Download or read book The Voltammetric Determination of Trace Metal Concentrations and Organic Complexation in Seawater written by and published by . This book was released on 1992 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biological processes can strongly influence the oceanic chemistries of trace metals and, in turn, trace metals can influence plankton production and community structure. Our knowledge of the oceanic concentrations, distributions, and cycles of trace metals have advanced significantly (see Bruland 1983; Whitfield and Turner 1987). We now know the bioactive trace metals exist at nanomolar (10-9 M) to picomolar (10-12 M) concentrations in oceanic waters. In addition, marine chemists have recently advanced their ability to characteristics the chemical speciation of these bioactive trace metals in the sea; that is, we can now determine their free ion concentrations and the extent to which certain trace metals interact with organic and inorganic ligands naturally present in oceanic surface waters.
Download or read book Complexation of trace metals in natural waters written by C.J. Kramer and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 453 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is presently well recognized that total concentrations of trace elements in any environmental compartment supply insufficient information to understand important phenomena. The distinction and separate analysis of specific chemical species are essential for understanding cycles in the aquatic environment, involving identification and quantification of sources, transport pathways, distributions and sinks, or, in the area of interactions between trace elements and organisms to understand uptake, distribution, excretion mechanisms and effects. In the past, various ways have been developed to determine the nature and extent of complexation of trace elements in natural systems. Approaches have been followed along very different lines. These have not always been fully appreciated by specialists working in even related fields of complexation research. The first International Symposium on the Complexation of Trace metals in Natural Waters was held at the Netherlands Institute for Sea Research (NIOZ, Texel, the Netherlands from 2-6 May 1983. The scientific programme was planned by the chief organizers Drs. C.J.M. Kramer and J.C. Duinker (NIOZ) together with Prof. Dr. H.W. Nurnberg (Kernforschungsanlage, Julich, Federal Republic of Germany) and Dr. M. Branica (Rudjer Boskovic Institute, Zagreb, Yugoslavia).
Download or read book Trace Element Speciation in Surface Waters and Its Ecological Implications written by Gary G. Leppard and published by Springer. This book was released on 1983-03 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Trace Metals in Sea Water written by C. Wong and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 913 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years, rapid scientific advances have been shattering classical concepts of oceanic trace metals concentrations. Most of the data gathered before the mid-1970s have had to be discarded. Possible associations of organic and inorganic ligands with the metals were throwing views of metal speciation into great uncertainty. Biological effects of metals need to be re-examined after recent revelations of unsuspected metal contaminations in methodology. The investigations appear chaotic, yet exciting. It implies that a new order is going to replace the past. Now, an opportunity opens its door to a brave new world for the young generation of scientists to put metal chemistries in the oceans into perspectiveo This N. AoToO. International Conference on "Trace Metals in Sea Water" hoped to catalyze this exciting process of unifying various aspects of trace metals in sea water in future years o The Conference, in the form of an Advanced Research Institute supported by the Scientific Affairs Division of NoAoT. O. supple mented by further assistance of the UoS. Office of Naval "Research, was held at the "Ettore Majorana" Center for Scientific Culture in the medieval town of Erice on the island of Sicily, Italy from March 30 to April 3, 1981. It was the first organized gathering of international scientists in this specialized field. Seventy scientists with various expertise in different aspects of the subject were present: including those from NoAoT. Oo countries (Canada, France, F. R. Germany, Greece, Iceland, Italy, U. K.
Download or read book Studies of the Voltammetric Determination of Trace Metals in Seawater written by Kenneth W. Bruland and published by . This book was released on 1982 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: The basic voltammetric cell consists of the analyte whole metal concentration is to be determined and three electrodes. During the cathodic deposition mode, metal ions are reduced by the potential at the working electrode and deposited on the mercury film at the electrode surface as a metal-Hg-amalgam. The potential at the working electrode is induced by the polarograph through the counter electrode with the reference electrode taken as zero. The actual potential of the working electrode depends upon the type of reference of electrode used. (Author).
