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The lowland floodplains of the Lao People’s Democratic Republic (PDR) experience prolonged dry seasons characterized by pronounced and common water scarcity, with water supplies increasingly offset with groundwater. Groundwater assessment is still at a very rudimentary stage in Laos, making it difficult to ensure that new water supplies are developed successfully and managed sustainably. The goal of this study is to apply a variety of field hydrogeophysical techniques to this problem and in the process help build and strengthen human and institutional capacity with various stakeholder groups from the government, the university, and the community. The study area focuses on a cross section of the Vientiane Plain (VP) in the Lower Mekong Basin in central Lao PDR to identify and characterize the hydrogeology and groundwater quality. The research collaboration has built and strengthened stakeholder capacity by developing and progressing the hydrogeologic field mapping of the VP. It has provided local undergraduate and postgraduate training opportunities using several different near-surface geophysical and hydrogeologic techniques, some previously untested in Lao PDR. At one of the survey sites, the geophysics has indicated the spatial extent of the shallow aquifer and in the process identified an extensive conductive zone, interpreted as more saline groundwater. Any groundwater development within this or similar zones is likely to be unsuitable as sources for drinking and irrigation water. Engagement with the local village authorities has supported local community members and government to expand groundwater development for rural water supplies. Access to groundwater as a reliable, safe, and secure resource provides an opportunity for strengthening the resilience of farmers to changing climatic conditions. Participatory research collaboration of this kind can positively enhance data and build capacity, which is a required precursor for improving knowledge and management of poorly understood groundwater resources.

Identifying and quantifying recharge processes linked to ephemeral surface water features is challenging due to their episodic nature. We use a combination of well-established near-surface geophysical methods to provide evidence of a surface and groundwater connection under a small ephemeral recharge feature in a flat, semi-arid region near Adelaide, Australia. We use a seismic survey to obtain P-wave velocity through travel-time tomography and S-wave velocity through the multichannel analysis of surface waves. The ratios between P-wave and S-wave velocities are used to calculate Poisson's ratio, which allow us to infer the position of the water table. Separate geophysical surveys were used to obtain electrical conductivity measurements from time-domain electromagnetics and water contents from downhole nuclear magnetic resonance. The geophysical observations provide evidence to support a groundwater mound underneath a subtle ephemeral surface water feature. Our results suggest that recharge is localized and that small-scale ephemeral features may play an important role in groundwater recharge. Furthermore, we show that a combined geophysical approach can provide a perspective that helps shape the hydrogeological conceptualization of a semi-arid region.

Study region The study area is located at Kapunda, South Australia with a semi-arid climate and comprises a fractured rock aquifer. Established in 1842, Kapunda was the first mining town in Australia and its open-pit mine was a key economic driver for the whole continent. The mine was closed in 1879 and the remnant low-grade copper was considered sub-economic, hence the mine has been developed into a tourist attraction. With the recent advances in In-Situ Recovery (ISR), the feasibility of recovering the remnant copper is under consideration again. Study focus A field trial involving lixiviant injection and extraction is under development. This study uses a combination of stochastic groundwater modeling and multiple geophysical techniques to investigate (1) the flow paths of injectant and whether it will reach the Light River, and (2) the injectant residence time in the aquifer. New hydrological insights for the region Depending on the effective porosity of the aquifer, the modeling suggests a probability of 1 %–5 % for the injectant to escape the site. There is a large uncertainty in the simulated injectant residence time, ranging from 200 to beyond 1000 days. These analyses are conservative and do not consider the biodegradability of the injectant, which can achieve a 90 % degradation over 28 days. Our modeling shows no evidence that the injectant can reach the Light River within this timeframe.

Identifying and quantifying recharge processes linked to ephemeral surface water features is challenging due to their episodic nature. We use a unique combination of well-established near-surface geophysical methods to provide evidence of a surface and groundwater connection under a small ephemeral recharge feature in a flat, semi-arid region near Adelaide, Australia. We use a seismic survey to obtain P-wave velocity through travel-time tomography and S-wave velocity through the multichannel analysis of surface waves. The ratios between P-wave and S-wave velocities allow us to infer the position of the water table. A separate survey was used to obtain electrical conductivity measurements from time-domain electromagnetics and water contents were acquired by downhole nuclear magnetic resonance. The combined geophysical observations provide evidence to support a groundwater mound underneath a subtle ephemeral feature. Our results suggest that recharge is localized and that small-scale ephemeral features play an important role in groundwater recharge. Furthermore, we show that a combined geophysical approach can provide a unique perspective that helps shape the hydrogeological conceptualization of a semi-arid region.

Food insecurity is a substantial and persistent problem in the United States. This paper explores key challenges experienced by households relying on the Supplemental Nutrition Assistance Program (SNAP) and food pantries. It also identifies strategies used by these households to cope with these challenges. Qualitative and limited quantitative data collected in two states from households using both SNAP and charitable food pantries were used for the analysis. The findings of this study provide a comprehensive picture of the broad range of challenges associated with relying on public and nonprofit nutrition assistance, particularly the prevalence of adverse health and disability affecting households. Approximately 60% of households identified health conditions, with diabetes and cardiovascular disease being the most commonly cited. Households also experienced challenges with employment, living arrangements and household composition, and transportation, among others. This study also provides insight into strategies employed by households to surmount these obstacles. Illuminating the range of personal and family hardships and the coping strategies of vulnerable populations can inform discussion of potential changes in the design and delivery of public and nonprofit food assistance programs to help alleviate stressors in vulnerable households.

Coal seam gas (CSG) has the potential to be a low-carbon transition fuel, but CSG fields may be a source of fugitive emissions of methane (CH4). We use mobile cavity ring-down spectroscopy (CRDS) m...

A methane (CH4) and carbon dioxide (CO2) release experiment was held from April to June 2015 at the Ginninderra Controlled Release Facility in Canberra, Australia. The experiment provided an opportunity to compare different emission quantification techniques against a simulated CH4 and CO2 point source release, where the actual release rates were unknown to the participants. Eight quantification techniques were assessed: three tracer ratio techniques (two mobile); backwards Lagrangian stochastic modelling; forwards Lagrangian stochastic modelling; Lagrangian stochastic (LS) footprint modelling; atmospheric tomography using point and using integrated line sensors. The majority of CH4 estimates were within 20% of the actual CH4 release rate (5.8 g/min), with the tracer ratio technique providing the closest estimate to both the CH4 and CO2 release rates (100 g/min). Once the release rate was known, the majority of revised estimates were within 10% of the actual release rate. The study illustrates the power of measuring the emission rate using multiple simultaneous methods and obtaining an ensemble median or mean. An ensemble approach to estimating the CH4 emission rate proved successful with the ensemble median estimate within 16% for the actual release rate for the blind release experiment and within 2% once the release rate was known. The release also provided an opportunity to assess the effectiveness of stationary and mobile ground and aerial CH4 detection technologies. Sensor detection limits and sampling rates were found to be significant limitations for CH4 and CO2 detection. A hyperspectral imager’s capacity to image the CH4 release from 100 m, and a Boreal CH4 laser sensor’s ability to track moving targets suggest the future possibility to map gas plumes using a single laser and mobile aerial reflector.

Lao PDR is a poorly developed country, with a large rural population which relies heavily on agricultural production. The Vientiane Plain is one of the most important and largest agricultural produ...

The dermatologic manifestations of porphyrias result from localized cutaneous formation of reactive oxygen species. The significance of these inflammatory mediators may extend beyond the skin, as increased oxidative stress may play a role in the systemic manifestations of porphyrias. Polypodium leucotomos is a tropical fern that has demonstrated antioxidant, anti-inflammatory and photoprotective properties. Although it has proven effective in the treatment of various photoaggravated dermatoses, we are unaware of any prior reports citing Polypodium leucotomos as a beneficial treatment option in the setting of porphyria cutanea tarda. We describe a patient with refractory porphyria cutanea tarda, who demonstrated dramatic improvement in cutaneous lesions following the initiation of Polypodium leucotomos extract. Due to its low toxicity and demonstrated direct interference in the production of inflammatory mediators are central to cutaneous manifestations of porphyrias, we propose consideration of Polypodium leucotomos as a potential therapeutic option for patients with porphyria cutanea tarda.

Artesian springs, which form carbonate mounds at the surface, occur in groups along the southwestern edge of the Great Artesian Basin (GAB), in northern South Australia. Their underground structure...

Surface Nuclear Magnetic Resonance (NMR) is a non-invasive geophysical technique providing the ability to image and investigate aquifer properties. In order to produce reliable images and interpretations of subsurface properties accurate modelling of the underlying physics is required. In magnetic environments, where the background magnetic field varies spatially, challenges can arise that lead to difficulty accurately modelling the excitation process and interpreting the signal's time dependence. We demonstrate using field data collected in the Anangu Pitjantjatjara Yankunytjatjara (APY) Lands of South Australia that neglecting the influence of the magnetic environment can significantly alter the final images and interpretation of the subsurface structure and properties.

The ability to accurately and precisely measure dissolved gas concentrations in groundwater is crucial for environmental monitoring purposes. Unfortunately, the collection of dissolved gas samples in groundwater is challenging because of the loss of dissolved gas in the groundwater as a result of inadequate sampling methodologies and the need to avoid exposure of the samples to the atmosphere. In environments where water can contain large amounts of methane and carbon dioxide (e.g., coal basins), there is a high probability of separation between the water and gas phases during sample collection, making it impossible to accurately measure the gas concentrations in a groundwater sample. In this paper, we describe the design and development of a novel downhole sampler that is used to collect dissolved gas samples in groundwater at in situ pressure. The sampler was used to collect samples from 26 bores in a proposed coal seam gas field in regional New South Wales, Australia. Comparison of CH4 concentration data showed that the gas concentrations were higher using our methodology than when using alternate methodologies, especially when CH4 concentrations were >10000 μg L–1. Not surprisingly, results from the new methodology suggest that isotopic fractionation occurs when samples are collected using alternate methodologies.

Ground-penetrating radar (GPR) was used to map the war- rens of southern hairy-nosed wombats (Lasiorhinus latifrons) in South Australia in a variety of soil types. Although farmers of- ten cull wombats to reduce their impact on infrastructure and agriculture, their population dynamics are poorly understood, and all stakeholders agree that better information is required. Warrens were mapped successfully at four locations, providing insight into how soil type and local conditions affect burrow morphology and how these can influence population abundance. The use of GPR has provided the first noninvasive means of mapping wombat warrens and the first opportunity to conduct follow-up research to determine how warrens might change over time in response to changes in population. Introduction — Background Wombats are the largest burrowing mammals in the world, growing to as much as 1 m in length and weighing as much as 35 kg. One species of wombat, the southern hairy-nosed wombat (SHNW), is found predominantly in South Australia, living in large interconnected burrow systems called warrens (Figure 1). Warrens are vital for the wombats' survival in the harsh climate. Wombats are important ecosystem engineers, and their digging helps to break up hard soils and assists with nutrient turnover and water infiltration. Their burrows are used as homes by a variety of other animals. However, wombats' digging behavior often brings them into conflict with farmers and graziers (sheep ranchers) because wombats can undermine infrastructure, dam- age crops and equipment, and pose safety concerns for farm workers. The main method for farmers to manage an overabundance of wombats is culling, which is a very contentious and emotional issue for everyone in the community. Farmers worry about the damage caused by wombats and the associated viability of their land, whereas the general public and conservation groups are concerned that culling will cause wombat populations to de- crease or become locally extinct. The differing stands on this is- sue tend to be based more on anecdote and personal perspectives than on scientific data. Although surveys suggest that 90% of landholders believe that wombat numbers have increased in the past few decades, few actual population estimates of wombats have been done since 1989. This is complicated by their fragmented distribution, with the populations being under different pressures in differ- ent regions. Because of those reasons, everyone concerned agrees that reliable data are needed to enable better-informed manage- ment decisions, and this is where our research comes in. The nocturnal and burrowing nature of wombats and the remoteness of some populations make them notoriously

In the lower Murray-Darling Basin, most groundwater discharges to the floodplain of the River Murray. Most of the groundwater is of high salinity and therefore can transfer significant salt loads into the river. To mitigate saline groundwater intrusion into the river, salt interception schemes (SIS) have been commissioned since the early 1990s. The SIS intercept highsalinity groundwater flow adjacent to the river floodplain and the intercepted water is pumped to distant evaporation basins. The in-river transient electromagnetic (RTEM) geophysics technique can be used to infer saline groundwater discharge areas and to inform SIS locations. RTEM results have also been used, albeit qualitatively, in the monitoring and evaluation of the performance of SIS. A methodology for evaluating SIS performance has been developed based on the area above the cumulative frequency distribution (ACFD) of RTEM riverbed-only resistivities. In addition to RTEM maps and cross-sections, the ACFD characterises a river reach with a single number. Increases in ACFD, from pre- to post-SIS RTEM surveys, indicate the changing groundwater flow regime and the building of freshwater lenses.

Characterization of geological fault networks in sedimentary basins targeted for coal seam gas development typically use deep-penetrating seismic data. Such methods can reveal the presence of numerous fault zones at depths greater than 100 m but not necessarily show if these extend to the surface or provide a significant degree of hydraulic connectivity between deep and shallower geological formations. Our combined multi-tracer and hydrogeophysical study used transient electromagnetic surveys to image the subsurface in a sedimentary coal seam gas basin (Gloucester Basin, NSW, Australia) and indicated that deep faults (greater than 200 m) from seismic analysis may extend to within metres of the ground surface. Analysis of environmental tracers in surface water and groundwater samples near fault traces showed the presence of hotspots of deeper groundwater from the coal seams discharging into the stream network via the alluvial aquifer. The isotopic composition of methane was extremely variable in groundwater (δ13C-CH4 from –81.6 to –29.2‰ V-PDB) and surface water (δ 13C-CH4 from –56.0 to –19.9‰ V-PDB), suggesting several sources of methane being recycled in the connected alluvial aquifer and stream network. A 4He hotspot (1.67 × 10−6 cm3 STP g−1) in the alluvial aquifer close to a fault line showed high methane (463 µg L−1) with a thermogenic signature (δ 13C-CH4 of −62.4‰ and δ2H-CH4 of −174.7‰). The Gloucester Basin, which has experienced multiple episodes of complex restructuring, displays high dilation tendency of fractures close to fault damage zones with fracture orientations parallel to the orientation of maximum horizontal stress. As a result, there is increased permeability for wells close to the fault damage zone and with increasing depth. These findings resulted in a robust hydrogeological conceptual model of a faulted basin, which can be used in a monitoring and modelling framework for improved evaluation of risk associated with unconventional gas developments.

The Aboriginal population of the Anangu Pitjantjatjara Yankunytjatjara (APY) lands in South Australia is dependent on groundwater for nearly all water needs. In that region, placement of wells in productive aquifers of appropriate water quality is challenging because of lack of hydrologic data and variable aquifer properties. It is desirable to have an improved ability to identify and evaluate groundwater resources in this remote region with cost-effective methods that make minimal impact on the environment. A project supported by the Society of Exploration Geophysicists program Geoscientists Without Borders tested a combined geophysical approach with airborne and ground-based data sets to locate a potential aquifer, confirm water content, and estimate the subsurface extent of the water-bearing zone. This hydrogeophysical approach was an effective means for exploration and evaluation of groundwater resources in APY lands generally, and it characterized a specific aquifer as a case study.

SUMMARY Artesian mound springs occur along the south-western edge of the Great Artesian Basin, in northern South Australia, but their underground structure and relationship to faulting is not well understood. We have performed geophysical surveys over three different systems using a range of techniques: early-time TEM, self-potential, and magnetotellurics. The self-potential data contains a local response due to specific spring vents, and also a broader stronger response due to laterally extensive upwelling in the lower part of the Bulldog Shale, at depths of approximately 100 m. Modelling of TEM and magnetotelluric data show that the confining Bulldog Shale, which is generally very conductive, contains resistive areas underneath springs and spring complexes which are believed to be related to spring-related carbonate deposition. Magnetotelluric modelling in particular indicates that anisotropic resistivity in the form of vertical sheets at a depth of 100 to 200 m, can explain the observations more readily than a conductive 2D feature, suggesting that the structures underlying the springs are sets of closely-spaced faults. The orientation of this anisotropy matches the regional NNW/SSE orientation of spring complexes.

All resistivity/induced polarisation (IP) data are contaminated to varying degrees by inductive coupling. Spectral IP (SIP) data sets are usually more affected than conventional IP data sets as data are collected at higher frequencies, where coupling is stronger. For SIP surveys interpretation is based on examination of the phase response over the entire frequency range so it is necessary to use relatively sophisticated methods to remove coupling. Unfortunately, most of the methods described in the literature are complicated to implement, or are not described well enough to be practical. Pelton et al. suggest a method for decoupling based on the commonly used Cole-Cole equation that is relatively simple to implement using a Monte Carlo examination of the solution space. In this approach the Cole-Cole response is separated into two terms, the ground response and the inductive response. For each data spectrum, a random number generator is used to determine a set of test values for each the seven parameters in the extended Cole-Cole equation. The values for each of the seven variables are limited to â??reasonableâ?? levels based on initial testing of the solution space. The randomly generated Cole-Cole parameters are then used to generate magnitude and phase responses at the frequencies used for the survey. These are compared with the field data and the fit is calculated. This is run 1 million times for each data point and the best fit chosen from the complete run. Results from this study are encouraging, but the method requires refinement.

The full solution for the wavenumber equation in electromagnetic (EM) theory is available, but not routinely used when processing ground penetrating radar (GPR), and electromagnetic induction (EMI) data. The wavenumber approach is important as it is used for the development of concepts such as skin depth and phase velocity, as well as being the basis for more complete interpretation of EM data sets. Approximations that make the solution simpler are common, and sufficiently accurate, provided that the underlying assumptions are not grossly violated. With the advent of lower-frequency GPR systems (25 MHz and below) and higher-frequency EMI systems (greater than 100 kHz) such approximations need to be re-examined. This paper reviews the full wavenumber expression and then compares phase velocity and skin depth equations based on approximations with the equations for the same parameter based on the full solution. This comparison allows the conditions under which the assumptions are valid to be refined. In this paper it is shown that for GPR surveys conducted under transition band conditions, the error in phase velocity estimates based on low-loss assumptions may be 40%. Similarly, for EMI surveys the skin depth estimation errors may be more than 30% when the equation based on quasi-static assumptions is used instead of the full solution.

Salinisation of floodplains along the Murray River is a significant environmental and social problem in south-eastern Australia that can be expensive and time-consuming to monitor. The potential of plant biogeochemistry as an environmental monitoring tool, specifically its innovative application to groundwater salinity detection, is explored in this paper. Major and trace element biogeochemical data were compared to data from three geophysical surveys in the study area as well as field observations of the underlying stratigraphy. The result is an understanding of how groundwater chemistry can be characterised by plants, specifically river red gum ( Eucalyptus camaldulensis ) and black box ( Eucalyptus largiflorens ) leaves. From the survey it is evident that E. camaldulensis and E. largiflorens were both successful in expressing high salinity levels in the subsurface. Molybdenum was the most suitable pathfinder element for high salinity groundwater. The study has important implications for interpreting biogeochemical mineral exploration results; anomalous element concentrations need to be interpreted in relation to salinity levels.

Increased interest in the character of sediments at the base of waterways, for the purpose of managing river salinization, has led to the application of several geophysical techniques for collecting information from this zone. These instream methods are based on established ground and airborne electrical and electromagnetic technologies, including towed transient electromagnetic systems, towed direct current resistivity array systems, and frequency-domain helicopter electromagnetic systems. Although these systems are individually successful, a systematic examination of their relative effectiveness for identifying variations in substrate conductivity for a common stretch of a river remains lacking. We have compared results obtained from data collected using three instream geophysical techniques for a common stretch of the Murray River in southeastern Australia. The Murray River is an important water resource for drinking and agricultural purposes. Data from these surveys were acquired tolocate areas of significant saltwater accession to the Murray from a saline regional groundwater system that discharges into it. The three methods indirectly inform on those reaches that most likely contribute to higher salt loads in the river, and they do this through the identification of a conductive substrate (a gaining reach). For a [Formula: see text] stretch of the river, the methods identified similar variations in the conductivity structure of sediment substrate, although differences were observed in the modeled response relating to intrinsic differences between each system, including the sampling interval and resolution. The helicopter electromagnetic (EM) system is capable of acquiring hundreds of kil-ometers of data in a day, under any river flow condition, from near the river surface to depths in excess of [Formula: see text]. The other two techniques require safe river flow conditions for acquisition, with as much as 50 river km of data per day possible. The ground-based methods had enhanced lateral and vertical resolving capabilities relative to the helicopter EM system, but their depth of investigation was less (usually only [Formula: see text]).

Sarcoidosis is a well-described clinical entity with several types of presentation among different organ systems. However, primary musculoskeletal manifestation is a rare and seldom-described manifestation. A retrospective review of patients seen at our institution from 1999 to 2009 was performed to identify patients with such presentation. Eleven patients with musculoskeletal sarcoidosis were identified. Seven patients presented with solitary lesions, while 4 presented with multiple foci of disease. Histologically, all lesions revealed granulomatous inflammation consistent with sarcoidosis. Cultures and gram stain were negative in all patients. One patient was found to have evidence of pulmonary sarcoidosis after diagnosis of musculoskeletal sarcoidosis. Eight patients had primarily soft tissue involvement with visible masses, while 3 patients had primarily osseous involvement with no mass. Pain was reported by 9 of 11 patients. On magnetic resonance imaging, all lesions were dark on T1, bright on T2, and poorly marginated. Magnetic resonance imaging was noted to be more accurate in revealing the pathology than radiographic imaging. Four patients underwent complete excision and 1 received a steroid injection. The remaining patients required no further treatment after diagnosis. Musculoskeletal sarcoidosis is rare and can present as single or multiple lesions. Definitive diagnosis is made by biopsy. The decision to operate should be based on symptoms, issues with cosmesis, impending fractures, growth, and/or involvement of neurovascular structures. Patients should be evaluated for pulmonary involvement.

A number of tools have been developed to help understand the processes of salinisation at work along the Murray River in Southern Australia. Four techniques that have been used to help investigators either directly measure the salt load entering the river, or to image the distribution of conductivities under the river are examined here. They include Run-of-River surveys (ROR), in-stream towed NanoTEM, in-stream towed Resistivity, and Helicopter EM (specifically using the RESOLVE FDHEM system). Each technique has strengths and weaknesses related to its mode of operation and the approach adopted in field data collection. Run-of-River samples the water salinity directly and then attempts to estimate river salt load and source location. It provides a direct measure of the salt entering the river but a) only provides salt load information and b) generally only provides information on a kilometre scale. The other three techniques are all geophysical techniques that do not directly inform the investigator about salt loads in the river, but provide information about conductivity distributions in the sediments under the river, which then may be related to salt loads. Each of the geophysical techniques sample the instream environment at three to 20 metre intervals, and provide information from near the river surface to depths of between 10 and 40 metres below the surface. Data may be displayed as depth sections, or as contoured depth slices prepared to examine different levels beneath the river bottom.

The salinisation of major river systems in Australia, and in other countries, is primarily determined by the upward movement of saline water from regional aquifers into the river. The migration has been accelerated due to irrigation schemes and farming practices that have changed regional hydraulic gradients driving saline-water in aquifers towards the major drainage points in the landscape. In this paper, we describe results from a transient electromagnetic (TEM) system that has been deployed to monitor the influx of saline water through sub-riverbed sediments. The deployment was a floating arrangement of a commercial fast sampling (high resolution) TEM system that is sensitive to shallow (b50 m depth) resistivity variations. The technique has been extensively trialed around the River Murray town of Waikerie in South Australia. An initial series of surveys along a 40 km section of river showed a range of sub-riverbed resistivities between 1 and 20 Vm, with a top layer of about 10–15 Vm closely following the water depth. Regions of high-resistivity in the riverbed sediments correlated well with saline-aquifer borehole pumping locations, indicating a localized drawdown of fresher river water. Low-resistivity anomalies have been interpreted as regions of saline water influx into the river. The technique is now used for routine mapping in Australia, with over 800 km of the Murray surveyed, and has potential application to other major world river systems.

Increasing salinity in the River Murray is well documented and is of concern environmentally, economically and socially. The Murray Darling Basin Commission and the Mallee Catchment Management Authority engaged the authors to collect base-line in-stream NanoTEM data within the River Murray from Lock 1 to Mallee Cliffs (675 km). This is a new application of a high resolution fast sampling Transient Electro-Magnetic (TEM) system, towed behind a boat, taking soundings every seven to ten metres along the river. The observed NanoTEM response was interpreted against the current understanding of the regional hydrogeology and groundwater processes in and around the river. This paper summarises some of the results from this investigation. The observed response correlates strongly with previously mapped major changes in underlying lithostratigraphy along the Murray River, and with gaining and losing reaches of the river. The extensive length of the survey provides an insight into potential interactions between the river, floodplain and groundwater, but does not replace the need for focussed ground-truthing programs to examine specific correlations. This rapid, portable technique should be applicable outside the Murray-Darling Basin as well as at additional locations within the Basin.

As part of an ongoing commitment to the reduction of salt accession to the River Murray in South Australia, the South Australian Department for Water, Land and Biodiversity Conservation (DWLBC) is engaged in a series of investigations to determine the feasibility of the construction of salt interception schemes (SIS). An integrated multi-disciplinary approach has been adopted to develop an understanding of the hydrogeological processes, which is essential for effective scheme design. To assist in identifying areas of salt accession, a river-borne NanoTEM survey was conducted in September 2003. Previous work at the Waikerie SIS highlighted the success of the river-borne Transient Electro-Magnetic (TEM) technique. These systems can provide valuable information and understanding of salt accession to the River Murray. Traditional methods, such as river EC measurements and Run of River (RoR) EC surveys, have revealed that the Loxton and Bookpurnong reaches of the river receive substantial salt loads. These techniques provide limited spatial resolution, whereas the river-borne TEM has exceptional spatial resolution with soundings every 5 to 10 metres. A total of 80 km of data over a 37 km stretch of the River Murray was collected near the townships of Loxton and Bookpurnong. The survey results correlate well with recent RoR data, sediment core ground-truthing and groundwater model flow budget results.

Infective endocarditis caused by Klebsiella species is rare, with most isolates being K. pneumoniae. We report the case of a 24-year-old intravenous drug user with newly diagnosed seminoma who developed K. oxytoca endocarditis. In addition to having K. oxytoca isolated from blood culture, cultures of that species were obtained from a retroperitoneal metastasis found on original presentation.

Successful implementation of a salt interception schemes (SIS) requires monitoring to determine locations where the scheme needs revision. Current monitoring methods involve near-surface water-salinity measurements, which are affected by water-flow displacement. A survey method that can determine the salinity of water contained in the top few metres of alluvial sediments immediately beneath the river would be a more accurate tool for SIS monitoring. A fast sampling Transient EM technique is investigated as a potential tool for imaging the conductivity of the top 5m of sediment, and thus monitoring the Waikerie SIS in South Australia?s Riverland. A towed TEM array was used to collect 9km of data that shows resistive anomalies correlating with SIS production bores. The system has the advantage of being a small, manageable array and the short inversion time allows same-day interpretation.

