Class dealignment and the neighbourhood effect: Miller revisited

The concept of a neighbourhood effect within British voting patterns has largely been discarded, because no data have been available for testing it at the appropriate spatial scales. To undertake such tests, bespoke neighbourhoods have been created around the home of each respondent to the 1997 British Election Study survey in England and Wales, and small-area census data have been assembled for these to depict the socio-economic characteristics of voters' local contexts. Analyses of voting in these small areas, divided into five equal-sized status areas, provides very strong evidence that members of each social class were much more likely to vote Labour than Conservative in the low-status than in the high-status areas. This is entirely consistent with the concept of the neighbourhood effect, but alternative explanations are feasible. The data provide very strong evidence of micro-geographical variations in voting patterns, for which further research is necessary to identify the processes involved

Comparative performance of rural water supplies during drought

As rural African communities experience more frequent and extreme droughts, it is increasingly important that water supplies are climate resilient. Using a unique temporal dataset we explore rural water supply (n = 5196) performance during the 2015–16 drought in Ethiopia. Mean functionality ranged from 60% for motorised boreholes to 75% for hand-pumped boreholes. Real-time monitoring and responsive operation and maintenance led to rapid increases in functionality of hand-pumped and, to a lesser extent, motorised boreholes. Increased demand was placed on motorised boreholes in lowland areas as springs, hand-dug-wells and open sources failed. Most users travelled >1 h to access motorised boreholes but 30 m) groundwater performed best during the drought. Prioritising access to groundwater via multiple improved sources and a portfolio of technologies, such as hand-pumped and motorised boreholes, supported by responsive and proactive operation and maintenance, increases rural water supply resilience

Predicting seawater intrusion in coastal groundwater boreholes using self-potential data

Many coastal groundwater abstraction wells are under threat from seawater intrusion: this is exacerbated in summer by low water tables and increased abstraction. Existing hydrochemistry or geophysical techniques often fail to predict the timing of intrusion events. We investigate whether the presence and transport of seawater can influence self-potentials (SPs) measured within groundwater boreholes, with the aim of using SP monitoring to provide early warning of saline intrusion. SP data collection: SP data were collected from a coastal groundwater borehole and an inland borehole (> 60 km from the coast) in the Seaford Chalk of southern England. The SP gradient in the inland borehole was approximately 0.05 mV/m, while that in the coastal borehole varied from 0.16-0.26 mV/m throughout the monitoring period. Spectral analysis showed that semi-diurnal fluctuations in the SP gradient were several orders of magnitude higher at the coast than inland, indicating a strong influence from oceanic tides. A characteristic decrease in the gradient, or precursor, was observed in the coastal borehole several days prior to seawater intrusion. Modelling results: Hydrodynamic transport and geoelectric modelling suggest that observed pressure changes (associated with the streaming potential) are insufficient to explain either the magnitude of the coastal SP gradient or the semi-diurnal SP fluctuations. By contrast, a model of the exclusion-diffusion potential closely matches these observations and produces a precursor similar to that observed in the field. Sensitivity analysis suggests that both a sharp saline front and spatial variations in the exclusion efficiency arising from aquifer heterogeneities are necessary to explain the SP gradient observed in the coastal borehole. The presence of the precursor in the model depends also on the presence and depth of fractures near the base of the borehole. Conclusions: Our results indicate that SP monitoring, combined with hydrodynamic transport and geoelectric modelling, holds considerable promise as an early warning device for seawater intrusion. We now aim to refine our understanding of the technique by applying it to a range of aquifer types

Permeability of the crystalline basement in Uganda : evidence from 665 pumping tests and implications for solar pumping

Crystalline basement rocks of Precambrian age underlie nearly three quarters of Uganda, providing groundwater supplies to meet ever increasing demand from rural areas and urban growth centres. Development of groundwater sources is commonly based on several factors including physical and socio-economic considerations that have a bearing on their functionality and long term reliability. Here we present new transmissivity data from 665 boreholes across basement aquifers in Uganda calculated from previously unanalyzed pumping test data. Other data are available to help interpret the transmissvity values, including borehole lithological logs, weathering thickness, well design and depth to groundwater. Spatial and depth comparisons are made to relate aquifer permeability to lithology and weathering, and also to relate borehole yields to well design. The data provide an improved understanding of the physical permeability of weathered crystalline basement rock aquifers across Uganda, complimenting earlier studies of vertical permeability profiles in focused areas. The analysis helps inform the physical capacity of the aquifer to supply the borehole yields to meet increasing demands, and application the potential for higher abstraction technologies, such as solar pumps

