Skip to main content

2006 | Buch

Uranium in the Environment

Mining Impact and Consequences

herausgegeben von: Prof. Dr. Broder J. Merkel, Dipl. -Geol. Andrea Hasche-Berger

Verlag: Springer Berlin Heidelberg

insite
SUCHEN

Über dieses Buch

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).

Inhaltsverzeichnis

Frontmatter
Long-term Aspects of Uranium Mining Remediation

After completion of the remediation of the legacy of uranium mining and milling for most of these objects and sites a continued monitoring will be necessary and some of these objects may require maintenance.

The main remediation objects in Saxony are waste rock piles, tailings ponds/deposits and underground mines. The monitoring and maintenance needs of the individual objects differ substantially and consequently the regulatory requirements (both type and extent of monitoring) placed on the individual objects will vary following an object-/site specific approach. Among the most sensitive monitoring parameters are the qualities of seepage and ground water. Another essential parameter is the monitoring of performance and maintenance of functionality of the covers placed on the waste rock piles and tailings to control radon exhalation and contaminated seepage. Unfortunately, there is no reliable database available for the long-term performance of the remediation measures and there has been no effort yet to develop such a database. To obtain a reliable estimate of the period of time needed for the active post remedial care, it is recommended to carry out studies on natural analogues. At present, the Saxon regulatory authorities demand a monitoring and maintenance period of 25 (radiation protection) rsp. 30 years (conventional waste regulations).

Provided the remedial measures taken prove to perform well, the monitoring effort will decrease with time. Considering the fact that the remediation measures implemented were designed for a 200 to 1000 years long stabile performance it is expected that little maintenance will be needed. However, singular cases of disruption, such as damages of cover cannot be excluded.

A most relevant issue in this respect is the funding of the long-term post remedial tasks. The owner responsible for the uranium sites and objects that were in legal possession of Wismut on June 30, 1990 is and will remain the Federal Government of Germany. For the former Wismut sites, which are legally owned by other parties, the responsibility for funding of long term monitoring and maintenance is in the hands of the actual owners.

Hartmut Biele, Stephanie Hurst
Returning the WISMUT Legacy to Productive Use

The prime goal of the Wismut environmental remediation (ER) project follows from the legal requirement to abate health risks, mitigate existing environmental damages and prevent future hazards.

The extent of remedial measures is derived by investigation of the object-specific remediation feasibility rather than by application of uniform standards. The ER workflow, unlike common civil engineering projects that are a linear succession of tasks, is an iterative process. Within the ER workflow, Conceptual Site Models (CSM) guide the optimization of designs and investigations while both operational works and environmental base line are monitored. The acquired data are collected and analyzed on a corporate wide level to provide decision-making support for senior management.

In the present, advanced stage of the Wismut remediation the reutilization of the reclaimed areas and objects is receiving an increased attention. There are no legal restrictions on utilization of areas, which received a complete clean up. Utilization of areas, waste rock piles and tailings ponds reclaimed for restricted use allows only settlement of industry and trades or forestation, however, exemptions are possible if the responsibility for long term monitoring and maintenance are satisfactorily ensured. A mutually beneficial integration of reclamation plans with the communal/regional development has been successfully practiced in two former mining towns, the first leading to rebirth of the health spa in Schlema and the second helping the preparation of the Federal Garden and Landscape Exhibition in 2007 (BUGA 2007) hosted by the towns of Ronneburg and Gera.

Manfred Hagen, Alexander Thomas Jakubick
The Effects of Weathering and Diagenetic Processes on the Geochemical Stability of Uranium Mill Tailings

In the present study, a detailed examination of tailings cores and pore waters, kinetic column test work and geochemical modelling was combined with results from earlier studies to examine the key processes governing the geochemical stability of the Ranger tailings. Conclusions drawn from the work clearly demonstrates that the solid state speciation and mobility of metals and radionuclides in the tailings pile are governed by the processes of oxidative dissolution of sulfide minerals, weathering of phyllosilicates and organic matter diagenesis.

Greg Sinclair, Graham Taylor, Paul Brown
Long term fate of uranium tailings in mountain areas

Common passive controls for uranium tailings include constructing thick earthen covers, protected by rock, over the waste. Earthen covers effectively limit dust and radon emissions and gamma radiation and, in conjunction with the rock covers, help stabilizing the tailings to prevent dispersion of the tailings through erosion or intrusion. In some cases, piles may be moved to safer locations (e.g. deep mines). However, the long term fate of uranium tailings in mountain areas is different from tailings in flat landscapes. Especially under humid climatic conditions the amount of rainfall is high as is the leaching and erosion potential. The uranium tailing Schneckenstein in the eastern part of Germany was chosen for a case study. The deposited uranium and other toxic elements will contaminate the downstream aquatic environment for thousands to more than ten thousand years depending on the scenarios chosen. Safeguarding the Schneckenstein tailing can be done over a few decades but gets much more difficult in the long term perspective. Because natural attenuation is unlikely to happen, enhanced natural attenuation or active measures have to be taken. Advantages and disadvantages of several options are discussed.

Broder J. Merkel
Rock phosphates and P fertilizers as sources of U contamination in agricultural soils

U concentrations were analyzed in a set of mineral fertilizers with and without P and compared to U concentrations in various organic fertilizers. Mean concentrations between 6 and 149 mg/kg U were found in P containing mineral fertilizers, while mean concentrations in mineral fertilizers without P were below 1.3 mg/kg U. Mean U concentrations in farmyard manures did not exceed 2.6 mg/kg U. As a consequence, an average P dressing of 22 kg/ha P would charge the soil with up to 17-61 g/ha U when added as mineral fertilizer but less than 10 g/ha when given as farmyard manure or slurry. Expected U uptake by crops is less than 1 g/ha U.

Sylvia Kratz, Ewald Schnug
Monitoring of natural radionuclides in soils as a tool for precision farming - methodical aspects

The use of natural radionuclide contents for the evaluation of soil quality data was tested by field logs and additional laboratory analyses on vertical profiles. The latter proved a well mixing of soil material in the uppermost 30 cm by ploughing. A mathematical procedure for the consideration of soil moisture and the determination of the “information depth” is presented and lead to good agreement between field and laboratory data.

Michael Tauchnitz, Detlev Degering, Carsten Pretzschner, Thomas Wonik, Juergen Boess
Electrophoretic characterization of thorium species in very dilute solutions containing humic acid

Electrophoretic mobility of thorium was measured in aqueous solutions (HClO4+ NaClO4, I = 0.01) as a function of thorium concentration (≪ 10-7 – 10-5 M), pH (2 – 10) and solution composition (Aldrich humic acid, NaHCO3) using free-liquid electrophoresis. Results have shown that negatively charged thorium humate complexes can prevail at pH 2 – 10 even in solutions containing very low concentration of humic acid (0.1 – 1 mg/L) and medium concentration of carbonates (0.001 M). The mobilities determined can serve for analysis of formation of the humate complexes in aqueous solutions and natural or wastewaters.

Petr Benes
Field Portable and Autonomous Immunosensors for the Detection of Environmental Contaminants

A monoclonal antibody that binds with high affinity to UO22+ complexed with the chelator 2,9-dicarboxyl-1,10-phenanthroline was used to develop a sensor-based assay for UO22+. The assay range for UO22+ was 0.5 to 25 nM (0.12 to 6 ppb). The average coefficients of variation in the assay was 2.2%. The immunoassay results were comparable to those obtained using the Kinetic Phosphorescence Assay. The versatility of this sensor platform was further demonstrated by the development of an immunoassay for caffeine.

Diane A. Blake, Haini Yu, Elizabeth A. James, Xia Li, Robert C. Blake
A method to measure arsenic readily released to pore waters from uranium mill tailings

A method to quantify the amount of readily released arsenic in uranium mill tailings was developed using a technique known as

E

quilibrium

P

artitioning

I

n

C

losed

S

ystems (EPICS). The method employs a gentle leaching solution that, except for its arsenic (As) concentration, is identical to the neutralized raffinate that contacts the tailings. Prior to implementation, the experimental design and mathematical approach were verified in geochemical models using PHREEQC. Laboratory experiments using tailings from the Athabasca Basin of Northern Saskatchewan demonstrated that As that could be readily released to pore waters is about 0.2 % of the total As in the tailings.

John Mahoney, Donald Langmuir, John Rowson
Impact of humic acid on the uranium migration in the environment

Redox properties of different humic acids (HA) were determined and the stability of the oxidation state of U(VI) in presence of humic acid was studied. Applying laser-induced photoacoustic spectroscopy a qualitative spectroscopic proof for the reduction of U(VI) to U(IV) by humic acid was obtained. By column experiments it was found that humic acid influences the transport of both, U(IV) and U(VI). In presence of humic acid both redox species migrate nearly as fast as the groundwater flow. In case of U(VI) humic acid exhibits a clear mobilizing effect. There are strong indications for a similar impact on the U(IV) migration.

