showed that fructose is highly significantly correlated (>0.99) with glucose concentrations. Laboratory kinetic experiments on the epimerization reaction, glucose ? fructose, in sterilized natural seawater in the dark, yielded a forward rate constant, k₁, of 1.2 × 10^?5 h^?1 at 25°C and 1.6 × 10^?7 h^?1 at 2°C. The approximate time required to attain equilibrium at 25°C was 1.1 y and at 2°C, 15.4 y; the measured equilibrium constant was in the range 0.3–0.4. The actual ratio of fructose to glucose in natural water samples was usually in the range 1.0–1.4/l, independent of the total monosaccharide concentrations, which varied in the samples by a factor of ～100. Several possible explanations for the apparent discrepancy in the determined and found ratios are discussed: the presence of universal, as yet, undiscovered major biological sources for fructose in marine environments; preferential utilization of glucose; preferential incorporation of fructose into or onto inorganic colloids; and preferential formation of fructose-transition metal ion associations.     

Thermal modeling of Carboniferous to Triassic sediments of the Karawanken Range (Southern Alps) as a tool for paleogeographic reconstructions in the Alpine–Dinaridic–Pannonian realm

Vitrinite reflectance was measured in Late Carboniferous to Triassic shales, siltstones and marls of the Karawanken Range. Thermal models of the central South-Karawanken Range were calibrated on the basis of these data. They suggest an eroded overburden of more than 3,200 m of Jurassic to Cretaceous sediments and a heat flow in the range of 42 to 60 mW m^?2 during the time of maximum subsidence. Because the reconstructed thermal history of the South-Karawanken Range is very similar to the thermal history of the Generoso basin (western Southern Alps), these data provide strong evidence for a deep basinal position of the Southern Karawanken Range during Jurassic to Cretaceous times. A vitrinite reflectance anomaly at the northern margin of the South-Karawanken Range is explained by advective heat transport during the Oligocene. The heat source for the anomalies at the western margin of the Seeberg Rise and in the area between the Periadriatic Lineament and the Donat Fault Zone is unknown. Vitrinite reflectance in Late Triassic sediments indicates the South-Karawanken Range and the South-Zala Unit of the Pannonian basement as exotic blocks in the Sava Composite Unit. This is explained by Miocene displacement of structural units, which were derived from different paleogeographical segments of the Permo-Mesozoic western Tethyan margin.     

The future of industrial cities and regions in central and eastern Europe

Economic transition in central and eastern Europe (CEE) has had a particularly strong impact on industrial cities and regions. Following their economic collapse, most of them are now confronted with serious problems such as high unemployment and vast ecological damage. The paper presents findings from a pan European research project that investigated the problems of these cities and regions as well as the strategies being adopted to cope with structural change. It examines the differences in approaches and addresses the question whether existing EU policy is suitable for supporting the redevelopment of old industrial cities and regions in CEE countries. The paper concludes with recommendations for future directions in policy making.     

A Discussion of IGS Solutions and Their Impact on Geodetic and Geophysical Applications

The International Association of Geodesy officially established the International GPS Service (IGS) on Janaury 1, 1994. Its prime objective is to provide support and a rerefence system for a wide variety of scientific and practical applications involving GPS. To fulfill its role the IGS also generates, in addition to its fundamental products (orbital/staion positions and consistent Earth orientation parameters), additional reference-system products providing the necessary infrastructure, standards, and means of calibrations for timing and various atmospheric applications of GPS. The generation and efficient application of IGS products and their impact on a number of positioning and atmospheric applications, including low earth orbit satellites, is reviewed and discussed. @ 1998 John Wiley & Sons, Inc.     

The Bayesian approach to an internally consistent thermodynamic database: theory, database, and generation of phase diagrams

An internally consistent thermodynamic dataset has been derived for 148 endmember phases (145 solids and 3 fluids) comprising the elements Li, Na, K, Be, Mg, Ca, Ti, Cr, Mn, Fe, Zn, Al, Si, C, H, and O. This has been achieved by simultaneous treatment of phase property (like standard enthalpy of formation, standard entropy, molar heat capacity, molar volume, thermal expansivity, bulk modulus etc.) and reaction reversal data by the Bayesian method. The theory underlying the approach, and the computational methods involved, are briefly outlined. (For the benefit of readers unfamiliar with inference statistics, the basic concepts of the Bayes method are also presented in such a way that they can be grasped intuitively.) Although not yet addressed, this method can be extended to refine the thermodynamic mixing properties of crystalline solutions. The sources of the input data, culled from the literature, are summarized in the Appendix. The resulting database is succinctly documented in this paper. It includes the enthalpies of formation and entropies, their uncertainties, and the correlation among them. The database allows calculation of P-T, T-X _CO2, P-X _CO2, and T-f _O2 sections, with error propagation into the computed phase diagrams on a routine basis. A user-friendly computer program has been written to generate such phase diagrams. It is public domain software. The software and the thermodynamic database (which includes a complete documentation of the thermodynamic data above and beyond those listed (Table 2, here) may be downloaded from the web site http://homepage.ruhr-uni-bochum.de/niranjan.chatterjee/Index.htm. Examples of computed phase diagrams are given to illustrate the quality of the data and the capabilities of the software. Received: 11 March 1998 / Accepted: 11 June 1998     

Mercury colonial footprint in Darién Gulf sediments,Colombia

The mercury (Hg) deposition history in the Darién Gulf is reconstructed from three sediment cores spanning up to 1,000 years. Knowledge on the contribution to global Hg budget from the Caribbean is limited. Patterns of water circulation, sediment deposition rates, cataclysmic atmospheric inputs, and post-depositional migration have been considered in Hg trapping in the seabed. The sediment delivery rates to the coastal zone over the Late Holocene have increased from 0.2 to 1 cm year^?1 owing to anthropogenic influence. This alteration took the form of geological effects, like coastal morphology change, that played a major role in Hg downcore signal preservation. Natural background Hg levels in Southern Caribbean sediments (77.0 μg kg^?1) are up to three times higher than preindustrial signals at other latitudes, because of volcanic contributions from the Pacific ring of fire. Enrichment factors rose from 0.9 to 1.5 (70.1–113.5 μg kg^?1) within profiles related to Hg usage since Spanish colonial times between the calendar years 1550 and 1811.