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Electroanalytical instrumentation development for physico- chemical characterization of trace metals/marine environment

Reliable electrodes, hardware and corresponding software
flexible enough to allow several kinds of sensing techniques
to be used - greater precision in determination of trace
elements in aquatic systems

The project aims to develop an automated electrochemical system dedicated to the measurement of trace element speciation in the aquatic environment. The work includes aspects related to the development of reliable electrodes, hardware and corresponding software which provides flexibility so several kinds of sensing techniques can be used. The electrodes will be of efficient hydrodynamic design, whereas the hardware and software contains state-of-the-art digital techniques. Electrochemical techniques are highly sensitive and selective, permitting reliable measurements at very low metal concentrations, which is difficult to achieve by other methods. The sensitivity, precision and resolution of suitable potentiometric and voltammetric methods offer new dimensions with respect to the determination, speciation and physico-chemical characterization of various trace elements in aquatic systems. It is possible to obtain information on the type of metal species, the number of ligands as well as corresponding stability constants at concentration levels of 10 to minus 10 Mol dm to minus 3. Even though the electrode mechanisms involve mass transfer via diffusion and/or convection, the conditions of reversibility assure equilibrium between the interfacial concentrations of the oxidized and reduced components with corresponding electrode potential. Using electrochemical methods, the pitfalls common to other trace analysis procedures can be avoided giving due attention to contamination and alteration during sampling, sample storage and chemical treatment prior to analysis. Because the distribution of trace metal concentrations in sediments and biological materials highly depends on their concentration as well as on the chemical forms in waters these correlations will also be established for the Environmental Specimen Bank. Ultimately, this project aims to achieve in-situ measurement of trace element speciation in the aquatic environment, including polluted and unpolluted waters, which should be operated on-board vessels and/or a suitable platform. Prior to this a benchtop model will be developed which will measure speciation in batch samples. In addition to the hardware and software development, the project will also include: i) The application of theoretical model systems. Model parameters are to be evaluated from laboratory experiments and known physico-chemical properties of trace metals in the aquatic environment. This approach provides a means of the concentration and speciation of trace metals, as well as their biogeochemical reactivity in the aquatic system. The predicted chemical model composition will lead to refinements in the design of new analytical methods which can be most successfully applied to "in-situ" determination directly in the natural aquatic systems; ii) The predicted forms of trace metals in the previously mentioned steps will be retested by the field observations in seawater, estuaries and river waters; iii) The dynamics of the processes affecting biogeochemical distribution of trace metals among the marine compartments and an extensive survey of the distribution of trace metals between water, sediment and biological compartments of the collecting area of the Environmental Specimen Bank will be followed. Operationally defined speciation identifiers those chemical processes which should receive the most intensive study under "synthetic" laboratory conditions, and at field observations as well. This research will be realised in parallel and at each critical moment the "feed-back" mechanism will be applied to theoretical considerations, laboratory experiments and field observations leading to improved instrumental design. Special attention will be paid to the reliability of analytical data and to local conditions of known pollutants being released from anthropogenic sources to the aquatic system.
Acronym: 
ELANI
Project ID: 
493
Start date: 
01-06-1990
Project Duration: 
115months
Project costs: 
1 600 000.00€
Technological Area: 
Market Area: 

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