Broder J. Merkel

Britta Planer-Friedrich

To understand hydrochemistry and to analyze natural as well as man-made impacts on aquatic systems, hydrogeochemical models have been used since the 1960’s and more frequently in recent times. Numerical groundwater flow, transport, and geochemical models are important tools besides classical deterministic and analytical approaches. Solving complex linear or non-linear systems of equations, commonly with hundreds of unknown parameters, is a routine task for a PC. Modeling hydrogeochemical processes requires a detailed and accurate water analysis, as well as thermodynamic and kinetic data as input. Thermodynamic data, such as complex formation constants and solubility-products, are often provided as databases within the respective programs. However, the description of surface-controlled reactions (sorption, cation exchange, surface complexation) and kinetically controlled reactions requires additional input data. Unlike groundwater flow and transport models, thermodynamic models, in principal, do not need any calibration. However, considering surface-controlled or kinetically controlled reaction models might be subject to calibration. Typical problems for the application of geochemical models are: • speciation • determination of saturation indices • adjustment of equilibria/disequilibria for minerals or gases • mixing of different waters • modeling the effects of temperature • stoichiometric reactions (e.g. titration) • reactions with solids, fluids, and gaseous phases (in open and closed systems) • sorption (cation exchange, surface complexation) • inverse modeling • kinetically controlled reactions • reactive transport Hydrogeochemical models depend on the quality of the chemical analysis, the boundary conditions presumed by the program, theoretical concepts (e.g.

A Practical Guide to Modeling of Natural and Contaminated Aquatic Systems

Groundwater Geochemistry

Andrea Hasche-Berger

This book presents the results from the Uranium Mining and Hydrogeology Congress held in September 2005, in Freiberg, Germany. It addresses scientists and engineers involved in the areas of uranium mining and milling sites, clean-up measures, emissions of nuclear power plants and radioactive waste disposal, as well as political decision-makers. The topics covered are: impact on groundwater from radionuclide emission, analytical specification techniques, chemical toxicity, radioisotope plant uptake, microbiology, geochemical and reactive transport, case studies on active and abandoned uranium mines and milling sites, long-term storage of radioactive waste, passive in situ treatment techniques and risk assessment studies. The accompanying CD-ROM includes all papers in colour.

Mining Impact and Consequences

Uranium in the Environment

Uranium is an element to be found ubiquitous in rock, soil, and water. Uranium concentrations in natural ground water can be more than several hundreds μg/l without impact from mining, nuclear industry, and fertilizers. Considering the WHO recommendation for drinking water of 15 μg/l (has been as low as 2 μg/l before) due to the chemical toxicity of uranium the element uranium has become an important issue in environmental research. Besides natural enrichment of uranium in aquifers uranium mining and milling activities, further uranium processing to nuclear fuel, emissions form burning coal and oil, and the application of uranium containing phosphate fertilizers may enrich the natural uranium concentrations in soil and water by far. In October 1995 the first international conference on Uranium Mining and Hydrogeology (UMH I) was held in Freiberg being organized by the Department of Geology at the Technical University Bergakademie Freiberg by the support of the Saxon State Ministry of Geology and Environment. Due to the large scientific interest in the topic of uranium a second conference (UMH II) took place in Freiberg in September 1998. Furthermore, in September 2002 scientists working on the topic of uranium mining and hydrogeology attended the third conference (UMH III) which was jointly held together with the International Mine Water - sociation (IMWA) Symposium 2002. The reviewed papers and posters of the 2002 conference have been published by Springer entitled Uranium in the aquatic en- ronment (edited by Merkel, Planer-Friedrich and Wolkersdorfer).

Subject of the book is Uranium and its migration in aquatic environments. The following subjects are emphasised: Uranium mining, Phosphate mining, mine closure and remediation, Uranium in groundwater and in bedrock, biogeochemistry of Uranium, environmental behavior, and modeling. Particular results from the leading edge of international research are presented.

Uranium, Mining and Hydrogeology

Alireza Arab

This book is the collection of papers from the latest International Uranium Mining and Hydrogeology Conference (UMH VII) held in September 2014, in Freiberg, Germany. It is divided to five sessions: Uranium Mining, Uranium and Phosphates, Clean-up technologies for water and soil. Uranium and daughter nuclides and basic research and modeling. Each session covers a wide range of related topic and provides readers with up to date research and solutions on those matters.

Broder J. Merkel

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