Using CFCs and SF6 for groundwater dating : a SWOT analysis

A knowledge of the residence time of groundwater is of importance in understanding key issues in the evolution of water quality. Chlorofluorocarbons (CFCs) and sulphur hexafluoride (SF6) offer a convenient way of dating waters up to ~60 yrs old. In contrast to tritium, these gases are well-mixed in the atmosphere so their input functions are much less problematic. While any one of these gases can in principle provide a groundwater age, when two or more are measured on water samples the potential exists to distinguish between different modes of flow including piston flow, exponential flow and simple endmember mixing. As with all groundwater dating methods, caveats apply. Factors such as recharge temperature and elevation must be reasonably well-constrained. Mainly for SF6, the phenomenon of ‘excess air’ also requires consideration. Mainly for the CFCs, local sources of contamination need to be considered, as do redox conditions. For both SF6 and the CFCs, the nature and thickness of the unsaturated zone need to be factored into residence time calculations. This paper attempts a balanced look at the pros and cons of the trace-gas dating method

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)

UK Geoenergy Observatories : Glasgow baseline groundwater and surface water chemistry dataset release June 2021 - January 2022

This report follows the Glasgow baseline groundwater and surface-water chemistry dataset release report September 2020 – May 2021 (data release/ monitoring period 1) (Bearcock et al., 2022), and describes baseline water chemistry sampling and analysis results for groundwater and surface water at the United Kingdom Geoenergy Observatory (UKGEOS) in Glasgow between June 2021 and January 2022. The report accompanies the Glasgow Observatory groundwater chemistry data release and the Glasgow Observatory surface water chemistry data release for the same periods (data release/ monitoring period 2). The monitoring period is eight months long, with six rounds of surface water and groundwater sampling during this time. Sampling during non-consecutive months was a result of COVID-19 restrictions and construction activities at site. The Glasgow Observatory comprises twelve boreholes drilled into the main hydrogeological units, known as target horizons. 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, reduced iron (Fe), non-purgeable organic carbon (NPOC) and total inorganic carbon (TIC), polycyclic aromatic hydrocarbons (PAH), total petroleum hydrocarbons (TPH), volatile organic compounds (VOC), 2H and 18O abundance in water (δ2H and δ18O), 13C abundance in dissolved inorganic carbon (DIC) (δ13CDIC), ammonium (NH4), dissolved gases (methane, ethane and carbon dioxide (CH4, C2H6, CO2)), noble gases (helium, neon, argon, krypton, and xenon (He, Ne, Ar, Kr and Xe)), chlorofluorocarbons (CFC-12 and CFC-11), sulphur hexafluoride (SF6), and sulphide (S2-). The pH of groundwater samples (range 6.6 – 7.4) is circum-neutral, with a similar range across all target horizons. Groundwater from all four horizons is highly mineralised with median SEC values 1440 μS/cm - 1670 μS/cm. GGA01, installed in the Glasgow Upper mine working, had the most highly mineralised groundwater with a range of 2930 μS/cm – 3140 μS/cm. The range of recorded groundwater temperatures is largest in the superficial deposits (11.0°C – 16.6°C). The bedrock and mine workings groundwaters all have similar temperatures, and a narrower range of 10.1°C – 13.4 °C. In all target horizons the dissolved oxygen concentration is very low, all DO values are ≤0.81 mg/L. In general major elements and physico-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 chemistry of most groundwater samples is unchanged from pumping tests conducted in early 2020 (Palumbo-Roe et al., 2021), and the previous period of baseline monitoring that spanned the period from September 2020 to May 2021 (Bearcock et al., 2022). Groundwaters are generally HCO3 type, with no dominant cation. The exception is GGA01, where groundwaters changed from HCO3 type during the pumping test to Ca-SO4 type at the start of the previous round of monitoringThe Glasgow Observatory comprises twelve boreholes drilled into the main hydrogeological units, known as target horizons. 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, reduced iron (Fe), non-purgeable organic carbon (NPOC) and total inorganic carbon (TIC), polycyclic aromatic hydrocarbons (PAH), total petroleum hydrocarbons (TPH), volatile organic compounds (VOC), 2H and 18O abundance in water (δ2H and δ18O), 13C abundance in dissolved inorganic carbon (DIC) (δ13CDIC), ammonium (NH4), dissolved gases (methane, ethane and carbon dioxide (CH4, C2H6, CO2)), noble gases (helium, neon, argon, krypton, and xenon (He, Ne, Ar, Kr and Xe)), chlorofluorocarbons (CFC-12 and CFC-11), sulphur hexafluoride (SF6), and sulphide (S2-). The pH of groundwater samples (range 6.6 – 7.4) is circum-neutral, with a similar range across all target horizons. Groundwater from all four horizons is highly mineralised with median SEC values 1440 μS/cm - 1670 μS/cm. GGA01, installed in the Glasgow Upper mine working, had the most highly mineralised groundwater with a range of 2930 μS/cm – 3140 μS/cm. The range of recorded groundwater temperatures is largest in the superficial deposits (11.0°C – 16.6°C). The bedrock and mine workings groundwaters all have similar temperatures, and a narrower range of 10.1°C – 13.4 °C. In all target horizons the dissolved oxygen concentration is very low, all DO values are ≤0.81 mg/L. In general major elements and physico-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 chemistry of most groundwater samples is unchanged from pumping tests conducted in early 2020 (Palumbo-Roe et al., 2021), and the previous period of baseline monitoring that spanned the period from September 2020 to May 2021 (Bearcock et al., 2022). Groundwaters are generally HCO3 type, with no dominant cation. The exception is GGA01, where groundwaters changed from HCO3 type during the pumping test to Ca-SO4 type at the start of the previous round of monitoring (September 2020). During this monitoring period the concentrations of Ca and SO4 in GGA01 have continued to increase, albeit at a slowing rate, while HCO3 concentrations, which had initially fallen, are slowly increasing. Oxidation of sulphide minerals (e.g. pyrite) could have caused the dominance of the SO4 anion in GGA01 groundwaters. Dissolved organic carbon (as NPOC) is present in the range 1.05 mg/L to 5.46 mg/L, except for one outlier of 23.5 mg/L at GGA01. NPOC concentrations in the superficial deposits, with a median 4.39 mg/L, are at the upper end of this range, while all other target horizons have similar, lower, median values (medians from 2.32 mg/L to 2.54 mg/L). Groundwater samples from two boreholes have low ammonium (NH4) concentrations throughout the monitoring period (GGB04 in the superficial deposits and bedrock borehole GGA03r have a combined median of 3.15 mg/L). The remaining groundwaters in the Glasgow Observatory have high NH4 concentrations (combined median 23.2 mg/L). There was a large concentration range of trace elements in the Glasgow Observatory groundwaters. In general, the lowest concentrations were found in groundwaters from the Glasgow Main mine workings. In contrast the highest trace element concentrations were found in the groundwaters from the Glasgow Upper mine workings and the superficial deposits. TPH was detected in low concentrations in all units at some point during the sampling period. VOCs were not detected in any groundwater sample. Water stable isotopes (δ2H and δ18O), inorganic carbon δ13C and groundwater residence time data were consistent with findings from the pumping test results and previous monitoring period (Bearcock et al., 2022; Palumbo-Roe et al., 2021). Groundwaters are recharged by modern recharge from local rainfall. Median concentrations of dissolved methane (CH4) in the groundwaters range from 16.6 μg/L in the superficial deposits to 224 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). Dissolved ethane (C2H6) was below detection limits in all but one sample (5.2 μg/L at GGA01). Dissolved CO2 has a median value of 141 mg/L with little variation between units. Water chemistry cluster analysis shows that the superficial deposits, bedrock, mine working, and surface water samples cluster into statistically distinct groups. Notable exceptions are groundwaters from GGA01 which form their own separate group, and GGB05 groundwaters from the bedrock horizon which group with the mine workings. 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, non-purgeable organic carbon (NPOC) and total inorganic carbon (TIC), polycyclic aromatic hydrocarbons (PAH), total petroleum hydrocarbons (TPH), 2H and 18O abundance in water (δ2H and δ18O) and carbon 13 abundance in dissolved inorganic carbon (DIC) (δ13CDIC), . While both the Clyde and Tollcross Burn have a near-neutral to alkaline pH (7.3 – 8.7), the pH values measured at the Tollcross Burn tend to be higher (median 8.3 from the Tollcross Burn and 7.7 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 872 μs/cm) than those measured in the River Clyde samples (median 372 μs/cm). Surface water samples are all generally Ca-HCO3 type. The samples taken from the Tollcross Burn tend to have a greater HCO3 proportion than the river Clyde samples. Most detected trace elements are present in higher concentrations in the River Clyde than in the Tollcross Burn. 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 (median 4.18 μg/L) than elsewhere within the Glasgow Observatory (median 0.4 μg/L). In general, the surface water results are consistent with findings from previous work (Bearcock et al., 2022; Fordyce et al., 2021). (September 2020). During this monitoring period the concentrations of Ca and SO4 in GGA01 have continued to increase, albeit at a slowing rate, while HCO3 concentrations, which had initially fallen, are slowly increasing. Oxidation of sulphide minerals (e.g. pyrite) could have caused the dominance of the SO4 anion in GGA01 groundwaters. Dissolved organic carbon (as NPOC) is present in the range 1.05 mg/L to 5.46 mg/L, except for one outlier of 23.5 mg/L at GGA01. NPOC concentrations in the superficial deposits, with a median 4.39 mg/L, are at the upper end of this range, while all other target horizons have similar, lower, median values (medians from 2.32 mg/L to 2.54 mg/L). Groundwater samples from two boreholes have low ammonium (NH4) concentrations throughout the monitoring period (GGB04 in the superficial deposits and bedrock borehole GGA03r have a combined median of 3.15 mg/L). The remaining groundwaters in the Glasgow Observatory have high NH4 concentrations (combined median 23.2 mg/L). There was a large concentration range of trace elements in the Glasgow Observatory groundwaters. In general, the lowest concentrations were found in groundwaters from the Glasgow Main mine workings. In contrast the highest trace element concentrations were found in the groundwaters from the Glasgow Upper mine workings and the superficial deposits. TPH was detected in low concentrations in all units at some point during the sampling period. VOCs were not detected in any groundwater sample. Water stable isotopes (δ2H and δ18O), inorganic carbon δ13C and groundwater residence time data were consistent with findings from the pumping test results and previous monitoring period (Bearcock et al., 2022; Palumbo-Roe et al., 2021). Groundwaters are recharged by modern recharge from local rainfall. Median concentrations of dissolved methane (CH4) in the groundwaters range from 16.6 μg/L in the superficial deposits to 224 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). Dissolved ethane (C2H6) was below detection limits in all but one sample (5.2 μg/L at GGA01). Dissolved CO2 has a median value of 141 mg/L with little variation between units. Water chemistry cluster analysis shows that the superficial deposits, bedrock, mine working, and surface water samples cluster into statistically distinct groups. Notable exceptions are groundwaters from GGA01 which form their own separate group, and GGB05 groundwaters from the bedrock horizon which group with the mine workings. 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, non-purgeable organic carbon (NPOC) and total inorganic carbon (TIC), polycyclic aromatic hydrocarbons (PAH), total petroleum hydrocarbons (TPH), 2H and 18O abundance in water (δ2H and δ18O) and carbon 13 abundance in dissolved inorganic carbon (DIC) (δ13CDIC), . While both the Clyde and Tollcross Burn have a near-neutral to alkaline pH (7.3 – 8.7), the pH values measured at the Tollcross Burn tend to be higher (median 8.3 from the Tollcross Burn and 7.7 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 872 μs/cm) than those measured in the River Clyde samples (median 372 μs/cm). Surface water samples are all generally Ca-HCO3 type. The samples taken from the Tollcross Burn tend to have a greater HCO3 proportion than the river Clyde samples. Most detected trace elements are present in higher concentrations in the River Clyde than in the Tollcross Burn. 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 (median 4.18 μg/L) than elsewhere within the Glasgow Observatory (median 0.4 μg/L). In general, the surface water results are consistent with findings from previous work (Bearcock et al., 2022; Fordyce et al., 2021)

UK Geoenergy Observatories : Glasgow borehole test pumping - groundwater chemistry

In 2015, the British Geological Survey (BGS) and the Natural Environment Research Council (NERC) were tasked with developing new centres for research into the subsurface environment to aid the responsible development of new low-carbon energy technologies in the United Kingdom (UK) and internationally. Glasgow is one of two UK Geoenergy Observatories (UKGEOS) (Figure 1). The Glasgow Observatory comprises a network of boreholes across five sites into the superficial deposits, mined and unmined bedrock in the Dalmarnock area in the east of Glasgow City (Site 10 on Figure 1b) and at the Cuningar Loop on the River Clyde in Rutherglen, South Lanarkshire (Sites 1, 2, 3 and 5 on Figure 1b). These were designed to characterise the geological and hydrogeological setting as a research infrastructure to de-risk key technical barriers to lowtemperature shallow mine water heat/storage in an urbanised former mine setting (Monaghan et al. 2017, 2019). The borehole network is intended also for baseline monitoring to assess the environmental status before and during the lifetime of the project. Figure 1c shows the details of the 11 boreholes located at the Cuningar Loop. Test pumping was carried out at nine of the Cuningar Loop boreholes in January and February 2020 to characterise the hydraulic properties of the target aquifer horizons (mine workings, bedrock, and superficial deposits), and to determine the extent to which these are hydraulically connected (Shorter et al. 2021; Figure 1c). Groundwater samples were collected during constantrate pumping tests and analysed to provide an initial hydrochemical characterisation of the aquifers and, where more than one sample was obtained during the test, to measure changes in selected constituents during pumping, to complement observed hydraulic responses. Fifteen groundwater samples were obtained and were analysed to determine the concentrations of selected chemical parameters at the BGS and associated laboratories. This report details the groundwater sampling protocols used during the test pumping, the analysis methods, and the groundwater hydrochemistry. The report accompanies the dataset: UKGEOS Glasgow Test Pumping Groundwater Chemistry Data Release

Families’ perceptions of and experiences related to a pediatric weight management program.

Objective: To examine parents' and children's perceptions of and experiences related to a Parents as Agents of Change (PAC) intervention for managing pediatric obesity. Methods: Ten families were recruited from a PAC intervention. Participants were interviewed before (10 adults and 9 children), during (9 adults and 8 children), and after (8 adults) the intervention. Results: Before the intervention, families reported goals to increase physical activity, plan and eat healthier meals, reduce screen time, and lose weight. During the intervention, families described different approaches to making behavior changes depending on who assumed responsibility (parent, child, or shared responsibility). After the intervention, group setting, goal setting, and portion size activities were viewed positively. Suggestions for improvement included engaging children and reducing intervention length. Conclusions and Implications: Practitioners delivering PAC interventions should discuss families' goals and concerns, and who is responsible for making lifestyle changes. Practical activities are valuable. The length of interventions and engagement of children should be considere

Branching Fractions for D0 -> K+K- and D0 -> pi+pi-, and a Search for CP Violation in D0 Decays

Using the large hadroproduced charm sample collected in experiment E791 at Fermilab, we have measured ratios of branching fractions for the two-body singly-Cabibbo-suppressed charged decays of the D0: (D0 -> KK)/(D0 -> Kpi) = 0.109 +- 0.003 +- 0.003, (D0 -> pipi)/(D0 -> Kpi) = 0.040 +- 0.002 +- 0.003, and (D0 -> KK)/(D0 -> pipi) = 2.75 +- 0.15 +- 0.16. We have looked for differences in the decay rates of D0 and D0bar to the CP eigenstates K+K- and pi+pi-, and have measured the CP asymmetry parameters A_CP(K+K-) = -0.010 +- 0.049 +- 0.012 and A_CP(pi+pi-) = -0.049 +- 0.078 +- 0.030, both consistent with zero.Comment: 10 Postscript pages, including 2 figures. Submitted to Phys. Lett.

Search for CP Violation in Charged D Meson Decays

We report results of a search for CP violation in the singly Cabibbo-suppressed decays D+ -> K- K+ pi+, phi pi+, K*(892)0 K+, and pi- pi+ pi+ based on data from the charm hadroproduction experiment E791 at Fermilab. We search for a difference in the D+ and D- decay rates for each of the final states. No evidence for a difference is seen. The decay rate asymmetry parameters A(CP), defined as the difference in the D+ and D- decay rates divided by the sum of the decay rates, are measured to be: A(CP)(K K pi) = -0.014 +/- 0.029, A(CP)(phi pi) = -0.028 +/- 0.036, A(CP)(K*(892) K) = -0.010 +/- 0.050, and A(CP)(pi pi pi) = -0.017 +/- 0.042.Comment: 13 pages, 5 figures, 1 table; Elsevier LaTe

Search for Rare and Forbidden Dilepton Decays of the D+, Ds, and D0 Charmed Mesons

We report the results of a search for flavor-changing neutral current, lepton-flavor violating, and lepton-number violating decays of D+, Ds, and D0 mesons (and their antiparticles) into modes containing muons and electrons. Using data from Fermilab charm hadroproduction experiment E791, we examine the pi,l,l and K,l,l decay modes of D+ and Ds and the l+l- decay modes of D0. No evidence for any of these decays is found. Therefore, we present branching-fraction upper limits at 90% confidence level for the 24 decay modes examined. Eight of these modes have no previously reported limits, and fourteen are reported with significant improvements over previously published results.Comment: 12 pages, 3 figures, LaTeX, elsart.cls, epsf.sty, amsmath.sty Submitted to Physics Letters

Measurement of the form-factor ratios for D+ --> K* l nu

The form factor ratios rv=V(0)/A1(0), r2=A2(0)/A1(0) and r3=A3(0)/A1(0) in the decay D+ --> K* l nu, K* -->K-pi+ have been measured using data from charm hadroproduction experiment E791 at Fermilab. From 3034 (595) signal (background) events in the muon channel, we obtain rv=1.84+-0.11+-0.09, r2=0.75+-0.08+-0.09 and, as a first measurement of r3, we find 0.04+-0.33 +-0.29. The values of the form factor ratios rv and r2 measured for the muon channel are combined with the values of rv and r2 that we have measured in the electron channel. The combined E791 results for the muon and electron channels are rv=1.87+-0.08+-0.07 and r2=0.73+-0.06+-0.08.Comment: 9 pages + 3 figures ; submitted to PL

Asymmetries between the production of D+ and D- mesons from 500 GeV/c pi- nucleon interactions as a function of xF and pt**2

We present asymmetries between the production of D+ and D- mesons in Fermilab experiment E791 as a function of xF and pt**2. The data used here consist of 74,000 fully-reconstructed charmed mesons produced by a 500 GeV/c pi- beam on C and Pt foils. The measurements are compared to results of models which predict differences between the production of heavy-quark mesons that have a light quark in common with the beam (leading particles) and those that do not (non-leading particles). While the default models do not agree with our data, we can reach agreement with one of them, PYTHIA, by making a limited number of changes to parameters used