Susanne Sachs, Gerhard Geipel, Jens Mibus, Gert Bernhard
Uranium speciation in two Freital mine tailing samples: EXAFS, µ-XRD, and µ-XRF results

We investigated the uranium speciation in a former WISMUT mine tailing, which was buried for 30 years under mine and construction debris. Chemical extractions, EXAFS, µ-XRD, and µ-XRF reveal two major U pools. The first with a relatively high potential mobility was identified as U(VI) sorbed to layer silicates by inner-sphere complexation; the second pool is represented by the relatively insoluble U(IV) minerals pitchblende and coffinite, and by the U(VI) solids uranyl hydroxide and vanuralite. Distribution between the two pools seems to be controlled by pH. Evidence for reductive precipitation of uraninite was found.

Andreas C. Scheinost, Christoph Hennig, Andrea Somogyi, Gemma Martinez-Criado, Reinhard Knappik
Site characterisation of the potential Natural Analogue Site Heselbach in Bavaria/Germany

The U-enrichment at Heselbach/Bavaria was checked to be a suitable Natural Analogue for transport processes in the far field of an underground repository. For that reason investigations at Heselbach were carried out to identify mobilization and immobilization processes of uranium and thorium in lignite and clay sediments. Geology, hydrology and radiochemistry were studied in order to get detailed information on these topics. Subsequent to the experimental investigations a uranium transport model has been developed.

Dagmar Schönwiese, Thomas Brasser, Ulrich Noseck
Speciation of Colloid-borne Uranium by EXAFS and ATR-FTIR spectroscopy

De-acidification of acid mine waters transfers dissolved uranium into a colloidal form. Spectroscopic studies on colloid-borne uranium obtained by simulation of mine flooding in the laboratory showed that matrix ions such as sulfate and silicate are not involved in inner-sphere surface sorption complexes of UO

2

2+

on ferrihydrite. At ambient air atmosphere, the data suggest the formation of ternary U(VI) carbonato surface complexes with either monodentate or bidentate coordination of carbonate and uranyl even at moderately acidic conditions. A revised model is proposed for UO

2

2+

sorption on ferrihydrite in the absence of carbonate.

Kai-Uwe Ulrich, André Rossberg, Andreas C. Scheinost, Harald Foerstendorf, Harald Zänker, Ulf Jenk
Influence of allochthonous plant litter on the fixation of Uranium in sediments

Plant litter of

Alnus glutinosa

(L.)

Gaertner

(alder) and

Quercus spec.

(oak) was investigated downstream an abandoned uranium mine tailing. Uranium concentrations in unwashed samples varied between 20 – 2000 µg*g

−1

*DM

−1

with differences between plant compartments: wood (app. 50 µg*g

−1

*DM

−1

), leaves (app. 200 – 400 µg*g

−1

*DM

−1

) and alder cones (app. 700 µg*g

−1

*DM

−1

). Compared to leaves from oak alder leaves contain significantly more uranium. Washing partially removes attached particles from the leaf surface. Uranium concentrations in unwashed alder leaves were usually smaller than in washed samples (<2000µg*g

−. 1

*DM

−1

).

Holger Dienemann, Claudia Dienemann, E. Gert Dudel
Advanced Investigations of Unconventional Uranium and Thorium Deposits by In-Situ μ-EDXRF Analysis

Exploration and identification of primary and secondary uranium and thorium enrichments can be facilitated by the μ-energy dispersive X-ray fluorescence (EDXRF) technique that allows the high resolution,

in-situ

, multi-element determination at the microscopic scale (10 to 100µm). EDXRF analysis is fast and useful for the identification of unconventional uranium and thorium deposits, the localisation of primary uranium and thorium minerals as well as secondary uranium- and thorium-bearing phases. A current project aims at the siting of uranium and thorium mineralisation in ores from the Witwatersrand Au (uraninite), Vergenoeg Fe-F (uraniferous monazite), and Palabora Cu (uranothorite) deposits.

Antje Wittenberg, Ulrich Schwarz-Schampera
Depleted Uranium (DU ) — Chemo- and Radiotoxicity

DU metal used for civil or military purpose reacts with water, undergoes radiolysis, dissolves and contaminates soil and ground water. DU is pyrophoric and burns on impact (3000°C). DU oxide particles (mainly U

6+

!) have a diameter of about 1.5 µm to 10 Å; 10 Å particles behave like a gas, carried by the air and travel long distances before they come down. DU is taken up by living organisms. Its α-radiation causes chromosome brakes (CB). A pilot study performed with Gulf War Veterans, originated by one of the authors (AS), did find 5.2 times more CBs on the average, with a maximum of 14 times higher. DU reaches all parts of an organism and leads to chemical and radiological damage.

Albrecht Schott, Richard A. Brand, Joachim Kaiser, Dietmar Schmidt
Effect of uranium and cadmium uptake on oxidative stress reactions for Phaseolus vulgaris

Bean seedlings were grown under controlled conditions on a Hoagland solution. Ten-day-old seedlings were exposed to 0, 0.1, 1, 10, 100 and 1000 µM U or 0.5 and 1 µM Cd. Following 7 days’ exposure, plants were sampled for determination of contaminant uptake, biometric parameters (shoot and root length, area of primary leaves, weight of shoot, root and primary leaves) and activity of enzymes involved in the plant’s anti-oxidative defense mechanisms. Generally we did not observe a significant difference in plant development between control and treated plants based on biometric parameters. Enzyme activities in roots were stimulated with increasing contaminant concentrations (though generally not significantly). However, for roots exposed to 1000 µM U, enzyme activity was generally significantly reduced. In shoots no significant difference in the defense mechanism between the treatments was observed.

Hildegarde Vandenhove, Ann Cuypers, May van Hees, Jean Wannijn
Coupled Microbial and Chemical Reactions in Uranium Bioremediation

The chemical composition of the water and sediment affects the extent that uranium is immobilized in a microbially active environment. This paper summarizes an integrated framework of coupled microbial and chemical reactions in uranium bioremediation. The research is aimed at improving selection, design and operation of uranium biotreatment systems that use natural organic material to support the microbial consortium. Highlights of experimental and modeling efforts are presented.

Linda A. Figueroa, Bruce D. Honeyman, James F. Ranville
Biotransformation of uranium complexed with organic ligands

Natural ligands can affect the bacterial metabolism and reductive precipitation of uranium. The metabolism of metal-organic complexes by bacteria depends upon the type of complex formed between the metal and organic ligand. For example, Fe(III) forms a bidentate complex with citric acid, and was readily metabolized by

Pseudomonas fluorescens

under aerobic conditions, whereas the binuclear complex formed between U and citric acid was recalcitrant. When supplied with an electron donor, anaerobic bacteria reduced U(VI)-citrate to U(IV)- citrate with little precipitation of uranium. X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectroscopy analysis showed that the reduced uranium was present in solution as mononuclear U(IV)-citrate complex. These results suggest that when reduced uranium is complexed with organic ligands, it can be mobile.

Arokiasamy J Francis
Changes of bacterial community structure of a uranium mining waste pile sample induced by addition of U(VI)

Several portions of a uranium mining waste pile sample were supplemented with different amounts of U(VI) in form of uranyl nitrate to investigate the interactions between the indigenous bacterial populations and U(VI). Selective sequential extractions showed that most of the supplemented U(VI) remained predominantly in weak complexes and hence bioavailable. Analysis of 16S rDNA clone libraries from untreated and U(VI)-supplemented samples revealed changes in the structure of the bacterial community.

Andrea Geissler, Andreas C. Scheinost, Sonja Selenska-Pobell
Sorption mechanisms and models. Their influence on transport calculation

Approaches for the prediction of transport of radioactive species in underground and surface water based on experimentally determined distribution coefficients (Kd) and sorption isotherms have a limited predictive capability, due to their sensitivity to many parameters. Models based on thermodynamic equilibrium can account for the influence of multiple parameters, but show important theoretical and experimental limitations, which restrict their predictive character for transport calculation.

Michel Fédoroff, Grégory Lefèvre
Simulation of propagation of leachate after the ISL mining closure

The solution formed in the process of uranium in-situ leaching propagates after the mining closure with the regional groundwater flow. Forecasting the migration of solution requires account of chemical reactions in the system of the acid solution and subsurface medium. The process of propagation of solution, and methods for this process modeling are considered in the paper. The Eulerian approach to calculation of reactions leads in the present case to significant numeral dispersion. In order to avoid this numerical effect, we have solved two independent passive mass transport problems. The final solution is a geometrical intersection of passive solutions.

Alexander Roshal, Dan Kuznetsov
Raffinate Neutralization Experiments at the McClean Lake Mill — Removal of Arsenic and Nickel

Uranium ores at the McClean Lake Operation in the Athabasca Basin of Northern Saskatchewan can produce elevated levels of arsenic (up to 700 mg/L) and nickel (up to 500 mg/L) in acidic (pH<1.5) spent leaching solutions (raffinates). Prior to neutralization, if necessary, ferric sulfate is added to tailings slurries to increase their Fe/As (molar) ratio to greater than 3. The slurries are then neutralized with lime to pH 4, and subsequently to pH 7–8. After neutralization, As and Ni concentrations average less than 1 mg/L. Solids from bench scale experiments demonstrate that As is associated primarily with scorodite and annabergite, with small amounts adsorbed onto or co-precipitated with ferrihydrite.