Download or read book Organic Ligands in Marine Trace Metal Biogeochemistry written by Kristen N. Buck and published by Frontiers Media SA. This book was released on 2018-01-11 with total page 305 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research topic highlights the most recent accomplishments of a Scientific Committee on Oceanic Research (SCOR) Working Group, SCOR WG 139: Organic Ligands - A Key Control on Trace Metal Biogeochemistry in the Ocean.
Download or read book Practical Guidelines for the Analysis of Seawater written by Oliver Wurl and published by CRC Press. This book was released on 2009-06-09 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt: As we discover more about the role of the ocean in global changes and identify the effects of global change on the ocean, understanding its chemical composition and processes becomes increasingly paramount. However, understanding these processes requires a wide range of measurements in the vast ocean, from the sea surface to deep-ocean trenches, fr
Download or read book A Study of Certain Trace Metals in Sea Water Using Anodic Stripping Voltammetry written by William Francis Fitzgerald and published by . This book was released on 1969 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: Anodic stripping voltammetry utilizing a thin film mercury composite graphite electrode has been evaluated and applied for the direct analysis of the metals, Zn, J Cu, Pb, and Cd in sea water. The electrode was observed to follow theoretical behavior for thin film electrodes and the technique was found not to be adversely affected by dissolved organic material in sea water. Good precision (ca., 5%) was obtained in both coastal and open ocean waters at the in situ concentrations of Zn, Cu, Pb, and Cd. It was shown that this method is at present most suitable for measurements of Cu, Pb, and Cd in sea water. Evidence is given suggesting that Ni may interfere with the determination of Zn through formation of an intermetallic compound, and further studies are indicated to understand this phenomenon. The anodic stripping apparatus was adapted and used conveniently on shipboard. It was demonstrated that stripping analysis could be combined with a method for the destruction of dissolved organic matter- (photo-oxidation with ultra-violet radiation), and with an acidification procedure to obtain measurements of trace metal speciation in sea water.
Download or read book Cadmium in the Environment written by Mislin and published by Birkhäuser. This book was released on 2013-03-08 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Iron Transport in Bacteria written by Jorge H. Crosa and published by Amer Society for Microbiology. This book was released on 2004 with total page 499 pages. Available in PDF, EPUB and Kindle. Book excerpt: provides an up–to–date survey of iron transport systems in bacteria; details iron transport and its regulation in E.colias a prototype for iron transport systems in gram–negative bacteria; includes chapters on the major gram–negative, gram–positive and acid–fast bacterial pathogens – their iron transport systems and the roles of these systems in virulence; presents structural studies of siderophores, heme carriers, and iron transport proteins; discusses the ecology of siderophores and potential therapeutic uses of siderophores.
