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).

Preface Uranium is a radioactive element and a heavy metal which is naturally occurring in ground and surface water. Although uranium is enriched in granites and gneiss ground water from these host rocks often shows low to intermediate uranium con centrations, while some ground waters from sandstone and carbonate aquifers show elevated uranium concentrations up to several hundred mg/1 without man made impact. On the other side, surface water contains increased anthropogenic uranium concentrations due to the intensive use of phosphate fertilizers and in mining areas due to mining and milling activities. Saxony and Thuringia both be ing states of the reunified Germany are probably an area where uranium mining activities have impacted the environment more severely than in any other part of the world. Thus, the federal government of Germany allocated huge amounts of money for the rehabilitation work, a unique proceeding without precedent in min ing history. In October 1995 the first international conference on Uranium Mining and Hydrogeology (UMM I) was held in Freiberg being organized by the Department of Geology at the technical University Freiberg by the support of the Saxon State Ministry of Geology and Environment. Due to the large scientific interest in the topic ofuranium a second conference (UMH II) took place in Freiberg in Septem ber 1998.

In recent years, radioactive contamination in the environment by uranium (U) and its daughters has caused increasing concerns globally. This book provides recent developments and comprehensive knowledge to the researchers and academicians who are working on uranium contaminated areas worldwide. This book covers topics ranging from the beginning of the nuclear age until today, including historical views and epidemiological studies. Modelling practices and evaluation of radiological and chemical impact of uranium on man and the environment are included. Also covered are analytical methods used for the determination of uranium in geo/bio environments. Some chapters explore factors which influence uranium speciation and in consequence plant uptake/translocation. Last but not least, several chapters provide approaches and practices for remediation of uranium contaminated areas.

This publication is one of the series of IAEA publications on the environmental behaviour of naturally occurring radionuclides. It outlines uranium behaviour in different environments, as well as its transfer to, and metabolism in, humans. The publication also provides concepts, models and data required for the assessment of the impacts of uranium on non-human biota. Assessing the environmental and health effects of uranium poses specific challenges because of the combination of different types of hazard and potential exposures. Therefore, both the radiotoxicity and chemical toxicity of uranium are considered in this publication.

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.

Nuclear Energy and the Environment provides an assessment, based on the opinions and findings of international experts in the field of atomic energy, of the environmental impact of the different stages of the nuclear fuel cycle. Chapters in the book cover different subjects in the use of nuclear energy such as the environmental impacts of energy production and use; the environmental impact of mining and milling of radioactive ores, upgrading processes, and the fabrication of nuclear fuels; none radiological environmental implications of nuclear energy; and the technology and environmental hazards of nuclear waste disposal. Nuclear scientists, environmentalists, ecologists, nuclear engineers, and policy makers will find the book interesting.