John Mahoney, Donald Langmuir, Maynard Slaughter, John Rowson
Dynamical Models for Uranium Leaching — Production and Remediation Cases

Leaching is a process of mass transfer between immobile mineral aggregate phases and mobile phases (reactive fluid). For such reactive transport phenomena a dynamical compartment model was developed. It combines solute transport in double porosity media with geochemistry (kinetics as well as thermodynamics described by PHREEQC). Besides several other applications, the model has been used to simulate quite different real-world scenarios related to uranium mining: (i) production case at Beverley mine and (ii) remediation case at Königstein mine.

Harald Kalka, Horst Märten, Rene Kahnt
Development of a 2-D modeling system for reactive transport in variable saturated porous media

In this paper we present a modeling approach developed for multicomponent reactive transport in partly or fully saturated media. The processes included in this modeling system comprise water flow and advective and/or diffusive transport of dissolved species, stationary and instationary gas phase diffusion, exchange between solutes and gaseous components, complexation and oxidation-reduction reactions in the aqueous phase, dissolution/precipitation reactions including sulfide mineral oxidation, buffering reactions, chemical weathering, and retardation processes (e.g. sorption).

Olaf Nitzsche, Guido Deissmann, T. Cramer
Modelling of uranium release from waste rock pile

Uranium release/uptake on material of waste rock pile No. 66 at Schlema-Alberoda (Saxony, Germany) was studied by both static (batch) and dynamic (column) experiments with the aim to obtain input data for modelling of uranium migration in the pile. Most of the experiments were carried out by radiotracer method using

233

U as the label. An ambiguous influence of humic acid (concentration 10 and 50 mg/L) on the migration of uranium was observed. The column elution experiments were modelled using PHREEQC that enabled to respect the kinetic character of the desorption process.

Dusan Vopalka, Petr Benes, Klara Doubravova
The Role of Groundwater-Stream Interactions for Uranium Fluxes in Fluvial Systems

Based on results from the Wismut region (Germany), this paper concentrates on hydrodynamic aspects of contaminant transport from uranium mining tailings deposits via alluvial groundwater into a receiving stream. The focus is on event-related hydraulic interactions between groundwater and surface water in the hyporheic zone, observed by long-term, quasi- continuous

in situ

measurements with electronic probes. Analyses of time series suggest that interactions between contaminated groundwater, porewater in channel sediments and stream water are highly dynamic, impacting on U-fluxes and mobility. Processes observed during flood events also question established views on run-off generation in streams.

Frank Winde
Long-term performance of reactive materials in PRBs for uranium remediation

Elemental iron (Fe

0

) and hydroxyapatite (HAP) were evaluated as reactive materials in PRBs for uranium remediation. Laboratory experiments were carried out and a pilot-scale reactive barrier with Fe

0

was installed in Pécs (Southern Hungary). Results of 2.5 years of operation are reported. The PRB has a considerable influence on groundwater composition: uranium concentrations decrease from 900 µg/l to <10 µg/l, TDS drop from 1,000 mg/l to 500 mg/l.

Vera Biermann, Franz-Georg Simon, Mihály Csővári, József Csicsák, Gábor Földing, Gábor Simoncsics
Uranium leaching during short term application of pit-water on a carbonate containing soil in the Mendoza province of Argentina

Pit-water from an Uranium (U) mine in San Rafael, Argentina, was applied to soil columns in a short-term experiment to evaluate retention of U. The mine soil was coarse-textured, with pH

(KCl)

7.7 and a carbonate content of 6%, which may favour the formation of uranyl-carbonates. Triple superphosphate (TSP) and ground plant material were added as amendments to reduce U mobility in soil. Plants were sown to study their effect on U leaching. > 99 % of the U applied was retained by the soil. Plant growth increased U mobility but also reduced leachate volumes through evapotranspiration. TSP increased plant biomass, reducing the mass of U leached, while ground plant material enhanced leaching of U.

Juan Pablo Bonetto, Silvia López, Silvia Ratto, Valeria Schindler, Ewald Schnug
Simultaneous In-Situ Immobilisation of Uranium and Arsenic by Injectible Iron and Stimulated Autotrophic Sulphate Reduction

The combination of injectible grey cast iron (gcFe) and nano-scale iron (naFe) corrosion with autotrophic sulphate reduction (aSR) for simultaneous U and As immobilisation was investigated in column experiments. NaFe resulted in an intensive corrosion, the formation of a homogenous reactive zone, a distinct aSR and complete U and As immobilisation. At the gcFe column, a particle displacement resulted in the formation of reactive gcFe clusters, which were partly bypassed by the influent groundwater. Nevertheless, the lasting gcFe corrosion caused a complete As, but only partial U immobilization.

Diana Burghardt, Elisabeth Stiebitz, Kai Knöller, Andrea Kassahun
The modeling system for finding the optimal mining and wastewater discharge

The paper introduces a tool that enables to improve decision process and specify way and conditions of wastewater disposal. The tool is an information system for water treatment. The system is fully configurable so that user of the system can assign all the relevant ingredients of contamination and kinds of waters. Mixture of waters is confronted to limits allowed for selected checkpoints and to prescripts of contaminant volumes for nature water streams. The overall wastewater disposal admissibility is evaluated. The additional parts of the system are optimizing module and a graphical module. The optimization is performed in accordance to the selected optimization criterion. The system is realized so way that it suits wide aggregate demand for a wastewater treatment on different levels, where the problem is currently solved (economic level, legislative level, ecology institution).

Jan Novák, Hana Čermáková, Jiřina Královcová
Pilot Scale RAPS-System in Gernrode/Harz Mountains

This paper presents experimental studies and first results of a pilot scale RAPS-treatment system to reduce the high iron content of an iron rich mine water. In 1985, economic reasons caused the closure of the fluorspar mine “Hohe Warte” near Gernrode in the German Harz Mountains. Though remediation works were conducted in the preceding years, mine water is currently flowing out freely of the dewatering adit and is impacting the environment and the receiving brook. The mine water is characterised by low pH-values, high conductivities and contains considerable amounts of iron, manganese, and arsenic. Annually, the mine discharges 0.7 Mio m

3

of mine water with 7.8 tons of iron, 3.8 kg of manganese, 13 kg of arsenic, and 2,5 kg of uranium. Therefore, the discharging mine water has a great potential to affect the quality of the receiving streams and resulted in a decrease of biological diversity. Based on hydrogeological and hydrochemical investigations, a passive treatment system would be able to treat the mine water. In February 2003 a pilot system was installed near the dewatering adit consisting of a settlement pond, a RAPS system (reducing and alkalinity producing system) and a constructed wetland. It could be shown that this passive system was able to treat an aliquot of the mine water down to ecologically acceptable standards.

Andrea Hasche-Berger, Christian Wolkersdorfer
Passive Biological Treatment Systems of Mine Waters at WISMUT Sites

Water treatment is an important component of WISMUT’s remediation activities at uranium mining and milling sites in Eastern Germany, from both an environmental and financial perspective. In most cases, uranium, radium and arsenic are the main contaminants, while at some sites, nickel and other nonradioactive metals are present too. Passive systems are an attractive alternative to conventional treatment facilities. Numerous approaches have been developed that use natural processes to remove metallic contaminants from mine and seepage water. However, implementing biological water treatment systems is still often regarded as “tricky”, and scepticism as to their effectiveness and stability is prevalent among practitioners, the public and, perhaps most importantly, regulators. This paper addresses the regulatory and compliance issues, some of the key issues in the development and construction of such systems, and discusses practical examples of passive mine water treatment systems that have been completed and evaluated by WISUTEC already.