Australian Water Environments (AWE) has been engaged by the Bookpurnong - Lock 4 Environmental Association (BL4EA) to investigate the interception of saline groundwater along the River Murray downstream of Berri, South Australia (Figure 1). Groundwater discharge contributes approximately 70 tonnes per day of salt to this reach of the river. Salt loads are predicted to rise to more than 200 tonnes per day over the next 30 years. The proposed Environmental Enhancement Scheme (EES) comprises a series of shallow pumping wells constructed primarily on the floodplain to intercept saline groundwater before it reaches the river. Intercepted groundwater will be pumped to the Noora Disposal Basin located some 25 km inland. A detailed understanding of the hydrogeological environment is essential to the design and effective operation of the EES and similar groundwater interception schemes. In March 2001, Zonge Engineering conducted a fast-sampling TEM (time-domain EM) traverse to investigate changes in sub-surface resistivity across the highland area adjacent the River Murray and the floodplain within the riverine trench. The highland is planted with citrus and has been irrigated since the 1960?s. The shallow depth to saline groundwater within the Monoman Formation aquifer has seriously degraded the health of native vegetation health across the floodplain. In May 2002, twelve shallow wells were constructed along a narrow stretch of floodplain located approximately one kilometre downstream of the first traverse. Accurate formation samples were collected and logged. Zonge Engineering conducted a second fast-sampling TEM survey in June 2002 along a line parallel to the trial borefield to investigate the correlation between TEM data and variations in hydrogeology identified during drilling. This paper reports the results of the two land-based geophysical surveys and comments on the utility of fast-sampling TEM as a tool for mapping subsurface hydrogeology across the highland and floodplain at Bookpurnong.

Anomalous conductive responses that could not be related to obvious geological sources were observed in field data from a CSAMT survey in the Cobar area, New South Wales. Repeat measurements over the anomalous stations were made, yielding a substantially different resistivity response. Approximate positioning of the E-field dipole stations due to the presence of thick scrub was believed to be one possible source of error contributing to the differing responses. Subsequent test measurements in which the E-field dipole angle was varied by 10 degrees east and west of the correct direction demonstrated that such an orientation change resulted in resistivity variations of up to 50% from the true value. This is significantly larger than expected from simple theory, which suggests that the results from location errors up to 10 degrees from correct should only be a few percent. This large variation observed in the Cobar area is believed to be due to a strong geo-electrical anisotropy within the steeply dipping and highly cleaved meta-sedimentary rocks of the Cobar Basin. It was concluded that relatively small errors in receiver orientation could have a large effect on the magnitude of the received signal, which can potentially generate `false' anomalies in the derived resistivity pseudosections and inversions. It is possible that such location errors are commonly made when a standard GPS is used to locate stations on a grid. Based on the experience from the Cobar area, accurate station positioning is clearly a pre-requisite for reliable electrical surveys in any geological terrain. This paper presents field examples demonstrating the potential errors, and the results of applying more-accurate positioning techniques. Recommended methods to gauge the magnitude of the potential errors in any survey area are proposed.

Most irrigation channels in Australia are earth lined and leak water to the surrounding terrain. The cost of lost water can be high in economic and environmental costs. The solution is to completely line the canals or replace them with pipes, both expensive options. An alternative is to focus on areas of highest seepage. In this study we trialed a dipole-dipole resistivity array towed behind a dinghy in the canal. The approach followed trials using electromagnetic techniques in previous years that showed conductivity changes below and around the canals in part reflected seepage. We inverted the resistivity results to sections and statistically analysed the data from various depths in the ground by correlating the resistivity against pondage seepage results. Our conclusion was that the resistivity worked best where there was a diffuse seepage from the canal. The greatest effect was around the watertable. Where seepage rates were low there was no correlation with resistivity. The correlations improved with increasing seepage particularly where the inverted sections indicated the seepage rates were uniform along the channel.

New ways of energy production through the use of coal seam gas plays and geothermal hot dry rock and hot sedimentary aquifer systems pose challenges in identifying and monitoring fluid in the subsurface. We propose the use of the magnetotelluric (MT) method to image static and dynamic fluid distributions in the subsurface exhausting the contrast in electrical conductivity between resistive host rock and conductive fluid-filled, porous rock. Base line MT measurements provide reference transfer functions and inverse models to characterise the electrical conductivity distribute on which is linked with bore hole and other geophysical data to obtain knowledge about fluid distribution at depth. The reference models are used to accurately forward model fluid injection or extraction temporally and spatially. This work shows results from fluid injections at a hot dry rock system at Paralana, South Australia, and its applicability to other geothermal and coal seam gas systems.

Until recently, the only selenium containing amino acid which could be used to completely substitute for a wild type amino acid was selenomethionine (SeMet). In the last decade the preparation of SeMet containing proteins has proved to be valuable tools in the determination of three-dimensional structure by multiwavelength anomalous diffraction (MAD) techniques. The potential utility of a selenium containing tryptophan analog, β-seleno[3,2-b]pyrrolyl- l -alanine ([4,5]selenatryptophan), has recently been demonstrated in the literature. This finding shows promise for the bioincorporation of its positional isomer, β-selenolo[2,3-b]pyrrolyl- l -alanine ([6,7]selenatryptophan), thereby adding to the essential arsenal of selenium-containing amino acids for use in the characterization of proteins. The synthesis of [6,7]selenatryptophan by enzymatic biotransformation with tryptophan synthase from selenolo[2,3-b]pyrrole was carried out as well as its characterization by NMR spectroscopy and thin layer chromatography. Selenatryptophyl dihydrofolate reductase ([6,7]SeTrp-DHFR) was then synthesized in vivo, purified, and found to exhibit no perturbations to enzymatic activity.

A fast and informative tool was required for the delineation of stratigraphy and hydrology and for monitoring salinisation effects around the Stockyard Plains Disposal Basin, which is used as a storage lake for salt water pumped from aquifers close to the Murray River near the town of Waikerie, South Australia. Such salinisation effects include the formation of a perched saline water-table close to the disposal basin and consequent threats to local fresh-water lenses. Ground penetrating radar, direct current (DC) resistivity, time-domain EM (TEM) and low induction number frequency-domain EM (FEM) were compared in terms of efficiency and effectiveness at two survey locations near the Stockyard Plains Disposal Basin. Low induction number FEM measurements were fast to implement but suffered from a non-linear response with ground conductivity in high conductivity areas. Radar methods were ineffective due to high signal attenuation in the highly saline environment. Fast time-sampling TEM successfully depicted a perched saline water table related to leakage from the disposal basin, and was found to be the most useful technique for delineation of hydrogeology due to its high vertical resolution. DC resistivity was the slowest technique, but was found useful in imaging a fresh-water lens. Results from this study suggest that TEM and DC resistivity methods are useful tools for both fresh-water detection and hydrogeology monitoring in saline groundwater environments.

Lode horizons north and south of the Broken Hill, New South Wales orebody contain a number of zones rich in sphalerite and poor in galena. One example is Pasminco Mining's new opencut Potosi Mine, which averages 8.5% Zn and 2% Pb with little other sulphide. The mineralisation at the Potosi Mine has been well defined by applied potential and induced polarisation (IP) surveys, but different techniques are required for deeper, downplunge exploration. Drillhole electromagnetics (DHEM) is routinely used but may miss those zones where sphalerite is almost the only sulphide. It was therefore decided to try a series of drillhole magnetometric resistivity (DHMMR) surveys, since this method responds to contrasting, rather than absolute, conductivity. The results were very successful with the known sulphides (and some previously unsuspected zones) responding at downhole depths of more than 600 m. The method has detected mineralisation at distances greater than 150 m from the drillhole and has given clear responses to sulphides where DHEM has failed. The method has less resolving capability than DHEM, although it has proven to be more definitive where sulphide lenses occur both above and below the drillhole. The results also suggest that the magnetic field, which responds to changes in resistivity, has a much larger search radius than the phase angle, which measures the IP effect. DHMMR is expected to play a wider role in the Broken Hill district and elsewhere, in the search for sphalerite-rich orebodies.

Background: Some children have persistent pain and instability following inversion injuries of the ankle. Radiographs may reveal a small osseous fragment distal to the lateral malleolus, suggesting an avulsion injury of the anterior talofibular ligament and/or calcaneofibular ligament. The avulsion injury may involve an os subfibulare, causing ligamentous laxity and chronic pain resulting from nonunion. This situation must be differentiated from an asymptomatic os subfibulare, which is a normal anatomic variant in 1% of children. The purpose of this study was to evaluate the intraoperative findings and long-term outcomes of patients treated operatively for symptomatic avulsion injuries or a symptomatic os subfibulare. Methods: Twenty-three patients presented with chronic ankle pain and instability, tenderness anterior and distal to the lateral malleolus, and imaging studies (magnetic resonance imaging and/or stress radiographs) suspicious for avulsion injury of the anterior talofibular ligament and/or calcaneofibular ligament. After unsuccessful nonoperative treatment, all patients underwent excision of the osseous fragments, anatomic reconstruction of the anterior talofibular ligament with use of drill holes through the lateral malleolus, and a modified Brostrom procedure. Results: The mean age of the patients was 10.4 years (range, eight to thirteen years) at the time of injury and 13.6 years (range, eight to seventeen years) at the time of surgery, representing a mean delay in diagnosis and treatment of 3.2 years. At a mean follow-up of 4.5 years (range, 2.1 to 13.2 years), the mean Foot and Ankle Outcome Score was 91.4 (range, 87 to 98) out of 100, with all but one patient returning to the preinjury recreational level. Only one patient had a long-term complication. Conclusions: In children with chronic pain and instability associated with an os subfibulare, surgical excision of the os subfibulare combined with reconstruction of the anterior talofibular ligament and a modified Brostrom procedure was effective in restoring ankle stability, eliminating pain, and permitting return to the preinjury functional level. Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.