Physical factors contributing to rural water supply functionality performance in Uganda

This report communicates the findings generated from one of the project surveys – deconstruction and forensic analysis of 50 individual water points in Uganda. The report presents the new data generated to Uganda’s groundwater resource potential; the nature and condition of hand-pump borehole installations; and the significance of both of these factors to service performance. Based on the evidence collected, the main physical factors affecting functionality performance within Uganda are the poor condition of handpump components, and the complex aquifer resource. The impact of these factors can be mitigated through appropriate material choice for handpump components (non GI), increased investment in borehole siting and testing, and adequate accessibility to repairs and maintenance capacity with breakdowns. These factors should not be considered to be the only driving forces of functionality outcomes in these regions of Uganda, however, and the results of this survey need to be examined alongside the wider project findings. Wider institutional arrangements, resources and dynamics, are likely to play a significant role in the implementation of appropriate borehole construction, siting and design; procurement processes; and the management capacity available for water points at national to local levels

Physical factors contributing to rural water supply functionality performance in Ethiopia

This report communicates the findings generated from one of the project surveys – deconstruction and forensic analysis of 50 individual water points in Ethiopia. The report presents the new data generated to Ethiopia’s groundwater resource potential; the nature and condition of hand-pump borehole installations; and the significance of both of these factors to service performance. Based on the evidence collected, the survey results indicate the main physical factors most likely to affect functionality performance within the Ethiopian Highlands are the relatively deep depth to groundwater and the poor condition of handpump components. The impact of these factors to functionality performance can be mitigated through appropriate pump technology choice (e.g. use of deeper handpump boreholes (HPB) lift design), handpump construction, and adequate accessibility to repairs and maintenance capacity with breakdowns. These factors should not, however, be considered to be the only driving forces of functionality outcomes in these regions of Ethiopia, and the results of this survey need to be examined alongside the wider project findings. Wider institutional arrangements, resources and dynamics, are likely to play a significant role in the implementation of appropriate borehole construction, siting and design; procurement processes; and the management capacity available for water points at national to local levels

Physical factors contributing to rural water supply functionality performance in Malawi

This report communicates the findings generated from one of the project surveys – deconstruction and forensic analysis of 50 individual water points in Malawi. The report presents the new data generated to Malawi’s groundwater resource potential; the nature and condition of hand-pump borehole installations; and the significance of both of these factors to service performance. Based on the evidence collected, the main physical factor affecting functionality performance within Malawi is shown to be the poor condition of handpump components. Functionality of handpumps is considerably higher than in the other study countries, Ethiopia and Uganda, and the resource potential, depth to groundwater and recharge are generally favourable. Improved systems for rapid maintenance and repair would help increase functionality further. This finding should not, however, be considered to be the only driving force of functionality outcomes in these regions of Malawi, and the results of this survey need to be examined alongside the wider project findings. Wider institutional arrangements, resources and dynamics, are likely to play a significant role in the implementation of appropriate borehole construction, siting and design; procurement processes; and the management capacity available for water points at national to local levels

Assessment of occurrence and origin of toxic metals in groundwater sources for domestic use in Enugu, Nigeria : pilot study results

In April of 2021, during routine water quality testing on five handpump borehole sources installed by WaterAid in Ugwuaji, Engugu, Nigeria, lead and cadmium were discovered to be above permissible limits in three of the handpump sources. As a result, WaterAid Nigeria commissioned the British Geological Survey and University of Ibadan to conduct further investigation of the occurrence, concentration and origin of lead in handpump boreholes in the Engugu region. This report describes the findings of a pilot study which focused on identifying the origin and quantifying the concentrations of dissolved and total lead (Pb) and cadmium (Cd) present in boreholes equipped with handpumps. Concentrations of Pb and Cd in handpump boreholes were also compared to concentrations of these elements in other water source types, including shallow hand-dug wells, surface water and boreholes with submersible pumps installed. A total of 32 water samples were collected, including seven shallow hand-dug wells and six surface water samples. Five water samples were also collected from one shallow hand dug well and four handpump boreholes outside Ugwuaji. In addition, a small number handpump component samples were collected (i.e. PV pipe and metal scrapings). Six samples of soil from well cuttings and rocks along the river channels were also collected for Pb isotope analysis to identify potential sources of Pb within groundwater. The samples were sent to three different laboratories (National water resources institute (NWRI) International Institute of Tropical Agriculture (IITA) and British Geological Survey (BGS)) for analysis of major ions and trace metals (focusing on Pb and Cd). The results of the elemental analysis found no consistency in concentrations of either Pb or Cd between laboratories. While some level of variation between results from different laboratories is to be expected, the differences in Pb and Cd concentrations between the laboratories are significant, non-systematic and beyond what might reasonably be expected, raising concerns about the accuracy of results reported from the local labs. Possible sources of uncertainty could be the purity of the acid used, the standards used, and other QA procedures used by the Nigerian labs. The results from the BGS laboratories indicate that concentrations of Pb and Cd are below WHO guideline values and Nigerian permissible limits in most samples. A single unfiltered sample (i.e. total concentration which includes dissolved and particulate Pb) from the BGS analyses had Pb concentration (10.5 μg/L) exceeding the WHO and Nigerian guideline values for drinking water of 10 g/L. Median Pb and Cd samples were highest in samples taken early in the morning before the days pumping had begun (5.01 g/L and 0.036 g/L respectively) suggesting the handpump materials as a possible source of both elements. There was no systematic increase in heavy metal concentrations for Pb and Cd in unfiltered samples compared to filtered samples, suggesting that for most samples analysed these contaminants are in solution. However, further work on paired dissolved and total samples would help quantify the proportion of dissolved and particulate concentrations and indicate the risk of drinking unfiltered water from the handpump boreholes. No samples analysed by BGS had Cd concentrations exceeding the WHO or Nigerian guideline values for drinking water for Cd of 3 μg/L and 5 mg/l respectively. Analysis also showed samples from four sites exceeding the guideline value/national standard for fluoride (1.5 g/L) in drinking water (range 2.39-2.49 g/L). The lead isotope data suggest that the lead found in the water samples analysed (i.e. samples with > 1 μg/l) does not come from the local soil/sediment/cuttings. It appears to be a mixture of lead found in the PVC pipes, scrapings from other handpump components and industrial or lead based petrol (likely in the form of air particulates). Further analysis would be required to definitively identify the source of the lead found in the water samples but the initial analysis suggests that the handpump components are a likely candidate. However, it is important to re-emphasize that lead concentrations in the waters analysed were not found at levels that exceed WHO guideline or Nigerian standards, although some studies suggest that there is no safe concentration for lead in potable water supplies. Recommendations for further work to understand the discrepancies between laboratory results and the origin of lead are as follows: 1. More detailed inter-laboratory comparison. Certified water quality standards and solutions with known element concentrations should be prepared at BGS and analysed independently by all three laboratories. No standard solutions were sent to the Nigerian laboratories in the preliminary study. 2. Further collection and analysis of water quality samples from a larger sample of handpump and other sources to better establish a baseline for total and dissolved Pb and Cd concentrations. 3. More extensive and detailed Pb isotope sampling and analysis including collection of a range of end members from the local area (i.e. air particulate samples)

UK Geoenergy Observatories : Glasgow baseline groundwater and surface water chemistry dataset release September 2020 - May 2021

This report describes baseline water chemistry sampling and analysis results for groundwater and surface water at the United Kingdom Geoenergy Observatory (UKGEOS) in Glasgow between September 2020 and May 2021. The report accompanies the Glasgow Observatory groundwater chemistry data release and the Glasgow Observatory surface water chemistry data release for the same periods. While the reporting period is nine months long, the global Covid-19 pandemic meant sampling was not always possible during this time. The groundwater data release contains data from six monthly sampling rounds, and the surface water data release contains data from three to five monthly sampling rounds (site dependant). The Glasgow Observatory comprises twelve boreholes drilled into the main hydrogeological units, known as target units. These are the superficial deposits, bedrock, Glasgow Upper mine workings and Glasgow Main mine workings. The ten boreholes used for groundwater sampling are located at the Cuningar Loop in South Lanarkshire. There are two additional boreholes in the Observatory, one seismic monitoring borehole in Dalmarnock in the east end of Glasgow, and one borehole used for sensor testing. Three boreholes are drilled into the superficial deposits, two into the unmined bedrock, three into the Glasgow Upper mine workings and two into the Glasgow Main mine workings. The boreholes are designed to assist geological and hydrogeological characterisation, including baseline water chemistry monitoring, and to act as mine water abstraction and reinjection wells. The aims of the Observatory are to: 1) provide baseline environmental characterisation, 2) assess changes in ambient conditions induced by mine water abstraction/re-injection cycles and, 3) provide data and evidence to de-risk low-temperature shallow mine water heat energy and heat storage in former coal mine workings. Groundwater sampling was conducted using either a submersible or bladder pump. Field parameters (pH, specific electrical conductance (SEC), redox potential (Eh) and dissolved oxygen (DO)) were measured in a flow-through cell. The flow-through cell was discharged to a plastic beaker containing a thermometer probe. Field parameters were measured for a period of 20 minutes and at least three readings were taken five minutes apart. After field parameters were taken, the flow cell was disconnected and samples were taken directly from the pump discharge tube. Field alkalinity was measured by titration against H2SO4. Groundwater samples were analysed for: major, minor, and trace elements, chromium speciation (Cr (III) and Cr (VI)), non-purgeable organic carbon (NPOC) and total inorganic carbon (TIC), polycyclic aromatic hydrocarbons (PAH), total petroleum hydrocarbons (TPH), volatile organic compounds (VOC), stable isotopes - deuterium (δ2H), oxygen 18 (δ18O) and carbon 13 of dissolved inorganic carbon (DIC) (δ13CDIC), ammonium (NH4), methane, ethane and carbon dioxide (CH4, C2H6, CO2), chlorofluorocarbons (CFC-12 and CFC-11), sulphur hexafluoride (SF6), and sulphide (S2-). The pH of groundwater samples (range 6.78 – 7.81) is circum-neutral to alkaline, with a similar range across all target units. Groundwater from all four lithologies is highly mineralised with median SEC values >1470 μS/cm. GGA01, installed in the Glasgow Upper mine working, had the most highly mineralised groundwater with a range of 2697 μS/cm – 3002 μS/cm. This range is significantly higher than those found in the groundwater of other boreholes screened into the Glasgow Upper mine workings: GGA04 (1597 μS/cm – 1669 μS/cm) and GGA07 (1664 μS/cm – 1756 μS/cm). The Glasgow Main mine workings boreholes, GGA05 and GGA08, had a combined SEC range of 1570 μS/cm – 1658 μS/cm. The range of recorded groundwater temperatures is largest in the superficial deposits (10.8°C – 15.1°C), reflecting the near-surface environment. The bedrock and mine workings all have similar ranges (bedrock 10.3°C – 12.6 °C, Glasgow Upper mine workings 10.6 °C – 13.3 °C, Glasgow Main mine workings 10.5 °C – 13.6 °C). In all target units the dissolved oxygen concentration is very low, the medians range from 0.23 mg/L to 0.31 mg/L. In general major elements and physio-chemical parameters measured in the groundwater samples have concentration ranges similar to those found in bedrock and mine workings across the Carboniferous sedimentary aquifers of the Midland Valley (Ó Dochartaigh et al., 2011). The water from most groundwater samples is unchanged from pumping tests conducted in early 2020 (Palumbo-Roe et al., 2021). Groundwaters are HCO3 type, with no dominant cation. However, groundwater in GGA01 has evolved since the pumping test and now has Ca-SO4 type water. Oxidation of iron sulphide minerals (e.g. pyrite) could have caused the dominance of the SO4 anion in GGA01 groundwaters. Dissolved organic carbon (as NPOC) has the largest range and the highest concentrations in the superficial deposits’ groundwaters (3.44 mg/L – 16.49 mg/L), the highest concentrations were all found in the groundwater at GGB04 (4.51 mg/L – 16.49 mg/L). Broadly similar concentrations were recorded in the bedrock (1.03 mg/L – 3.37 mg/L) and mine workings (Glasgow Upper mine workings: 1.91mg/L – 3.16 mg/L, Glasgow Main mine workings: 2.10 mg/L – 3.04 mg/L). The Ammonium (NH4) concentrations are high in all Glasgow Observatory groundwaters, with similar median values in all target units (12.9 mg/L – 13.5 mg/L). There was a large concentration range of trace elements in the Glasgow Observatory groundwaters, but there was no clear distribution. The lowest concentrations, and smallest ranges of each trace element tended to be in the Glasgow Main groundwaters, while the highest median and max concentrations of each trace element were found across the superficial deposits, bedrock and Glasgow Upper groundwaters. Some PAHs were detected in the superficial and bedrock boreholes, with TPH detected in low concentrations in all units at least once during the sampling period. VOCs were detected in the superficial deposits and Glasgow Main mine workings. Water stable isotopes, carbon 13 of DIC and residence time data were consistent with findings from the pumping test results (Palumbo-Roe et al., 2021). Groundwaters are recharged by modern recharge from local rainfall. Median concentrations of dissolved CH4 in the groundwaters range from 21 μg/L in the superficial deposits to 202 μg/L in the Glasgow Upper mine workings. These values lie within the upper range of groundwaters reported in other studies from Carboniferous sedimentary rocks in the Midland Valley of Scotland (Ó Dochartaigh et al., 2011). The highest concentration was found in borehole GGA04 (991 μg/L) and the superficial deposit borehole GGA09r, the latter being consistent with previous data (Palumbo-Roe et al., 2021). Dissolved CO2 has a median value of 116 mg/L with little variation between units. Cluster analysis revealed that the superficial deposits, the bedrock, the mine workings and the surface water samples are each clustered into statistically distinct groups. Borehole GGB04 generally clusters separately from the other boreholes drilled into the superficial deposits. GGB04 displays clear differences in concentrations and trends during the monitoring for a number of trace elements including Co, Mn, Fe, Ni and also in concentrations of NH4. It is possible that these differences are driven by migration of elements from the made ground at the site into the superficial deposits. Borehole GGA01, drilled into the Glasgow Upper mine workings is also distinct. This can be explained by the behaviour and concentrations of major and trace elements during the monitoring period. Trace elements As, Ba, Co, Fe, Li, Mn, Mo, Ni, Rb, Si, Sr, U and W, all have different concentrations to those observed in the other Glasgow Upper mine working boreholes. The packed waste that GGA01 is drilled into may act as a source for the elevated trace elements. Surface water samples were taken using an angular beaker and telescopic rod. Samples were taken from the River Clyde and the Tollcross Burn. Surface water samples were analysed for: major, minor, and trace elements, chromium species (Cr (III) and Cr (VI)), non-purgeable organic carbon (NPOC) and total inorganic carbon (TIC), polycyclic aromatic hydrocarbons (PAH), total petroleum hydrocarbons (TPH), and stable isotopes - deuterium (δ2H), oxygen 18 (δ18O) and carbon 13 of dissolved inorganic carbon (DIC) (δ13CDIC). While both the Clyde and Tollcross Burn have a near-neutral to alkaline pH and show a narrow range in pH values, the pH values measured at the Tollcross Burn tend to be higher (median 8.4 from the Tollcross Burn and 7.9 from the Clyde). The waters all follow a similar temporal trend, with the highest value each month measured at the Tollcross Burn. The SEC measurements are higher in the Tollcross Burn samples (median 953 μs/cm) than those measured in the River Clyde samples (median 385 μs/cm). The surface water samples all have similar major ion proportions. The River Clyde samples are Ca-HCO3 type. The samples taken from the Tollcross Burn are also Ca-HCO3 type, but can be distinguished from River Clyde samples as they have lower Ca concentrations and higher HCO3 concentrations. Most trace elements are present in higher concentrations in the River Clyde than in the Tollcross Burn; exceptions to this are Sr, B, and Rb, which are higher in the Tollcross Burn, and Co, Ni, Zn, As, Y, and Sb, which have similar concentrations in both watercourses. With the exception of Cr, the trace element concentrations are similar between all sites on the River Clyde, which would be expected given these sites are all on a relatively short stretch of the same river. The Cr concentrations are much higher at the sampling site closest to a former chemical works than elsewhere within the observatory. In general, the surface water results are consistent with findings from previous work (Fordyce et al., 2021)