Annette Küchler, Gunter Kiessig, Christian Kunze
Uranium Fate in Saturated Porous Media under Arsenic, Iron and Bacteria Influence: The Role of Potassium

Uranium (U) and arsenic (As) of leachates from mine tailing dumps are a notorious cause of environmental concerns. Iron (Fe) oxides and metal reducing bacteria are well known immobilizers of U and/or As in unsaturated and saturated porous media. This paper describes investigations on geochemical controls of U fate under the influence of As, Fe and bacteria. Batch experiments were performed in glass test tubes using natural iron minerals and scrap metallic iron in setups designed to ascertain the kinetics and the influence of arsenic and iron. The effect of the background electrolytes NaCl or KCl and related ionic strengths were also considered. The experiments suggest prevalent role of the scrap iron’s corrosion products but also of those of potassium (K) and calcite. Similarly, four glass columns (40 cm height, 2.4 cm diameter) were packed in weight/weight proportion of 90% sand and 10% scrap Fe (0.2–0.8 mm). Two columns without metallic Fe were filled with 50% sand and 50% glass beads and 100% sand respectively. Five columns including a control were leached at 0.12–0.39 ml/min with a 0.01M KCl or NaCl background electrolyte spiked with 0.05mM of U (11.9mg/l) and As (3.7mg/l). Two columns were leached with Schneckenstein (Saxony, Germany) Uranium tailings leachate upgraded to 0.05 mM U and As and a parallel continuous feed of a solution of 1mM glucose. Effluents samples collected regularly for a total of 77 pore water volume (5 litres) show fixation of more than 95% of both U and As in all columns were scrap Fe was present. The control column, however, has shown an unexpected fixation of both U and As between 90–95% suggesting precipitation/co-precipitation of both U and As through sparingly soluble minerals such as Abernathyite KUO

2

AsO

4

. 4H

2

O as predicted by PHREEQC (LLNL database). Thus, K may be an efficient and cost effective amendment for immobilizing both U and As in contaminated porous media through precipitation/coprecipitation mechanisms if As and U are present at high concentrations. However, the reduction of both arsenic and uranium is limited by the solubility product of Abernathyite maintaining uranium and arsenic concentrations in the range of tens of µg/L. Potassium as an essential intracellular nutrient might also play a double role of enhancing bacteria mediated biotransformation and immobilization of uranium and arsenic.

Clement Mbudi, Broder J. Merkel
Interaction of uranium from seepage water with hydroxyapatite

Column experiments (in a quartz matrix) assisted by batch experiments helped to quantify and characterize the uranium(VI) retardation by hydroxyapatite, regarded as a highly efficient component of reactive barrier concepts for (radio) toxic contaminants. The sorption of uranyl ions onto phosphate groups is as important as their sorption onto silanol groups, outweighing the low phosphate content. In column experiments retardation factors ranging around 30 were observed. The elution of uranium is governed by two processes of different rate (and probably reversibility) which is consistent with the spectroscopic findings.

Jens Mibus, Vinzenz Brendler
Integrated water protection approaches under the WISMUT project: The Ronneburg case

At WISMUT’s Ronneburg mine site since 1991 a combined remediation strategy has been realised, which consists of the following central elements: clean-up of operational areas, backfilling of the open pit mine with waste rock from the surrounding piles, flooding of the underground mine and construction/operation of technical water management systems. This remediation approach can be characterized by a number of environmental benefits which include the termination of water quality problems caused by the waste rock piles which were originally spread over a large area, the immobilization of toxic substances in the area of the underground and the open pit mine and the termination of surface water pollution by the discharge of effluents from the mine drainage system. These effects enabled WISMUT to minimize the additional construction and operational costs for technical water management and treatment systems which are, however indispensable for the successful completion of the closure work.

Michael Paul, Manfred Gengnagel, Delf Baacke
The results of the pilot plant study for arsenic removal
Hamidur Rahman, Yasumoto Magara, Satoshi Miyabayashi, Yasuyuki Yagi
Uranium in natural wetlands: a hydrogeochemical approach to reveal immobilization processes

In the former uranium mining area in Eastern Germany small natural wetlands were studied with respect to there removal efficiency for uranium. Within this project we investigated surface water samples, plant material, sediment cores and pore waters to understand hydrogeochemical processes in natural wetlands, which are assumed to be dominant factors for uranium accumulation. Uranium contents of the wetland substrates are enriched up to 3000 times compared to pore water values. Autoradiography and SEM/EDX studies revealed evenly dispersed uranium in the wetland soils. Uranium appears to be mainly sorbed to organic matter, as also shown by sequential extractions. There is no evidence for precipitation of uranium minerals.

Angelika Schöner, Martin Sauter, Georg Büchel
Removal of heavy metals, arsenic and uranium from model solutions and mine drainage waters

The aim of this work was to study the suitability of a new ceramic-based biomass, called Biocer. Different carrier materials were developed to investigate and improve the mechanical and hydrolytical stability of the Biocer material. In this work, the different materials should be compared. The biosorption of the materials was realised in batch equilibrium and first column experiments. First preliminary experiments with the Biocer I material in columns with real mine drainage waters resulted in a good removal of uranium and other heavy metals.

Gunnar Horak, Christian Lorenz, Karsten Steudel, Sabine Willscher, Wolfgang Pompe, Peter Werner
Passive Treatment of Minewater at the Schlema-Alberoda Site

A pilot scale constructed wetland for treatment of seepage water from uranium mining was planned, built and operated. The pilot plant was designed for treatment of 5 m

3

per hour. The system consists of 4 basins and 1 lagoon. The objective of the project was the investigation of the long-term stability and robustness of passive water treatment systems. The feasibility of treatment of seepage water from uranium mining in constructed wetlands was proven by the operation of the pilot plant. A series of robustness investigations was conducted; including the operation during long lasting frost periods, under increased hydraulic load and under high carbon load. By using a tracer the hydraulic characteristics of the basins was tested. The control of the wetland is very complex due to different redox condition necessary for removal of arsenic (aerobic) and uranium (anaerobic). Additional information for an increased robustness of the system was derived from the operational results.

André Gerth, Anja Hebner, Gunter Kiessig, Anja Zellmer
Decommissioning of Uranium mill tailings ponds at WISMUT (Germany)

Approximately 577 ha of Uranium mill tailings ponds containing approx. 154 Mio. m

3

of mill tailings were left as part of the legacy of the uranium mining and milling in Eastern Germany. The decommissioning of these tailings ponds belongs to the most challenging tasks of the entire Wismut remediation project. The remediation activities started in 1990 with defence measures against acute risks, environmental investigations and development of first site specific remediation concepts. Resulting from the site specific remediation concepts WISMUT GmbH decided to prepare for dry decommissioning in situ for all of the mill tailings ponds. Dry decommissioning of tailings ponds consists of the following basic decommissioning steps: expelling of pond water and seepage catchment including water treatment; interim covering of exposed tailings surfaces including dewatering of unconsolidated fine slimes by technical means; re-contouring of dams and ponds and final covering including landscaping and vegetation. This paper presents the development and the principal design of the decommissioning of the large Uranium mill tailings ponds and the progress achieved by WISMUT.

Albrecht Neudert, Ulf Barnekow
Characterizing Uranium Solubilization Under Natural Near Oxic Conditions

A solubilization study for in total 782 days using not shaken batch experiments with uranium-bearing rock and three natural carbonate minerals was conducted to characterize uranium (U) leaching under oxic conditions. Results showed that aqueous U concentration increased continuously with a solubilization rate of 0.16 ▭gm-2h-1 for the first 564 d (1.5 y). After 1.5 y, U concentration reached a maximum value (saturation) and decreased afterwards. The saturation concentration of 54 mgL-1 (mean value) was influenced to variable extent by the presence of carbonate minerals. Dissolution/precipitation, adsorption or ion exchange processes appear to control U solubilization.

Chicgoua Noubactep, Dirk Merten, Till Heinrichs, Jürgen Sonnefeld, Martin Sauter
The optimal strategy of cleaning of fucoid sandstone
Michal Balatka, Hana Čermáková, Jan Novák, JiřÍ Mužák
A novel technology for sealing and immobilization — the use of precipitation processes from supersaturated solutions

Mineral forming solutions can be prepared by using of special precipitation inhibitors. These are compounds allowing the mixing of solutions which are incompatible under normal conditions, for example BaCl

2

and Na

2

SO

4

solutions or lime suspensions and diluted sulfuric acid. Clear, temporary stable solutions are obtained. If these are used as grout, directed precipitation takes place in the flow paths. The paper summarizes the fundamentals of the technology and gives an overview about the characteristics of gypsum and BaSO

4

forming solutions. Their immobilization effect was proven by column tests, which are discussed in detail.

Gerald Ziegenbalg
Variation in heavy metal uptake by crop plants

Relative to heavy metal (HM) excluder plants (French bean, lupin, maize, cereals), HM sequestering crops (buckwheat, beet root species) accumulate up to the 18-fold concentrations of As, Cd, Cr, Cu, Ni, Pb, and Zn as a sum in their shoot tissue. Soil amendment with nitrogen increased HM uptake further. This is a novel treatment to make continuous phytoextraction technologies more efficient without increasing the soil’s leaching rate.

Hans Bergmann, Klaus-Dieter Voigt, Bernd Machelett, Gerhard Gramss
Phytoavailability of uranium: influence of plant species and soil characteristics

Five plants (Maize, Indian mustard, Wheat, Pea and Ryegrass) with reported differences in uranium uptake were screened in a greenhouse experiment for their uranium soil-to-plant transfer from two soils. Soils were spiked with

238

U and were distinct in uranium availability characteristics. It was investigated if variability in uptake could be traced back to a different interaction of plants with the soil matrix or to different organic acid concentrations in the soils after plant growth. Clearly distinct transfer factors were obtained between soil groups which could be traced back to a difference in uranium availability between soils. However, within a soil group, there was no relation between (plant-induced changes in) soil characteristics and the transfer factors observed. The mechanisms by which the plants inhibit or promote root-shoot transfer seemed more important than soil characteristics to explain the difference in uranium transfer factor observed.

Lise Duquène, Hildegarde Vandenhove, Filip Tack, Ellen van der Avoort, Jean Wannijn, May van Hees
Uranium accumulator plants from the centre of Portugal — their potential to phytoremediation

The strategies of metal tolerance developed by several plants that enable them to survive in contaminated and polluted sites allow that some of them may accumulate significant concentration of a specific element. The work presented here is part of a larger on going study about the uraniferous geochemical province of Central Portugal, and it focus only in a preliminary description of results obtained with aquatic plants that show potential for phytoremediation. We have observed that

Apium nodiflorum, Callitriche stagnalis, Lemna minor

and

Fontinalis antipyretica

accumulate significant amounts of uranium, whereas

Oenanthe crocata

inhibit the uranium uptake.

João Pratas, Nelson Rodrigues, Carlos Paulo
Soil treatment with nitrogen facilitates continuous phytoextraction of heavy metals

NH

4

Cl was the optimum N compound to make soil heavy metals more plant-available but less leachable, and to increase biomass production, root uptake, and translocation to the shoot of Cd, Co, Cu, Mn, Ni, and Zn in Chinese cabbage. Their total weight in the shoots of higher biomass increased to 765 %.

Gerhard Gramss, Georg Büchel, Hans Bergmann
Possible biomineralisation of uranium in Lemna gibba G3

We investigate biomineralisation of U(VI) accumulated in

Lemna gibba

G3 under laboratory conditions. Almost 50.3±11.2 % of uranium was eluted from biomass resulting into 243.5±111.7 mg Kg

−1

, and 308.9±189.3 μg L-1 in eluates in a 30 minutes deportation experiment. No further uranium losses or concentration increase in aliquot were observed in weekly analysis of soaked biomass for 5 weeks. Phase Contrast and Scanning Electron Microscope shows crystal formation in and on the fronds. Energy dispersion X-ray showed that the crystals contain uranium and elements that support the phenomenon of metal oxalate formation in Lemna sp. Uranium was likely fixed culture as uranyl oxalates species in

Lemna gibba

. Hence, further studies are required to determination uranyl oxalates species structures and ascertain the biomineralisation.

Martin Mkandawire, E. Gert Dudel, Carsten Müller
Accumulation of natural radionuclides in wooden and grass vegetation from abandoned uranium mines. Opportunities for phytoremediation

The survey is focused on accumulation of uranium, radium and the concomitant heavy metals in forest and grass vegetation growing upon uranium waste rock dumps.

In the report are presented the final results from long-term investigations of factors on which depends the accumulation of natural radionuclides and heavy metals in vegetation.

Shown are the results of greenhouse vegetational experience with grasses and sorbents. Tracked are main growth indexes (increase in height and thickness and increase in volume) in the species of black pine-tree (Pinus nigra Arn.) and white pine-tree (Pinus sylvestris L.).

Rossitsa Petrova
Study of radiophytoremediation on heavily polluted area in South Bohemia

A phytoremediation study was performed on the area of the old uranium mill tailings waste depot of a former uranium ore reprocessing factory in South Bohemia. The distribution of

226

Ra in contaminated soil was found to be extremely variable (from 7 to 32 Bq

226

Ra/g of DW). No direct relation was proved between plant species characteristics and their radioactivity content. The results showed a great range of variation in the accumulation of

226

Ra by the plant species found. The highest activity of

226

Ra was found in

Potentilla reptans

(4.09 Bq

226

Ra/g of DW),

Mentha arvensis

(4.00 Bq

226

Ra/g of DW), and

Daucus carota

(3.70 Bq

226

Ra/g of DW). The greenhouse and small scale field experiments show

Cannabis sativa

“Beniko” as a good potential accumulator of activity

226

Ra.

Petr Soudek, Sarka Valenova, Tomas Vanek
Localisation of uranium in roots by chemical extractions and by a short term uptake study. Influence of phosphate.

Pea roots were exposed to nutrient solution containing 25 µmol L

−1

of uranium in presence or absence of phosphate. The uptake of U was followed during the first 90 minutes of exposure. Fifty percent of the uranium was removed after 45 minutes and after between 60–90 minutes in absence and in presence of phosphate respectively. After 24 hours exposure, root were extracted, to remove uranium from the root apoplasm. Copper extracted similar amounts of uranium than EDTA for root exposed to a solution with phospate while copper extracted only 18% of uranium extracted by EDTA for root exposed to a solution devoid of phosphate. Phosphate decreased the availability of uranium to roots of pea. The presence of phosphate decreased also the amounts of uranium extracted.

Anne Straczek, Jasmine Dams, Hildegarde Vandenhove
Study of the chemical leaching of uranium from several mineralogical layers

The purpose of the present work was to study the oxidation of uranium species coming from different samples of some Romanian uranium ores at U(VI), in the presence of the following oxidizing agents: KMnO

4

/H

2

SO

4

, H

2

O

2

and royal water. It was established that the highest capacity of leaching is shown by KMnO

4

/H

2

SO

4

that achieved values of ca. 100% in about seven days. This chemical reaction was explained through the chemical and mineralogical composition of the studied samples.

Marian Raileanu, Rodica Calmoi, Catinca Simion, Gabriel Barbir, Alexandru Cecal
Environmental Management and Optimization of In-situ-Leaching at Beverley

Heathgate Resources Pty. Ltd. operates the Beverley Uranium Mine in South Australia (SA) by utilizing a moderately acidic In-situ leaching (ISL) technology, which is best in terms of minimizing surface disturbance. The paper describes the optimization of ISL operation with regard to both leaching efficiency and minimization of environmental impacts in the framework of relevant approvals and regulations.

Horst Märten
Favourable Factors for Uranium Mineralization in District Surguja, India

In view of world analogy for the favorable sites of Uranium mineralization in the sedimentary Proterozoic rocks, the ENE-WSW trending Narmada-Son Lienament/ fractured basement of Proterozoic Arachean age overlain unconformably by the Gondwana Super Group sandstones of Mesozoic to Lower Permian age in District Surguja offers an ideal site for the Uranium mineralization. Some of the favourable factors, namely, the nature of basement rocks present in the area, surrounding rocks, type of environment which favours the mineralization and tectonic features etc have been discussed.

S. K. Sharma
Long-term aspects of waste rock piles and tailing in Kyrgyzstan

The complex of man-caused and natural factors, determining a high risk of long-term storage of radioactive waste on the territory of Tien-Shan is analysed. This complex involves the large-scale levels: regional geodynamical position; local tectono-geophysical, hydro-geological conditions; petrophysical rock properties on the sites of construction of tailings. The effective control of both lithosphere and tailing condition is possible by using geophysical methods.

Yuriy Aleshin, Isakbek Torgoev
Risk assessment of emergency situation initiation in the uranium tailings of Kyrgyzstan

The present report represents the results of works done for risk evaluation, which was made by analysis of potentially hazardous phenomena and conditions in the Alpine Uranium tailing Tuyuk-Su in Min-Kush village in Kyrgyzstan. Short description of this tailing environmental influence is also provided. The most ecologically hazardous is the real scenario of Tuyuk-Su tailing collapse as a result of this narrow river valley blockage, where the tailing is located, by landslide masses. Some recommendations for risk mitigation of catastrophic situation initiation are given.

Isakbek Torgoev, Yuriy Aleshin, Dmitriy Kovalenko, Pavel Chervontsev
Environmental regulation of uranium mining in Australia

Uranium mining has been taking place in Australia more or less continuously since the late 1930s but it really only came to the fore after 1945. Environmental protection legislation did not become established until 1976. As a consequence the environmental management of many early uranium mines was virtually non-existent and a number of adverse environmental impacts were recorded. p]The development of modern uranium mines, essentially since 1970, has been associated with two major issues: a growing understanding by industry and regulators of the need for environmental management and pollution control, and increasing community pressure for minimisation of adverse environmental impacts from all mines. Under these conditions Australia has developed regulatory regimes for uranium mines which incorporate some of the highest environmental standards in the world. This paper sets out to describe how the current uranium mines in Australia are regulated from an environmental viewpoint. The discussion deals with the regulation of underground, open cut and in-situ leach uranium operations in climatic zones varying from the wet-dry tropics to arid deserts. The regulatory regimes involve a complex mix of federal and state governments as well as traditional Aboriginal Landowners and other significant stakeholders. The paper sets out how these different agencies and organisations work together to ensure that uranium mines are operated in accordance with the expectations of the community in terms of their environmental, health and safety expectations whilst maintaining economic viability and operational efficiency.

Peter Waggitt
Former mining activities influence Uranium concentrations in the Elbe river near Magdeburg

This paper presents data of dissolved and total uranium concentrations after the 2002 flood event, at a flood in spring 2003, and during an extreme low water period 2003 in the river Elbe. In addition, data from several Saale river tributaries are evaluated. The results reveal the remaining pollution potential in the Mansfelder Land catchment that requires the development of remediation strategies.

Martina Baborowski, Margarete Mages, Carola Hiltscher, Jörg Matschullat, Helmut Guhr
Modelling Underground Ventilation Networks and Radon Flow for Radiological Protection Using VUMA

In uranium mines radon (

222

Rn) is of major concern for occupational health and the concentration has to be maintained within allowable limits. It is necessary to ensure safe working conditions and occupational health in advance by predicting the expected radon concentrations throughout the underground network and to provide evidence of this in licensing procedures (SSK 1997; IAEA 2004).

This can be achieved by numerical modelling of the ventilation network as well as the contaminant transport. All flow modelling efforts require the geometrical setup of an underground network and validation. The resulting model of the network can then be used for the development of ventilation strategies with regard to contaminant transport.

This study presents the modelling of radon flow in a ventilation network of a hypothetical uranium mine using VUMA. The ventilation is modelled using the “fixed flow” option. The radon concentrations are computed using non-sitespecific but realistic radon sources. Sensitivity is studied by varying the locations and exhalation rates of radon. The results are evaluated in terms of radon concentrations and compared to allowable limits.

The results of this study using VUMA show its applicability for modelling radon flows. VUMA may be used to assess the requirements for ventilation strategies to comply with regulations for occupational radiation protection. Additional conclusions can also be drawn for effective energy management as well as safe working conditions in mines.

Guido Bracke, Hakan Alkan, Wolfgang Müller
Integration of Life Cycle Assessments in the decision-making process for environmental protection measures and remedial action at active and abandoned mining sites

Life-Cycle Assessments (LCA) have increasingly been used to evaluate the environmental performance of industrial processes and products and have been employed as a basis in decision making processes in the public and industrial sector. In contrast, assessment methodologies for environmental protection measures and remediation measures with respect to their consumption of natural resources are generally poorly developed. In this paper a methodology for LCA of environmental protection measures and remedial actions is suggested, using the remediation/reclamation of mining sites as an example.

Stefan Wörlen, Stephan Kistinger, Guido Deissmann
Simulation of Liberation and Transport of Radium from Uranium Tailings

The uranium tailings contain a large amount of radium, besides other radionuclides like uranium, thorium, polonium and lead. The transport and fate of radionuclides in groundwater are assumed to follow the theoretical approach represented by the basic diffusion/dispersion — advection equation. Our algorithm uses the analytical solution for the one dimensional steady-state transport problem of a reactive substance with simultaneous retardation and radioactive decay. The final output is the radionuclides concentration in a hypothetical well location as function of the elapsed time.

Maria Lurdes de Dinis, António Fiúza
Preliminary Hydrogeologic Investigations of Nubia Sandstone and fractured Basement Aquifers in the Area between El Shalateen and Halayeb, Eastern Desert, Egypt

El Shalateen-Halayeb triangle is a promising district for tourism and agricultural development. Pre-Miocene rocks (fractured basement and Nubia sandstone) represent the main water-bearing formations in the investigated area. Rainfall and occasionally flash floods represent the main sources of recharge. Groundwater occurrence and movement in basement aquifer is mainly controlled by the structural elements, where interaction between fractures and intrusive dykes reflect a good environment for groundwater entrapment. In fractured basement aquifer, the transmissivity ranges from 2.75 m

2

/day to 784 m

2

/day. Such wide variation could be attributed to the lateral facies changes as well as the impact of the complicated structural setting. Nubia sandstone is detected as a water-bearing in Abraq, Abu Saafa and EL Dif localities, its transmissivity varies from 2.72 m

2

/day to 72.4 m

2

/day. Poor potentiality of aquifers is mainly due to high channel gradient, which gives no chance for groundwater replenishment. Regionally, the direction of groundwater flow is mainly restricted by the variable hydraulic gradients from locality to another.

Twenty-three groundwater samples were collected and chemically analysed. Groundwater salinity of basement aquifer varies from 438 mg/l to 10409 mg/l, reflecting a wide variation in groundwater quality from fresh to saline. The groundwater quality of Nubia sandstone aquifer varies from fresh to brackish, where the 620 Yehia L. Ismail, Esam El Sayed, Mohammed A. A.Gomaa Risk assessment studies salinity ranges from 459 mg/l to 1292 mg/l. In basement aquifer, the type Cl-Na is dominant, while in Nubia sandstone aquifer, HCO

3

-Na and Cl-Na water types are recognized. In basement aquifer, the groundwater is mostly characterized by permanent hardness (except Nos. 1, 6 & 13 have a perfect temperary hardness). In Nubia sandstone aquifer, the groundwater is mainly characterized by temporary hardness. In basement groundwater, Cl is the most correlated anion with salinity (R

2

= 0.9615), and Na is the most correlated cation with salinity (R

2

=0.9153). In Nubia sandstone groundwater, SO

4

is the most correlated anion with salinity (R

2

= 0.7573) and Na is the most correlated cation with salinity (R

2

= 0.8578). Groundwater quality was evaluated for different uses and some recommendations were given.

Yehia L. Ismail, Esam El Sayed, Mohammed A. A. Gomaa
Development of water-borne radioactive discharges at WISMUT and resulting radiation exposures

Since 1989, collected discharges of uranium loads via the water pathway have dropped from a total of 27.5 tonnes to less than 3 tonnes in 2004. Commissioning of modern water treatment plants has greatly contributed to this achievement. Resulting site-specific effective doses to the population are significantly below 1 mSv/a. However, diffuse discharges of contaminated seepage or percolation waters from tailings ponds may cause doses in the order of 1 mSv/a. Capping operations are instrumental in reducing the diffuse discharge of radioactive effluents via the water pathway to a reasonably low level.

Peter Schmidt, Thomas Lindner
Radionuclide Data for Geothermal Prospection — A Contribution to the Geothermal Resources Map of Saxony

Geothermal energy is one of the long term perspectives in the field of renewable energy. A research and development project was started to evaluate the deep geothermal potential in Saxony, East Germany. The investigation is a contribution to the geothermal resources map of Saxony. The geological setting of Saxony is characterised by a variety of solid rocks. A lot of them are containing remarkable radionuclide concentrations, so they are source of radioactive heat generation due to radioactive decay. This source was investigated quantitativly.

Petra Schneider, Helmut-Juri Boeck, Thomas Lange
Contaminated Sediments in the Elbe Basin and its Tributary Mulde

Data from the Elbe River and its tributaries indicate, despite extensive improvement in water quality since reunification, that the sediment situation of many priority pollutants has not reached an acceptable level. The risks for downstream sites, especially the port of Hamburg, the lower part of the tidal river Elbe and the North Sea will persist in future. In practice, the catchment-wide assessment of contaminated soil and sediment should be identified and valued for acquiring a management plan for the EC Water Framework. The focus will be the on the tributary Mulde.

Petra Schneider, Heinrich Reincke
Lead isotope ratios as a tracer for contaminated waters from uranium mining and milling

The elevated uranium concentrations of the ores of the Witwatersrand and the great age of the deposits have resulted in the development of extremely radiogenic lead isotope ratios. These ratios are reflected in the wastes and effluents generated by mining activities and may be used for the identification and tracing of Witwatersrand-sourced contamination. Fine sediments act as accumulators of heavy metals in the streams and rivers downstream of mining activities. Analysis of the lead isotopic compositions of these sediments can be used to identify and apportion the sources of this contamination.

Henk Coetzee, Mari Rademeyer
Moab, Utah, UMTRA Site: The last large uranium mill tailings pile to be cleaned up in the United States

The U.S. Department of Energy (DOE) is tasked with cleaning up surface contamination and developing and implementing a ground water compliance strategy to address contamination resulting from historical uranium-ore processing at the Moab, Utah, remedial action site. During the years of operations, the facility accumulated approximately 10.5 million tons of tailings and contaminated soils in an unlined pile about 750 feet from the Colorado River. The DOE preferred alternatives are to relocate the tailings to an alternate site away from the river and to implement long-term ground water remediation. An interim action ground water extraction/injection system is currently in operation to reduce the contaminant mass in ground water discharging to the river.

Kenneth E. Karp, Donald R. Metzler
U isotopic fractionation — a process characterising groundwater systems

The activity of

234

U relative to

238

U (AR) in groundwaters is controlled by isotope fractionation in water-rock interface. The fractionation is controlled by redox-conditions and rock-groundwater contact time. The measured ARs form thus an important source of information and offer an effective tool to characterise groundwater systems along with other hydrochemical data. The purpose of this paper is to elucidate the link between ARs and groundwater conditions. The paper considers the formation of AR in groundwaters and examines measured data from several study sites in the Fennoscandian Shield.

Juhani Suksi, Kari Rasilainen, Nuria Marcos
Contamination of Hydrographic Bassins in Uranium Mining Areas of Portugal

The uranium-radium mining industry generated about six million tons of radioactive by-products composed mainly by the tailings of uranium milling facilities and by fine mud deposits resulting from treatment of acid mine waters. Most of these radioactive materials are deposited on the ground in the village of Urgeiriça, near Viseu, and are currently exposed to weathering. Following rains, leaching and surface runoff of these tailings drain into a stream, Ribeira da Pantanha that joins the river Mondego. In this river a wide artificial lake, Barragem da Aguieira, is the main water reservoir for the centre region of the country. Other rivers flowing through the mining region, namely the rivers Dão, Vouga and Távora, may also receive drainage from the areas of old uranium mines. The radioactive contamination that uranium mining and milling wastes may have originated in rivers and water reservoirs is assessed.

Fernando P. Carvalho, João M. Oliveira, Maria J. Madruga, Irene Lopes, Albertina Libânio, Lubélia Machado
Environmental impact evaluation of uranifer waste dumps from mining explorations — Barzava mine

The Barzava Uranium Mine is located in the west of Romania, in Arad District, in the south of the Zarand Mountains. The exploitation of the Uranium Ore started in 1963. This procedure was achieved by 2 shafts and 2 galleries located in the Poc Stream Valley, an affluent of the Barzava River. In 40 years, the waste rocks suffered erosion and migration activities of the Uranium. It contaminated the soil nearby. The waste rock from the Central Shaft 3 is located in the Barzava City, extremely close to the Barzava River and lengths on a 3,600 sqm surface. It has a 20,000 m

3

volume and the gamma debit values are within 0, 3 µSv/h and 4.5 µSv/h as maximum values and the Radon have a concentration of 1,250 Bq/ m

3

.

Dragos Curelea, Dan Georgescu, Florian Aurelian, Camelia Popescu
Hydrochemical Aspects of the Flooding of the Mine Königstein — A Water Mixing Model for Recognizing the Influence of Groundwater by Contaminated Water

A water mixing model has been developed which supports the decision for evaluating the influence of groundwater by contaminated water. Given the main statistical parameters of the water classes (mean and standard deviation), for each concrete value vector a probable water mixture is determined. If the value vector is close to the probable water mixture, an influence by the contaminated water can be assumed. The model has been implemented in a software program and tested on the basis of the flooding data of the mine Königstein.

Karl-Otto Zeißler, Kerstin Nindel, Thomas Hertwig
The use of BaSO4 supersaturated solutions for in-situ immobilization of heavy metals in the abandoned Wismut GmbH uranium mine at Königstein

The former uranium ISL-mine at Königstein (Germany) is presently being flooded. To support the flooding process, a new technology to reduce contaminant potential in the source was developed and applied. The application based on the injection of supersaturated BaSO4-solutions to precipitate solved contaminants and to cover reactive mineral surfaces. Since 2002 the technology is applied in the southern part of the mine in order to immobilize contaminants in highly polluted areas before flooding. The article describes the fundamentals of the technology and the full-scale application.

Ulf Jenk, Udo Zimmermann, Gerald Ziegenbalg
Management of uranium mill tailings and associated environmental monitoring in India

Mining of low grade uranium ore commenced at Jaduguda in eastern India in the mid 1960s. Presently, the uranium ore from four underground mines located within a distance of 22 km is processed by the Uranium Corporation of India Ltd. (UCIL). A few more mines are envisaged to meet the nuclear fuel requirements. Management of mine water, mill tailings and the effluents from the tailings containment facility is given due importance. Liquid effluents are treated with BaCl2 and lime slurry to remove 226Ra, Mn and other pollutants. A large portion of the treated effluents is re-used, the rest being disposed to the aquatic system after ensuring that they meet the regulatory standards of discharge. Surface and ground water monitoring results are presented in the paper.

Amir Hasan Khan, V.N. Jha, R. Kumar, S.K. Sahoo, A.K. Shukla, R.M. Tripathi, V. D. Puranik
Cover and final landform design for the B-zone waste rock pile at Rabbit Lake Mine

A detailed study was undertaken to evaluate various cover system and final landform designs for the B-zone waste rock pile at Rabbit Lake Mine in Canada. Several tasks were completed including physical and hydraulic characterization of the waste and potential cover materials and numerical modelling to examine erosion and slope stability. Soil-atmosphere numeric simulations were conducted to predict net infiltration and oxygen ingress rates through several cover system alternatives. A seepage numerical modelling programme was completed to predict current and future seepage rates from the base of the pile for alternate cover system designs. Several final landform alternatives were developed for the pile along with a preliminary design for a surface water management system. The potential impact of various physical, chemical, and biological processes on the sustainable performance of the final landform was also considered. This paper provides an overview of the investigations completed towards the development of a cover system and final landform design for the B-zone waste rock pile.

Brian Ayres, Pat Landine, Les Adrian, Dave Christensen, Mike O’Kane1
A GPS-Based System for Radium/Uranium Contamination Gamma Scanning

MFG Inc. in 2001 developed a Global Positioning System (GPS)-based gamma scanning technique for use during site surveys at a large (16 km2) in-situleach uranium mine being developed in Kazakhstan. Since that time, the system has been improved and used at a total of eight radium/uranium-contaminated sites in the western U.S. At one former uranium mill site in Texas, data acquisition occurred at a rate of seven acres/hour on the 600 acre site. High-speed scanning allows 100% coverage of a site in a short period, providing color-coded output defining gamma exposure rates over the entire site.

Robert Meyer, Michael Shields, Scott Green, Janet Johnson
Use of underground excavated space for disposal of low radioactive mining waste resulted from uranium ore exploitation. Study case

The article presents the actual situation of the Avram Iancu uranium mine, located in Romania; where important quantities of radioactive waste rock from the uranium mining industry accumulated and become a major risk for the environment. The result of the analysis of the particular conditions of this mining perimeter was that the relocation of the contaminated material in the abandoned mines pits is the most advantageous solution regarding the long term protection against radiation and the costs.

Dan Bujor Nica, Dan Georgescu, Traian Boboiceanu, Stefan Petrescu
Changes in discharged water quality from abandoned uranium mines near Kalna

Various genetic types of uranium minerals (infiltrated, hydrothermal, etc.) have been found in the region of Stara Planina. Uranium minerals in granitic rocks that build up the area of Kalna in central Stara Planina are selected for their importance and the degree of exploration. The analyzed levels of the natural radioactive and trace elements in water and fluvial deposits from a general area of the closed mines are presented in this paper. Relatively wide ranges of the obtained uranium concentrations in ground and surface waters are explained in this work by the presence of various geochemical barriers and by the variations in the quantity and velocity of ground water flow over the year.

Zoran Nikić, Jovan Kovačević, Branislav Radošević
Environmental impact evaluation of a pilot installation for “in situ” processing for uranium ore

As a result of the Gamma Geological Research during the 1955–1956 period in the south-west of Romania, there were identified some radioactive anomalies organized in 16 areas. These are placed near Danube River and some of its confluent rivers (Streneac, Ilişova). The exploitation of the Ilisova Uranium Ore started in 1962 and it was partially suspended in 1972. The exploration and exploitation activities restarted in 1976. In the same time it was also started the pilot project consisting in the acid leaching “in situ” of the Uranium Ore extracted from the Ilişova Mines. After 1990 the activity was stopped and all activity abandoned. In 2002, the closing and rehabilitation procedures of the perimeter affected by the exploitation and exploration of the Uranium Ore was started, especially because this perimeter is in the National Park “Portile de Fier” land.

Stefan Petrescu, Dan Georgescu, Simona Ciuciu, Dragos Curelea
Concept of a Surface Water Monitoring at the Former Uranium Mining Site Schlema-Alberoda

After the remediation works at the Schlema-Alberoda Mining Site the existing water monitoring has to be modified. The monitoring has to focus on the main contaminated streams. The separation of contaminated and not contaminated streams an their distribution in surface respectively underground portions allows the determination of the real transported load of radioactive and toxic compounds. The principle of load determination is the more suitable concept in the assessment of discharges like in industry and waste water treatment (EU).

Petra Schneider, Ralf Löser, Jürgen Meyer, Elke Kreyßig, Andrea Schramm
Potential environmental impact resulting from inadequate remediation of uranium mining in the Karoo Uranium Province, South Africa

Inadequate remediation of uranium mining in the Karoo Uranium Province, South Africa led to a disused open pit and inclined shaft, uranium ore in stockpiles and barrels, as well as other mining related equipment.

Land owners were unaware of the potential threat of uranium and coherent heavy metals resulting in livestock grazing amongst ore stockpiles and drinking from contaminated water supplies. Land owners consequently used stockpiled uranium ore for gravel road maintenance and construction of farmhouse foundations. The concentration of the radioactive gas radon (

222

Rn) was monitored in the aforementioned farmhouse and reached 835 Bq.m

−3

, thus exceeding the concentration limitations (150 Bq.m

−3

) for radon gas in dwellings set by the United States Environmental Protection Agency.

Lycium cinereum, Fingerhuthia africana, Aristida congesta congesta

and

Phragmites australis

growing within these mining locations revealed high concentrations of uranium and molybdenum in leaves and roots.

Lycium cinereum

were found to accumulate molybdenum up to 650 ppm in some leaves. Uranium readily accumulates in the roots of some of the species, whilst only a fraction is translocated to the leaves. Plants were also subjected to protein profile studies revealing a general tendency that with an increase in uranium and molybdenum concentrations, protein concentrations in the leaves tend to decrease. These fauna serve not only as a toxicological hazard for grazing livestock, but also as potential phytoremediators of polluted soils.

Xenopus laevis

were found to reside within a water filled open pit where uranium and molybdenum concentrations reach 20 mg/l and 4 mg/l respectively. These aquatic organisms contain high hepatic, renal and bone concentrations of uranium and molybdenum. Histological sections of liver and kidney revealed anomalous levels of lymphocytes, indicative of infection or neoplasia, possibly as a result of heavy metal uptake.

Nico Scholtz, O.F. Scholtz, Gerhard P. Potgieter
Regulating Idle Uranium Mines In Canada

On May 31, 2000 the

Nuclear Safety and Control Act (NSCA)

came into force in Canada. As a result of changes introduced in this new legislation new attention was brought to the assessment and regulation of these legacy properties. Most were abandoned and their safety and long-term management is the responsibility of various levels of government. Canadian Nuclear Safety Commission (CNSC) staff initiated the Contaminated Lands Evaluation and Assessment Network (CLEAN) program to determine what regulatory activities were required at these and other sites in Canada. The idle mine portion of the CLEAN program began as an outreach program to inform various stakeholders of their responsibilities under the

NSCA

and to catalog the available information for each of these mines. This resulted in two separate initiatives, one to licence high-risk sites and one to exempt radiologically low-risk sites from CNSC licensing.

Ron Stenson
Long-term Impacts of Gold and Uranium Mining on Water Quality in Dolomitic Regions — examples from the Wonderfonteinspruit catchment in South Africa

A number of gold and uranium mines in South Africa are located in areas where compartmentalised dolomitic rock forms extensive karst aquifers over-laying mined reefs. Apart from dewatering of such aquifers triggering widespread sinkhole formation and impacting on water availability by drying up of springs and boreholes, mining activities also impact on the quality of local water resources. Of particular concern to downstream users is uranium pollution of ground- and surface water often associated with gold in the mined reefs. This paper estimates potential U-fluxes associated with different types of mining-sources assessing their varying significance in past, present and future.

Frank Winde
Tracer Tests as a Mean of Remediation Procedures in Mines

Mining usually causes severe anthropogenic changes by which the ground- or surface water might be significantly polluted. One of the main problems in the mining industry are acid mine drainage, the drainage of heavy metals, and the prediction of mine water rebound after mine closure. Consequently, the knowledge about the hydraulic behaviour of the mine water within a flooded mine might significantly reduce the costs of mine closure and remediation. In the literature, the difficulties in evaluating the hydrodynamics of flooded mines are well described, although only few tracer tests in flooded mines have been published so far. Most tracer tests linked to mine water problems were related to either pollution of the aquifer or radioactive waste disposal and not the mine water itself.

Applying the results of the test provides possibilities for optimising the outcome of the source-path-target methodology and therefore diminishes the costs of remediation strategies. Consequently, prior to planning of remediation strategies or numerical simulations, relatively cheap and reliable results for decision making can be obtained by the use of tracer tests.

Christian Wolkersdorfer
Typification of Radioactive Contamination Conditions in Ground Water at the Semipalatinsk Test Site

For the first time the complex investigations on study of radioactive contamination in ground water at the underground nuclear explosion sites were carried out at the Semipalatinsk Test Site. Definition of the radioactive contamination aureoles of the basic water-bearing horizon located within the exogenous rocks fracturing area is based on the proper analysis of the experimental data on the biologically hazardous radionuclides content. Data on the current radionuclide activity in water-bearing horizon can be used for the retrospective analysis of the radioactive contamination of geological environment.

Ella Gorbunova
Spatial and temporal variations in the uranium series background in Alpine groundwater

In areas with uranium mining it is hard if not impossible to decide if increased uranium, radium or radon levels are due to these industrial activities or if they are just natural variations. There are rarely reliable data available taken prior to mining. Therefore our data from the Swiss Alps, a region with known uranium mineralizations but no uranium mining may help to get an idea about the range of spatial and temporal variations of the natural background. They may also serve as a baseline against which possible influences of climate change or future industrial activities in the Alps can be compared.

Heinz Surbeck, Otmar Deflorin, Olivier Kloos
Distribution Pattern Uranium Isotopes in Lake Sediments

Sediment samples from three Egyptian Lakes’ (Qarun, Bardawill and Edku) were collected to study the environmental behavior of naturally occurring radionuclides in these lakes. The three lakes have different hydro-geological, physical and chemical features, which could affect the concentrations and the distribution pattern of uranium isotopes in the lakes’ sediments. In this study, the specific activity of uranium isotopes (U-238, U-235 and U-234) were measured using alpha spectrometers after radiochemical separation and uranium alpha source electroplating on stainless steel disk. The distribution patter of uranium and the affects of sediment texture, organic matter contents, and other ecological parameters were investigated.

Ashraf Khater
Origin of high 234U/238U ratio in post-permafrost aquifers

Isotope composition and concentration (δ

2

H, δ

18

O,

234

U/

238

U, Ar,

40

Ar/

36

Ar,

3

He/

4

He and

20

Ne/

4

He) were measured in the groundwaters (Tomsk-7). Water has a distinct cold climate isotope signature δ

2

H = −127..−140, δ

18

O = −17.0..−18.2 in contrast of modern meteoric water δ

2

H = −117, δ

18

O = −15.9. Stable isotopes are in concord with noble gas temperature t

NGT

= 0..+4 °C and helium model ages t = 7−14 ka. Disequilibrium uranium

234

U/

238

U up to 16 (activity ratio) obtained and explained of

234

U leaching by the melt water during the permafrost degradation.

Igor Tokarev, A.A. Zubkov, Vyacheslav G. Rumynin, V.A. Polyakov, V.Yu. Kuznetsov, F.E. Maksimov
Uranium in phosphate fertilizer production

The production of fertilizers from natural phosphate ore can lead to the redistribution of uranium and other radionuclides in products, by-products and residues and, hence, to environmental impacts and increased radiation exposures.

Uranium and other radionuclides are mainly found in the process residue phosphogypsum and to a lesser degree in the final fertilizer products. The input of radionuclides of natural origin into the food chain via phosphate fertilizers appears to be of lesser concern. Because the radionuclide activity concentrations in most of the process materials are only slightly above levels in soil, the need for specific measures to control radiological hazards to individuals and the environment is very limited. In most cases, normal occupational health and environmental protection measures designed for non-radiological hazards will be sufficient to protect against radiological hazards as well.

W. Eberhard Falck, Denis Wymer
Uranium contents in acidic lakes and groundwater of Lower Lusatia (Germany)

Acidic pit lakes are typical for the landscape of Lower Lusatia. The lakes of a former lignite mine were investigated to find remediation strategies. Hydrogeology and geochemistry of the drainage basin were characterized by collecting numerous data. This study is focussed on the geochemistry of uranium. The investigated waters have low U concentrations (≤ 2 µg/l). There is no definite correlation between pH and U concentration.

Elke Bozau, Hans-Joachim Stärk
Changes in Uranium concentration in the Weisse Elster River as a mirror of the Remediation in the former WISMUT mining area

Since 1990 the research group “Pollutant Dynamics” at the Saxon Academy has been investigating the process of self-purification of the former highly anthropogenically affected river Weisse Elster. This long term study, focusing on uranium, includes the components water (< 0.45 µm), suspended matter (SPM), sediment and floodplain soil (grain-size < 20µm,) from 1990 up to 2004.

Wolfgang Czegka, Christiane Hanisch, Frank Junge, Lutz Zerling, Martina Baborowski
Factors affecting the plant availability of uranium in soils

Uranium (U) is a toxic heavy metal. The background values of natural soils differ between 0.79–11 mg kg

−1

U. U is accumulated in the A horizons and its plant availability is influenced by both natural soil properties and anthropogenic activities. Recently, the use of phosphorus fertilizers in agriculture will be reported as a longer-term risk for the soil-plant-system. An alien source of environmental pollution results from military operations. Soil fertility, pH value and nutrient supply can effect the U content of crops growing on U contaminated soils.

Susanne Schroetter, Maria Rivas, Maria Lamas, Jürgen Fleckenstein, Ewald Schnug
Backmatter
Metadaten
Titel
Uranium in the Environment
herausgegeben von
Prof. Dr. Broder J. Merkel
Dipl. -Geol. Andrea Hasche-Berger
Copyright-Jahr
2006
Verlag
Springer Berlin Heidelberg
Electronic ISBN
978-3-540-28367-6
Print ISBN
978-3-540-28363-8
DOI
https://doi.org/10.1007/3-540-28367-6