Download or read book Voltammetric Studies on Copper Lead and Cadmium Speciation in the Great Lake Waters written by Yefei Wu and published by . This book was released on 1998 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Trace Metal Speciation in Marine Waters by Competitive Ligand Equilibration solvent Extraction written by Lisa Ann Miller and published by . This book was released on 1994 with total page 506 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Speciation Analysis of Trace Metals in Natural Waters Using Vibrating Electrodes written by Zhaoshun Bi and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The speciation of trace metals plays a very important role in conditioning their biogeochemical cycles in the marine system. Their species are found to be strongly related to organic matters such as humic acids (HA) and fulvic acids (FA). This thesis aims to develop appropriate techniques to improve our understanding of the speciation of some trace metals, mainly in marine waters. Lead (Pb), cadmium (Cd) and chromium (Cr) which are widely used in industry were analytzed. The concentration of lead in uncontaminated seawater is between 10 and 100 pM, whilst in coastal waters it is higher at up to low nanomolar levels. Little is known about the chemical speciation of lead since it is difficult to be determined at picomolar levels. The work in this dissertation was to develop a suitable electrode and procedure to determine lead in seawater, with the objective that the electrode could be applied for in-situ measurement (without reagents) and for speciation. Several electrodes and materials were tested, including a solid bismuth rod and different microwire materials. Vibration was used to enhance mass transport, instead of solution stirring, to decrease detection limits and facilitate in-situ monitoring. The bismuth electrode was found to be suitable for monitoring lead in coastal waters: it is mercury-free and therefore environmentally friendly, but insufficiently sensitive for oceanic lead concentrations. Comparison of microwires of carbon, gold and silver showed that all of these bare electrodes give a signal for lead, but they suffer variable interference from cadmium, although this is minor if the cadmium concentration is lower than lead. A large improvement was obtained by coating the electrodes with mercury, which gave good peak resolution between cadmium and lead, and good sensitivity. The carbon and gold electrodes had good reproducibility and sensitivity when the mercury was renewed for each measurement. Once coated with mercury, the silver electrode formed amalgam with the silver which could not be completely removed. This electrode was thus not suitable to be used as a renewable mercury film electrode. However, as a permanently amalgamated silver electrode, it was found to have good sensitivity for lead, good separation from cadmium, and was stable for long time usage. This electrode, the silver amalgam microwire (SAM) electrode, was selected for further speciation study of Pb in oceanic waters. Optimum conditions for using the SAM electrode for trace lead detection in seawater involve the use of conditioning potentials. The limit of detection for lead was 4 pM lead in acidified seawater and 12 pM lead in seawater of pH 8. The higher limit of detection at pH 8 is due to the inorganic speciation at that pH. The SAM electrode was successfully used for pseudopolarography of lead to determine its organic complexation. This method was calibrated using model compounds and applied for the first time to estuarine, coastal and oceanic samples at natural concentrations of Pb. It was found that lead occurs mostly as a labile (reactive, organic) species, with a smaller fraction as a strongly organically bound species. The SAM electrode was also tested for chromium analysis using cathodic stripping voltammetry (CSV) in natural waters. Its detection limit is as good as the mercury drop electrode but reduces consumption of mercury.
Download or read book Marine Ecological Processes written by I. Valiela and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 690 pages. Available in PDF, EPUB and Kindle. Book excerpt: Marine Ecological Processes is a modern review and synthesis of marine ecology that provides the reader - particularly the graduate student - with a lucid introduction to the intellectual concepts, approaches, and methods of this evolving discipline. Comprehensive in its coverage, this book focuses on the processes controlling marine ecosystems, communities, and populations and demonstrates how general ecological principles - derived from terrestrial and freshwater systems as well - apply to marine ecosystems. Numerous illustrations, examples, and references clearly impart to the reader the current state of research in this field; its achievements as well as unresolved controversies.
Download or read book Marine Ecological Processes written by Ivan Valiela and published by Springer. This book was released on 2016-03-22 with total page 709 pages. Available in PDF, EPUB and Kindle. Book excerpt: The oceans represent a vast, complex and poorly understood ecosystem. Marine Ecological Processes is a modern review and synthesis of marine ecology that provides the reader with a lucid introduction to the intellectual concepts, approaches, and methods of this evolving discipline. Comprehensive in its coverage, this book focuses on the processes controlling marine ecosystems, communities, and populations and demonstrates how general ecological principles--derived from terrestrial and freshwater systems as well--apply to marine ecosystems. Global warming and increased eutrophication and wetland destruction in recent years has made the study of ecological processes even more important for the preservation of marine environments. This thoroughly updated and expanded edition will provide students of marine ecology, marine biology, and oceanography with numerous illustrations, examples, and references which clearly impart to the reader the current state of research in this field: its achievements as well as unresolved controversies.
Download or read book The Determination of Trace Metals in Natural Waters written by Thomas Summers West and published by Wiley-Blackwell. This book was released on 1988 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1993 with total page 1018 pages. Available in PDF, EPUB and Kindle. Book excerpt:
