bluuebunny/crossref_metadata_2025 huggingface dataset:
Stabilization of an arid, saline sabkha soil using additives
Authors: Al-Amoudi Omar Saeed Baghabra , Asi Ibrahim Mohammed , EI-Naggar Zaghloul Raghib
Published: November 2007

This paper describes the results of an investigation on the effect of five stabilizing agents, namely limestone dust, marl, emulsified asphalt, cement and lime, on the properties of an arid, saline sabkha soil from eastern Saudi Arabia. Standard compaction and unconfined compressive strength tests were performed, the latter on wrapped specimens that had been allowed to cure for seven days. The results indicated that the density of sabkha mixtures could not be used as a primary criterion in any stabilization programme and the maximum strength of sabkha mixtures was attained at moisture contents much lower than the optimum. Despite the sabkha's coarsegrained nature, neither addition of marl nor of emulsified asphalt gave any significant improvement in the properties of sabkha and the effect of adding limestone dust was marginal. However, the addition of either lime or cement in the range of 2.5 to 100y weight of soil increased the strength between and 22 times.
Chalk fracture system characteristics: implications for flow and solute transport
Authors: Younger P. L. , Elliot T.
Published: November 2007

Bulk groundwater flow and solute advection occur in the fractures of the UK Chalk, and a knowledge of the frequency and aperture of these fractures is crucial to understanding these two key processes in the Chalk. Fracture frequencies in the Chalk of southeast England have been assessed regionally by means of outcrop scanline measurements. Measurements of radon dissolved in Chalk groundwaters allow the estimation of fracture apertures in the saturated zone. These data provide valuable controls on the conceptualization and estimation of hydraulic properties for the Chalk aquifer. In particular, standard hydraulic models of fractured rock permeability applied on the basis of these data are shown to be insufficient to explain the higher permeabilities measured in the unconfined Chalk beneath valley axes. In these settings, conduit flow mechanisms must be invoked; this in turn implies that modifications to standard matrix diffusion models are required to describe solute transport accurately.
Modelling of rising groundwater levels in the Chalk aquifer of the London Basin
Authors: Lucas H. C. , Robinson V. K.
Published: November 2007

The rising groundwater level in the confined chalk aquifer of the Central London Basin syncline has been the subject of study and concern for over a decade. Settlement effects in deep foundations and the flooding of tunnels are seen as the main problems arising from resaturation of the London Clay. The Thames Region of the National Rivers Authority has undertaken to formulate a strategy to monitor and control the rise in groundwater levels. Using a finite element, multi-layer computer model of the London Basin aquifer, various scenarios involving groundwater abstraction have been modelled and analysed up to the year 2040.

The objective of the study has been to optimize the location of potential groundwater abstraction points and the quantities pumped to provide the most effective control of regional groundwater levels. The water available is seen as a valuable resource for public water supply in an area where there is a demand deficit. The economics of utilizing this resource are complicated, however, by variations in water quality, the cost of treatment and the availability of lower cost water from other resources in some areas.
Statistical analysis of water table variations in Bahrain
Authors: Mahmood H. R. , Twigg D. R.
Published: November 2007

This paper reviews and discusses the factors causing the changes of water levels in the aquifers from which Bahrain extracts a large proportion of the water required for human consumption, agriculture and industrial use. These include noteonly geological and climatic features but also the effects of agricultural irrigation, coastal reclamation and leakages from the water supply network, sewer pipes and septic tanks. The results of statistical analyses carried out on water levels obtained from 125 boreholes over a 12-year period, in order to determine any underlying trends in water table movements, are presented and discussed. These analyses have shown that, in general, levels in the deeper aquifers are falling at rates ranging from 78 mm to 277 mm per annum. Variations in the near-surface aquifer are shown to be more complex but with the water table rising under areas associated with land reclaimed from the sea. If levels continue to rise at their present rate, the water table is predicted to be at or very close to the surface by the end of the century. This could lead to various geotechnical, structural, agricultural or health problems.
Hydrocarbon pollution control and remediation of groundwater: a brief review
Authors: Clark L.
Published: November 2007

Pollution of groundwater by petroleum products is widespread in the industrialized nations. Such pollution is likely to be found wherever petroleum products have been stored, used or refined. The scale of a pollution incident can, therefore, range from relatively minor beneath an oil storage tank to major beneath a refinery. The remediation of oil pollution is a large industry actively pursued by environmental agencies, oil users and the oil industry itself. There is a voluminous literature concerning such remediation, including manuals of remediation practice and environmental consultants' brochures. Unfortunately there is a paucity of published case histories of remediation programmes to show the effectiveness of various remediation practices. The remediation of pollution from a fuel spill at Heathrow is discussed and this, together with experience from other sites, is used to examine the cause and effect of such pollution incidents. The effect of the oil pollution, and the difficulty of remediation, vary with the location of the incident and the hydrogeological situation. The difficulty of remediation, for example, will increase with depth of the water table and with the proximity of urban areas. The possible strategies of remediation under various scenarios are discussed on the basis of experience in the investigation and remediation of oil pollution.
The hydrogeology of the Enfield-Haringey artificial recharge scheme, north London
Authors: O'Shea M. J. , Baxter K. M. , Charalambous A. N.
Published: November 2007

The Enfield-Haringey artificial recharge scheme comprises 23 abstraction/recharge boreholes located between Enfield and Haringey in north London. It is a strategic groundwater development aimed at increasing drought yields to meet the 'target level of service' defined by OFWAT for availability of water resources. The hydrogeology of the scheme, revealed by the drilling and testing of 15 new production boreholes is described and its strategic use summarized. The hydrochemistry of the groundwater in the Chalk and Basal Sands aquifer is briefly considered and the likely effects of re-saturation after recharge on the quality of the pumped groundwater is commented on.

This and previous studies have led to a better understanding of the aquifer system and the hydraulic relationship between the Basal Sands and the underlying Chalk. Intensive exploitation in the past led to some dewatering but reduction in abstraction since the 1950s has allowed water levels to recover, a process that is continuing. In most of the Enfield-Haringey area the aquifer is still only partially saturated, hence the potential for artificial recharge. The Chalk aquifer has been found to be typically anisotropic and heterogeneous with the upper 30–40 m being productive. Acidization was found to produce significant increases in well yields. Chalk groundwaters are mainly of a calcium bicarbonate type while those of the overlying Basal Sands are dominated by sulphate. Both groundwaters become progressively richer in sodium at the expense of calcium from north to south, in the direction of groundwater flow and towards more deeply confining conditions.
An empirical liquid permeability—gas permeability correlation for use in aquifer properties studies
Authors: Bloomfield J. P. , Williams A. T.
Published: November 2007

Laboratory permeability studies can contribute significantly to the quantification of aquifer heterogeneity. However, intrinsic permeabilities obtained by standard core analysis techniques using gas are different from those obtained using water. This is because gas measurements may be affected by a molecular phenomenon known as gas slippage. An empirical correlation is presented for liquid and gas permeability measurements obtained for a suite of Permo-Triassic sandstones and shales from the Sherwood Sandstone Group of northern England. Liquid permeability tests were performed using synthetic formation brines and deionized water. Gas permeability tests used nitrogen as the permeant. Liquid permeabilites,
k
l
, ranged from 9.0 x 10
-19
m
2
to 2.4 x 10
-12
m
2
and gas permeabilites, k
g
, ranged from 1.7 x 10
-17
m
2
to 2.6 x 10
-12
m
2
.The liquid and gas permeability data exhibit log-normal frequency distributions; the log transformed liquid and gas permeability data have means of 5.1 x 10
-16
m
2
and 4.3 x 10
-15
m
2
respectively. A linear least-squares fit to the data has the form log
10
k
l
= 1.17log
10
k
g
+ 1.51.
k
l
/
k
g
ratios, in the range 0.03 to 0.9, indicate that Hagen-Poiseuille type models may not provide appropriate descriptions of gas flow in the Sherwood Sandstone.
Permeability impairment around boreholes in micaceous aquiferes
Authors: Blackwell I. M. , Howsam P. , Walker M. J.
Published: November 2007

A number of possible mechanisms, both physical and chemical, are postulated as being potentially damaging to borehole performance in micaceous aquifers. Laboratory studies have been undertaken to assessthe degree to whichthese mechanisms are operative, and the extent of permeability damage which occurs as a result. Some of the processes studied are unique to micaceous formations, while others are enhanced where mica is present. Two key processes identified by the study are: (i)mineralogical and structural alteration of mica particles as a result of increased groundwater salinity; and (ii) mixing of formation sands, either between layers, or with gravel pack material. The studies together with field evidence show that both of these processes can cause a significant reduction in permeability in the vicinity of a borehole, leading to a deterioration in borehole performance. The degree of deterioration which can result from each of the processes is assessed, and recommendations for operation, maintenance and rehabilitation, to minimize damage are made.
Structural damage associated with land subsidence caused by deep well pumping in Bangkok, Thailand
Authors: Eddleston M.
Published: November 2007

Bangkok, the capital city of Thailand, has experienced rapid growth over the last two decades and is relatively prosperous by Asian standards. The city is situated in the lower half of the flat deltaic plain of the River Chao Phraya and lies at ground elevations of between 0.5 and 1.5m above mean sea level, although some areas are even lower and lie below mean sea level. Drainage of the area is poor and takes place by way a network of sluggishly flowing waterways known as ‘klongs’.

A recent report by the Asian Institute of Technology (A. S. Balasubramaniam
et al.
1992)indicated that subsidence phenomena were beginning to be experienced in the city in the early 1960s when rapid population growth resulted in excessive deep well pumping to satisfy the increased demand for water. At present there are approximately 15000 tube wells drilled through the upper 200 m of superficial deposits, with approximately 600 new abstraction licences granted in 1993.

The area in and around the city is underlain by recent marine clay (known as Bangkok Clay) which overlies older deposits of Pleistocene age. These older deposits, which comprise an upper stratum of stiff clay overlying alternating clays, sands and beds of gravel, are of significant thickness. The total depth of superficial deposits overlying the basement rocks in the Bangkok area varies between 500 and 2000m (Anon 1981).

The upper sequence of very soft to soft Bangkok Clay and the underlying stiff clay stratum is consistent over much of Bangkok and
Mineralogy, fabric properties and classification of weathered granites in Hong Kong
Authors: Irfan T. Y.
Published: November 2007

Deeply weathered granitic rocks are encountered in many engineering works in Hong Kong. To date, the engineering properties and behaviour of these granites, and the soils formed from them, have been poorly related to their basic mineralogical and fabric characteristics. In this paper, a model for weathering of granites is established and, based on this, modifications are proposed to the material and mass weathering schemes commonly adopted in Hung Kong for the characterization of weathered granite in engineering uses. A number of chemical indices have been found to be good indicators of chemical weathering whereas the micro-petrographic indices can be used to characterize most fabric elements of weathered granites. Care in the testing and interpretation of test results is required for soils of granitic origin because of specific mineralogy and fabric that is developed.
A comprehensive method of rock mass characterization for indicating natural slope instability
Authors: Mazzoccola D. F. , Hudson J. A.
Published: November 2007

The purpose of this paper is to present an application of the Rock Engineering Systems (RES) methodology for developing a new rock mass classification, sensitive to large-scale instability in natural slopes and suitable for indicating critical sites. In the area under study, located in the Italian Central Alps, and in most natural slopes, analysis is complicated by lack of data, geological complexity, scale of the instability phenomena and the high number of interacting factors. In order to be able to have a structured approach to such complexity, a comprehensive method based on the RES approach was adopted. This is an objective-based approach which allows the utilization of all the information related to the project, tailoring the classification to the actual circumstances. Hence those parameters which are particularly active at the site can be evaluated and the importance of their interactions established.

Following this approach, 19 parameters relating to the general environment and to the rock mass characteristics are considered. Their reciprocal causes and effects are analysed in order to weight each parameter according to its degree of interactivity in the system. The final definition of the rock mass instability index takes into account the variability of the parameter values for different slopes in assigning ratings to different classes of parameter values. In parallel, a predictability rating is computed, according to the presence in the field of a number of ‘indicators of instability’. Both indices allow discrimination of critical slopes, and are in good agreement with field evidence demonstrating the value of the approach.
Progressive weathering and degradation of mudstone in a coastal landslide
Authors: Hodgson R. L. P. , Grainger P. , Kalaugher P. G.
Published: November 2007

The relationship between the processes of landsliding of a coastal cliffand the progressive weathering of a Permo-Triassic mudstone is examined. The landslide, on the southern coast of Devon in southwest England, includes rockfalls, mudflows and a large mudslide. A stepped profile is produced by occasional stronger beds within the mudstone, which is also capped by conglomerate. A combination of partially weathered clasts and disaggregated matrix develops in debris fans and mudflows which feed the main mudslide. Weathering, which increases the plasticity index of the degrading mudstone, is found to be crucial to the general profile being maintained. If the plasticity index becomes too high, mudflows are inhibited because too much water is required, while too low a plasticity index results in material which is reluctant to flow on the slopes beneath the main cliff.
The determination of rock material properties to predict the performance of machine excavation in tunnels
Authors: Arthur C. D.
Published: November 2007

The assessment of rock material properties is a critical element in any site investigation for the planning and construction of a tunnel through rock strata. This is irrespective of the number of rock strata involved and crucial to the determination of ground reference conditions as detailed in CIRIA Report No. 79 (1978).

An extensive suite of laboratory tests is combined with a comprehensive literature search in order to investigate the interrelationships between some commonly cited rock parameters. The suite includes Shore Scleroscope Rebound Values and results from a modified form of the Cerchar Abrasivity Test. In addition, the benefits from mineralogical analyses of rock samples are considered.

Rock material strength and hardness, with regard to common tunnel excavation techniques is found to be a combination of shear and tensile strength and can respectively be designated as cutting strength and abrasivity. An overall classification system is proposed which incorporates these parameters into an unambiguous notation in order to clarify test data and facilitate interpretation. By an appraisal of each testing technique in respect of relative costs and applicability to rock failure under machine excavation forces an incremental approach for rock testing programme is constructed in the form of a flow chart. The model proposes how the efficiency of current test programmes can be improved thus enabling more confident predictions of material properties in single or multi-strata ground along a proposed tunnel route.
Discussion on ‘Chalk fracture system characteristics: implications for flow and solute transport’
Authors: Younger P. L. , Elliot T.
Published: November 2007

M. PRICE writes: Younger & Elliot (1995) used a radon diffusion model to derive apertures and field measurements to determine spacings for fissures (discontinuities through which flow takes place) in the Chalk. Their paper confirmed much existing knowledge, but when they attempted to use their data to calculate hydraulic conductivity values for chalk, they made a fundamental error that invalidated the main conclusions.

Although there are various assumptions, the average estimates of 0.45mm for the apertures and 9.4/m for the frequencies of fissures are in line with expectations. Applying these results to linear laminar flow in three orthogonal sets of smooth, plane, parallel-plate fissures gives a theoretical fissure porosity of 1.35 per cent and, for pure water at around 10°C, a hydraulic conductivity of 98 m/day. The porosity value is similar to the specific yield of much of the Chalk, but this hydraulic conductivity is much higher than is seen for the bulk of the Chalk in the absence of secondary (solutionenlarged) fissures (Price 1987).

However, in the paper, Younger & Elliot derived a value of hydraulic conductivity of 0.001 m/day. They therefore concluded that these fissure apertures and spacings could not explain the hydraulic conductivity of the Chalk even in interfluve areas (p. $46), and that much larger flow conduits must be present to explain the observed hydraulic conductivity values for Chalk beneath valleys. This difficulty is attributable to a simple error; their equation (11) yields results in m/see, not m/day as stated, so the calculated hydraulic conductivity values.
Plenmeller opencast coal site: a geotechnical and planning case study
Authors: Hughes D. B. , Norbury D. R.
Published: November 2007

Plenmeller is a remote upland opencast site in Northumberland designed to produce just over 2 million tonnes of coal during eight years of production. The complex ground conditions comprise thick peat and glacial deposits, overlying much faulted and steeply dipping Coal Measures strata. Previous under- ground workings, high groundwater levels and associated sub- surface reservoirs of water are also present. In order to mine and export the coal off-site, extensive infrastructure works were necessary including impounding embankments for lagoons, public road diversions, an overland conveyor with a tunnel and major river crossing, coal screening and crushing plant and a rapid loading bunker with associated railway sidings.

A lengthy planning history included a public inquiry and a high court heating before coal production commenced in August 1991. Imposed planning constraints required modifica- tions to the development, additional construction works and restoration measures. The combination of the site location, infrastructure requirements and planning constraints gave rise to the need for a wide range of ancillary civil engineering works; this was one of the most extensive programmes in connection with an opencast project in the UK. These engineering works in turn required a substantial geotechnical input. This paper presents a general account of the extensive ground investiga- tions and construction works carried out at Plenmeller, and briefly discusses some geotechnical aspects of the site operations and the construction works.
Troglodyte dwellings of the Loire Valley, France
Authors: Forster A. , Forster S. C.
Published: November 2007

The Loire region of France (Fig. 1) is famous for its many chateaux which represent not only a pinnacle in art and architecture but also are a testimony to the excellence of the local building stone. The Saumur region of the Loire valley has an estimated 1000 km of quarried limestone galleries which were excavated from the 1lth to the 19th century. The stone has been used in buildings ranging from grand chateaux to simple domestic, commercial and agricultural buildings (Bailey 1993) (Fig. 2).

The stone is extracted from thickly bedded, fine-grained Cretaceous limestones of Turonian age, mainly the Tuffeux Jaune of the Upper Turonian or the Craie Micacée of the Middle Turonian (Alcaydé et al. 1976). It owes its wide usage to the fact that it has ideal engineering properties for a dimension stone since it is stronger and more resistant to weathering than ordinary Cretaceous Chalk but not so strong as to be difficult to quarry or carve into decorative features. The stone occurs in deposits with widely to very widely spaced bedding and joint discontinuities which enable it to have been mined in a manner similar to that of the Jurassic, Bath Stone of England.The value of the stone does not lie solely in its architectural or constructional attributes. The abandoned mines remain as very stable underground spaces by virtue of their exceptionally wide bedding and joint spacing. They are relatively dry and, in common with most underground spaces, possess a constant temperature. Thus, they have found
A visco-plastic model for slope analysis applied to a mudslide in Cortina d'Ampezzo, Italy
Authors: Angeli, Maceo-Giovanni , Gasparetto, Paolo , Menotti, Riccardo Massimiliano , Pasuto Alessandro , Silvano Sandro
Published: November 2007

This paper describes a visco-plastic model which, using recorded groundwater levels, is capable of simulating the velocity trend in landslides. It also deals with the phenomenon of shear strength regain that occurs in montmorillonitic clays constituting slopes during periods when landslides are stationary. The model has been validated with long-term observations of a clay slope affected by a mudslide.
Determination of the intact dry density of irregular chalk lumps: a new method
Authors: Lamont-Black J. , Mortimore R. N.
Published: November 2007

A simple, accurate and reliable method of measuring intact dry density (IDD) on small samples of chalk is described. The method proposed employs wax-sealing and water displacement in a eureka pot and is compared with five other methods, including that recommended in the British Standard. The method of laboratory measurement proposed is capable of achieving an accuracy of ±0.025 mg/m
3
, which is necessary in order to distinguish small scale natural density variations. These density variations can also be detected qualitatively with simple techniques, i.e. a geological pick.
Rapid prediction of Building Research Establishment limestone durability class from porosity and saturation
Authors: Moh'd Basem K. , Howarth Richard J. , Bland Christine H.
Published: November 2007

The development of a rapid, non-parametric, and slightly conservative predictor for the estimation of probable weight loss in the standard Building Research Establishment sodium sulphate crystallisation test, and hence of estimated limestone durability class, based on [Porosity
Saturation
]
0.5
is described. The time saving offered by application of the look-up tables provided here reduces the 3–4 weeks required for the Building Research Establishment crystallization weight loss test to a matter of hours and offers considerable practical advantage for rapid assessment of the suitability of limestone building stones quarried abroad (e.g. in Jordan) for use in the salt weathering conditions of the UK. However, there is a relatively large variance associated with this estimator (particularly when the microporosity coefficient exceeds 0.65) and in critical cases it should be followed up by confirmatory use of the standard crystallization weight loss test.
Locally derived earthquake ground motion attenuation relations for Jordan and conterminous areas
Authors: Husein Malkawi Abdallah I. , Fahmi Khalid J.
Published: November 2007

The most recent catalogue of earthquakes in Jordan and conterminous areas is used to derive formulae for the principal seismic ground motion parameters of peak ground acceleration (PGA), surface wave magnitude (M
s
), Mercalli intensity (I
0
(MM)), and epicentral distance (R). In this context, empirical relations characterizing earthquake ground motion attenuation in Jordan are developed. The main purpose of this paper is to assist engineers in estimating ground motion parameters in the pre-planning and design stages of construction as well as to help seismologists in decisions concerning the installation and operation of earthquake strong motion instrumentation around the country.
An integrated study of controls on solute transport in the Lincolnshire limestone
Authors: Lloyd J. W. , Greswell R. , Williams G. M. , Ward R. S. , Mackay R. , Riley M.
Published: November 2007

A study site located in a quarry on the Lincolnshire Limestone has been selected to examine the validity of the ‘dual porosity’ hypothesis and its application in models for the prediction of solute migration. An integrated approach has been adopted for the experimental programme, combining data obtained from both field and laboratory-scale investigations with mathematical modelling. The results of the first to stages of the experimental developments at the site are reported and the results are discussed in relation to he development of a full tracer test programme.

Fracture mapping has been conducted on the face and the floor of the quarry where the vertical fractures are seen to be discontinuous over depth. However, extensive horizontal bedding plane fissures are readily identifiable in the boreholes and represent the main paths for lateral flows. An extensive data collection programme has been conducted to characterize the hydraulic properties of these fissures, as well as the adjacent altered and unaltered matrix. Important results for future tracer testing were obtained from the hydraulic tests which suggest the strong possibility of non-Darcian flow in the fissures under pumping and tracer test conditions and the probability of strong spreading of solutes at injection wells under forced inflows. Preliminary tracer tests confirm the difficulty of employing laboratory defined diffusion coefficients as input data to ‘dual porosity’ models of local-scale transport.
The geology and hydrogeology of Sellafield: an overview
Authors: Chaplow Robert
Published: November 2007

Nirex is responsible for providing and managing a national facility for solid intermediate-level and low-level radioactive waste. Geological and hydrogeological investigations have been in progress at Sellafield in west Cumbria since 1989 aimed at determining whether or not the site is suitable for such a deep repository. Geological investigations have included the drilling of 20 deep boreholes with over 20000 metres of drilling, together with almost 2000 line kilometres of seismic surveys and over 8000 line kilometres of airborne geophysical surveys. Hydrogeological testing and groundwater sampling and testing have provided additional information on the ground conditions at the site.

The results from the investigations show that the Borrowdale Volcanic Group of rocks, the top surface of which is 400–600 m beneath the site at Sellafield, holds good promise as an eventual location for the repository. Further investigations are required before the suitability of the site can be confirmed. These additional investigations will include the construction of an underground rock-characterization facility for which Nirex applied for planning permission to construct in 1994.

The investigations carried out to date have defined the subsurface structure of the area and have defined a stratigraphic subdivision of the Borrowdale Volcanic Group. Groundwater flow within the volcanic rocks has been shown to be occurring through a limited number of fractures and preliminary work has been undertaken to characterize these hydrogeologically significant fractures. Hydrogeochemical studies have begun to characterize the groundwater types and preliminary results have indicated that the groundwaters at depth are saline with residence times in excess of tens of thousands of years.
The geological framework of the Sellafield area and its relationship to hydrogeology
Authors: Michie Uisdean
Published: November 2007

The Sellafield area lies over the transitional zone between the western margin of the Lake District Massif, of Lower Palaeozoic metamorphic and igneous rocks, and the East Irish Sea Basin of younger sedimentary rocks. This paper sets out the general geological framework, and includes aspects such as the structural evolution, sedimentary history, rock properties and fault and fracture characteristics. From this framework, hydrogeological units are identified and linked to hydrogeological parameters as the basis for general hydrogeological models of the Sellafield area. Site specific models of groundwater flow through and around the potential location of an underground repository for radioactive waste are being developed on the basis of detailed characterization of the rock mass. In particular, geological and geophysical methods are applied to improve understanding of groundwater flow and to develop hydrogeological models integrated with the local geological framework.
Hydrogeological testing in the Sellafield area
Authors: Sutton J. S.
Published: November 2007

A summary of the hydrogeological test methodologies employed in the Sellafield geological investigations is provided in order that an objective appraisal of the quality of the data can be formed. A brief presentation of some of these data illustrates the corroborative nature of different test and measurement methodologies and provides a preliminary view of the results obtained.

The programme of hydrogeological testing is an evolving one and methodologies are developing as work proceeds and targets become more clearly defined. As the testing focused on relatively low permeability rocks at depth, the approach to testing differs slightly from conventional hydrogeological well testing and makes extensive use of oilfield technology.
Groundwater chemistry in the Sellafield area: a preliminary interpretation
Authors: Bath, A. H. , McCartney, R. A. , Richards, H. G. , Metcalfe R. , Crawford M. B.
Published: November 2007

Hydrochemical investigations form an important part of the Nirex Site Characterization Programme at Sellafield. They support the development of a conceptual hydrogeological model of the area as it is now, are the main basis for reconstructing the palaeohydrogeological evolution of the area over the recent geological past (which will assist predictions of future evolution) and allow characterization of the baseline hydrochemical conditions in the potential repository rock volume. The deep hydrochemistry of the area of interest is dominated by its location on the margin of the East Irish Sea Basin. To the west of the potential repository zone, the influence of basinal brines has been a feature of the deep sedimentary rocks and the Borrowdale Volcanic Group (BVG) basement for a considerable period of geological time. The brines currently present are inferred to be the result of partial dissolution of Permo-Triassic halite by ancient (probably pre-Pleistocene) meteoric recharge. Within the BVG of the potential repository zone itself, stable isotopic data and estimates of recharge temperature (based on noble gas data) indicate a predominance of old meteoric recharge (probably Pleistocene). These groundwaters are moderately saline and of NaC1 type. Br/CI ratios suggest that a significant component of this salinity is derived from a putative saline groundwater within the Lake District basement further to the east. The BVG within the potential repository zone is overlain by a Permo-Triassic sedimentary sequence containing fresh groundwaters of Ca-HCO
3
type, which are separated from the underlying saline groundwaters by a fairly sharp salinity transition near the base of the sedimentary formations and locally within the topmost part of the BVG.
Conceptual model of the hydrogeology of Sellafield
Authors: Black J. H. , Brightman M. A.
Published: November 2007

Understanding the abundant data from site investigations at Sellafield is considerably aided by having a conceptual model of the groundwater flow system. It also forms the basis for numerical modelling. The idea of conceptual models is explained. In general, a conceptual model identifies the process or processes which cause groundwater movement together with the major limits and boundaries on those processes. The conceptual model for Sellafield is based on processes associated with the Irish Sea Basin competing with the present-day landbased freshwater system. The conceptual model is described in terms of three regimes: the Irish Sea Basin, the Coastal Plain, and the Hills and Basement. The Irish Sea Basin Regime is dominated by basinal processes and contains evaporite-derived brines. The Coastal Plain Regime is a topographically driven system containing freshwater within transmissive sandstones. The Hills and Basement Regime is a transitional regime containing mixed brines and freshwater, driven by gravity near surface and in dynamic equilibrium at depth.

Comparing the conceptual model against measured values of groundwater head and chemistry indicates broad agreement. Closer examination shows the value of understanding and measuring the interfaces between the regimes. Numerical modelling of the system is still at an early stage.
The geology and hydrogeology of the Sellafield area: development of the way forward
Authors: Littleboy Anna
Published: November 2007

This paper summarizes the way in which Nirex has used knowledge of the Sellafield site gained through experience to establish a forward strategic programme of work. The use of iteration between data collection and model refinement in order to ensure the programme remains focused on key uncertainties is discussed. These iterations are described as cycles of site characterization.

A broad framework for site characterization activities is discussed, which identifies the work under three broad headings; potential repository zone (PRZ) studies, regional studies and hydrochemical studies. Work performed under previous cycles of site characterization is summarized and activities planned for the next cycle of site characterization are presented. These are placed in context with the uncertainty which they are designed to address.

The paper concludes by restating the need for the programme of site characterization undertaken by Nirex to be flexible, and to evolve as necessary to ensure new understanding is accommodated, and used to redefine strategy on a regular basis.
A review of the hydrogeological studies for the Cardiff Bay Barrage
Authors: Edwards R. J. G.
Published: November 2007

Plans to construct a barrage across the entrance to Cardiff Bay on the South Wales coast were evolved by the Welsh Office in 1986 in parallel with proposals to establish an Urban Development Corporation to redevelop 1080 hectares of derelict land in South Cardiff. The proposed barrage which is 1.4 kilometres in length will cut the bay off from the adjacent Severn Estuary.

The project was first promoted in 1987 necessitating a Parliamentary Bill to permit its construction in tidal waters. Since the first private Bill was introduced in November 1987 there has been concerted opposition to the proposals, in the main due to the inundation of a winter feeding ground for wading birds (protected SSSI), concerns over water quality and flooding, and fears of a catastrophic rise in groundwater level as a result of the impoundment and the impact of such a rise on the infrastructure of the city.

This paper reviews the work undertaken to assess the impact of the impoundment on the existing groundwater regime as presented to the various Parliamentary Committees and to the public.
Cardiff Bay Barrage: investigating groundwater control in a tidal aquifer
Authors: Heathcote J. A. , Lewis R. T. , Russell D. I. , Soley R. W. N.
Published: November 2007

The Cardiff Bay Barrage Act requires any impact caused by groundwater rise as a consequence of the construction of the Barrage to be remedied. A possible strategy is to control groundwater levels, obviating any rise. Such control would require groundwater abstraction adjacent to rivers which are presently strongly tidal. This strong tidal fluctuation makes difficult the measurement of parameters needed for the design of the scheme.

Two multi-well pumping tests were performed during feasibility investigations. One of these is described, together with two different approaches to interpreting the strongly tidally affected results--a correlation method and a spectral analysis method. Similar results are obtained from both methods, which are compatible with the other results, although both methods are found to have limitations.

The results are then used to constrain analytic and numerical models of the interaction with the rivers, and to assess the feasibility of future groundwater control.
Possible effects of rising groundwater levels on a gasworks site: a case study from Cardiff Bay, UK
Authors: Thomas B. R.
Published: November 2007

The impoundment of the Taft and Ely rivers by Cardiff Bay Barrage will cause a groundwater level rise of varying amounts within South Cardiff, including the Grangetown Gasworks site. Concern regarding the contamination risk to groundwaters and surface water at and in the vicinity of the gasworks site, resulting from a change in groundwater levels due to the barrage impoundment, resulted in the need for further site investigation to provide more precise information for hydrogeological analysis. This paper outlines the site investigation and groundwater studies undertaken, identifies the existing pollution and contamination hazards at the site and evaluates the subsequent risk resulting from an increase in groundwater levels.
Radon investigations for tunnelling projects: a case study from St Helier, Jersey
Authors: Talbot D. K. , Hodkin D. L. , Ball T. K.
Published: November 2007

In St Helier, Jersey, a surface water link and storage cavern are being constructed to alleviate surcharging of the town's sewerage system during periods of high rainfall. Foul sewers will discharge a stormwater/sewage mix into a 25 000 m3 cavern for temporary storage. The cavern will be emptied by pumping to a treatment works at a regulated rate.

As part of the site investigation for the work, an assessment of the levels of radon likely to be encountered during the construction and operation of the cavern was undertaken. Samples of borehole core were analysed in the laboratory to obtain values of radon emanation per unit surface area. These were then combined with design data to estimate radon concentrations in the void.

The method described provides a simple and effective way of assessing radon contamination at the site investigation phase of a project, enabling protection measures to be incorporated into the design at an early stage, so minimizing the exposure of staff to potential harmful levels of radon during both construction and operation.
The public health implications of microbiological contamination of groundwater
Authors: Pedley Stephen , Howard Guy
Published: November 2007

The microbiological contamination of groundwater has profound and severe implications for public health, particularly in small communities and developing countries where groundwater is often the preferred source of drinking water. Although natural groundwater is usually of good quality, this can deteriorate rapidly due to inadequate source protection and poor resource management. Contaminated groundwater can contribute to high morbidity and mortality rates from diarrhoeal diseases and sometimes lead to epidemics. The disposal of excreta using land-based systems is a key issue for groundwater quality and public health protection. The use of inappropriate water supply and sanitation technologies in peri-urban areas leads to severe and long-term public health risks. The use of poorly constructed sewage treatment works and land application of sewage can lead to groundwater contamination close to water supply sources. Microbiological, in particular virus survival in these circumstances is not well understood, but there are indications of extended pathogen survival and therefore increased public health risk.
Gene profiling of skeletal muscle in an amyotrophic lateral sclerosis mouse model
Authors: Gonzalez de Aguilar Jose-Luis , Niederhauser-Wiederkehr Christa , Halter Benoît , De Tapia Marc , Di Scala Franck , Demougin Philippe , Dupuis Luc , Primig Michael , Meininger Vincent , Loeffler Jean-Philippe
Published: November 2007

Muscle atrophy is a major hallmark of amyotrophic lateral sclerosis (ALS), the most frequent adult-onset motor neuron disease. To define the full set of alterations in gene expression in skeletal muscle during the course of the disease, we used the G86R superoxide dismutase-1 transgenic mouse model of ALS and performed high-density oligonucleotide microarrays. We compared these data to those obtained by axotomy-induced denervation. A major set of gene regulations in G86R muscles resembled those of surgically denervated muscles, but many others appeared specific to the ALS condition. The first significant transcriptional changes appeared in a subpopulation of mice before the onset of overt clinical symptoms and motor neuron death. These early changes affected genes involved in detoxification (e.g., ALDH3, metallothionein-2, and thioredoxin-1) and regeneration (e.g., BTG1, RB1, and RUNX1) but also tissue degradation (e.g., C/EBPδ and DDIT4) and cell death (e.g., ankyrin repeat domain-1, CDKN1A, GADD45α, and PEG3). Of particular interest, metallothionein-1 and -2, ATF3, cathepsin-Z, and galectin-3 genes appeared, among others, commonly regulated in both skeletal muscle (our present data) and spinal motor neurons (as previously reported) of paralyzed ALS mice. The importance of these findings is twofold. First, they designate the distal part of the motor unit as a primary site of disease. Second, they identify specific gene regulations to be explored in the search for therapeutic strategies that could alleviate disease before motor neuron death manifests clinically.
Improved Neurological Outcome With Continuous Chest Compressions Compared With 30:2 Compressions-to-Ventilations Cardiopulmonary Resuscitation in a Realistic Swine Model of Out-of-Hospital Cardiac Arrest
Authors: Ewy Gordon A. , Zuercher Mathias , Hilwig Ronald W. , Sanders Arthur B. , Berg Robert A. , Otto Charles W. , Hayes Melinda M. , Kern Karl B.
Published: November 2007

Background—

The 2005 Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care changed the previous ventilations-to-chest-compression algorithm for bystander cardiopulmonary resuscitation (CPR) from 2 ventilations before each 15 chest compressions (2:15 CPR) to 30 chest compressions before 2 ventilations (30:2 CPR). It was acknowledged in the guidelines that the change was based on a consensus rather than clear evidence. This study was designed to compare 24-hour neurologically normal survival between the initial applications of continuous chest compressions without assisted ventilations with 30:2 CPR in a swine model of witnessed out-of-hospital ventricular fibrillation cardiac arrest.

Methods and Results—

Sixty-four animals underwent 12 minutes of ventricular fibrillation before defibrillation attempts. They were divided into 4 groups, each with increasing durations (3, 4, 5, and 6 minutes, respectively) of untreated ventricular fibrillation before the initiation of bystander resuscitation consisting of either continuous chest compression or 30:2 CPR. After the various untreated ventricular durations plus bystander resuscitation durations, all animals were given the first defibrillation attempt 12 minutes after the induction of ventricular fibrillation, followed by the 2005 guideline–recommended advanced cardiac life support. Neurologically normal survival at 24 hours after resuscitation was observed in 23 of 33 (70%) of the animals in the continuous chest compression groups but in only 13 of 31 (42%) of the 30:2 CPR groups (
P
=0.025).

Conclusions—

In a realistic model of out-of-hospital ventricular fibrillation cardiac arrest, initial bystander administration of continuous chest compressions without assisted ventilations resulted in significantly better 24-hour postresuscitation neurologically normal survival than did the initial bystander administration of 2005 guideline–recommended 30:2 CPR.
Atrial Fibrillation Ablation in Patients With Therapeutic International Normalized Ratio
Authors: Wazni Oussama M. , Beheiry Salwa , Fahmy Tamer , Barrett Conor , Hao Steven , Patel Dimpi , Di Biase Luigi , Martin David O. , Kanj Mohamed , Arruda Mauricio , Cummings Jennifer , Schweikert Robert , Saliba Walid , Natale Andrea
Published: November 2007

Background—

The best approach to management of anticoagulation before and after atrial fibrillation ablation is not known.

Methods and Results—

We compared outcomes in consecutive patients undergoing pulmonary vein antrum isolation for persistent atrial fibrillation. Early in our practice, warfarin was stopped 3 days before ablation, and a transesophageal echocardiogram was performed to rule out clot. Enoxaparin, initially 1 mg/kg twice daily (group 1) and then 0.5 mg/kg twice daily (group 2), was used to “bridge” patients after ablation. Subsequently, warfarin was continued to maintain the international normalized ratio between 2 and 3.5 (group 3). Minor bleeding was defined as hematoma that did not require intervention. Major bleeding was defined as either cardiac tamponade, hematoma that required intervention, or bleeding that required blood transfusion. Pulmonary vein ablation was performed in 355 patients (group 1=105, group 2=100, and group 3=150). More patients had spontaneous echocardiographic contrast in groups 1 and 2. One patient in group 1 had an ischemic stroke compared with 2 patients in group 2 and no patients in group 3. In group 1, 23 patients had minor bleeding, 9 had major bleeding, and 1 had pericardial effusion but no tamponade. In group 2, 19 patients had minor bleeding, and 2 patients developed symptomatic pericardial effusion with need for pericardiocentesis 1 week after discharge. In group 3, 8 patients developed minor bleeding, and 1 patient developed pericardial effusion with no tamponade.

Conclusions—

Continuation of warfarin throughout pulmonary vein ablation without administration of enoxaparin is safe and efficacious. This strategy can be an alternative to bridging with enoxaparin or heparin in the periprocedural period.