Hydraulic characterisation of the tailings associated with the abandoned mine at Frongoch, Mid-Wales

This report describes the material classification and results of field and laboratory hydraulic testing of tailings from the Frongoch Tailings Lagoon, situated immediately to the south of the abandoned Frongoch mine site in mid-Wales. The results are considered in the context of the conceptual site model

A hydrochemical assessment of groundwater-surface water interaction in the Woodham Burn, a Magnesian Limestone catchment in County Durham

The interaction between groundwater and surface water, in particular in the hyporheic zone, is recognised to influence chemical fluxes between river and groundwater and to transform reactive chemistries such as nutrients or legacy contaminants. Characterising this connectivity in the Skerne catchment in Co. Durham has been recognised to be important by the Environment Agency (EA) in order to protect the underlying Magnesian Limestone aquifer and dependent features. Of particular concern is the presence of an eastward moving, sulphate-rich, mine water plume related to the recovery of groundwater levels in the underlying Coal Measures strata and mine workings. Building on a previous investigation across the entire Skerne catchment, this work, in collaboration with the EA, aimed to understand the existence of hydraulic connection between groundwater and surface water and the hyporheic zone characteristics in a 500 m stretch of the Woodham Burn, a tributary of the Skerne. We have employed multiple methods, both at the reachscale and smaller sediment-scale, for identifying source areas of sulphate to the stream, characterising the subsurface flow and estimating the controls on sulphate fluxes and potential natural attenuation. The Woodham Burn was monitored during three sampling events in: April 2018, August 2018, and February 2019. The stream water chemistry survey has confirmed sulphate concentrations in excess of the drinking water standard of 250 mg/l, with a median of 510 mg/l in the surface water, range 235- 790 mg/l. Stream flow measurements complementary to the water chemistry analysis were not possible and therefore loads (flow multiplied by concentration) of sulphate could not be calculated. Given the lack of tributaries, the changes in surface water chemistry were, nevertheless, useful to attribute the observed changes to groundwater losses or gains, where groundwater and surface water concentrations are significantly different. The spatial survey of downstream changes in stream water chemistry has delineated a sulphate-rich recharge zone within the study reach, which is very localised, with sulphate concentrations up to 800 mg/l and electrical conductivity of 2000 µS/cm. The source appears to be groundwater discharging directly into the stream channel and in the form of a seep on the western bank. The contribution of this source to the stream was quantified as up to 50 percent increase in dissolved sulphate in surface water. An additional area potentially recharging sulphate to the stream, more diffuse in nature, was identified through analysis of the water-soluble fraction of soil samples collected by augers and additional bank seepage measurements and it corresponds to the northern banks upstream of the first monitoring point. Temperature vertical profiling of the riverbed along the 500 m study reach together with a corresponding survey of specific electrical conductivity (SEC) variation in the surface water were used to further detect areas of potential flow of surface water to groundwater or flow of groundwater to surface water, and to inform the site selection for the monitoring of subsurface flow at smaller scale with piezometers and minipiezometers. At four locations, piezometers were installed with data loggers to provide continuous observations of hydraulic heads, temperature, and (at two points) SEC: two paired piezometers of shallow (0.4 m) and deeper (1.4 m) depth at three of the locations and only a single shallow piezometer for one site. Due to the loss of the surface water logger after a storm event, precise water level fluctuations in Woodham Burn were unknown, and recorded fluctuations in the subsurface were more difficult to correlate. At the same locations, plus an additional one, a network of multilevel minipiezometers (two to three per site) were driven into the hyporheic zone to a fixed depth of 0.9 m below the riverbed and used to draw pore water from 10, 20, 50 and 90 cm depth. The evidence from vertical gradients of conservative elements, chloride and lithium, measured in each multilevel minipiezometer, and evidence from the diurnal temperature variations and hydraulic head from logged data, converged to indicate an increase of hyporheic exchange flow (HEF) moving downstream in the burn, corresponding to the transition in the superficial deposits from alluvium to lacustrine deposits, while the most upstream sites showed the near absence of HEF and at least one clearly gaining reach in correspondence of the sulphate-rich instream discharge. ix Evaluation of natural attenuation in the hyporheic zone was carried out via comparison of conservative and non-conservative solute gradients. In most of the sites where there was sufficient HEF, both nitrate and sulphate showed various extents of non-conservative behaviour compared to chloride in the subsurface flow. In particular, the most significant losses of nitrate were observed in piezometers at the most downstream section of the reach (-48% to -98%). Sulphate losses were generally lower than those for nitrate and varied greatly (9% to 100%), often larger at depth. Although nitrate and sulphate losses were observed during surface water downwelling in the studied hyporheic zone, a correspondent decrease in stream water concentrations was not evident. It is recommended to test the significance of hyporheic natural attenuation to improve the stream water quality at catchment scale, by carrying out surface water flow measurements combined with water quality analysis, which enable calculation of mass gains and losses to identify the net flux integrated over the entire stream. The analysis of the deep hyporheic zone chemistry, the least affected by shallow hyporheic exchange of downwelling surface water, gave insights into hydrochemical differences along the reach and indicates potentially distinct groundwater sources. These differences appear to be related to geology: the most upstream monitoring locations sited on the alluvium have greater similarities to the Magnesian Limestone aquifer, as inferred by cluster analysis with additional EA groundwater monitoring boreholes. As previously identified points of limited HEF and groundwater dominated hyporheic water, these locations plausibly represent a groundwater recharge zone. On the other hand, the most downstream points located on the lacustrine deposits show a different hyporheic zone composition, distinctly closer to hyporheic waters previously sampled from Rushyford Beck, also on lacustrine deposits. Beside these hydrochemical differences, a greater one is represented by the discrete spring (Bubbly Spring) discharging through the stream bed and western stream banks. Its chemistry has strong similarities to other seeps in the burn and also to Stony Hall C borehole water, which is sourced from the Coal Measures. The spring composition (Mg-SO4 water type) was very stable throughout the monitoring period and distinctively enriched in SO4 (median 811 mg/l) together with Sr (median 984 μg/l) , Li (median 162 μg/l), Rb (median 7.19 μg/l) and U (median 4.04 μg/l) compared to all the other waters in Woodham Burn, while it was lower in Si, Ba, Mn and Fe. Two, both plausible, reaction paths can explain the spring composition: one is gypsum dissolution and dedolomitisation, the other one is acid neutralisation of coal mine water through the dissolution of dolomite. To explain the physical processes underpinning the emergence of this groundwater enriched in sulphate and the origin of this sulphate further investigation is needed. In particular residence time studies and isotope analysis of water and dissolved sulphate are recommended. To gain a broader perspective on groundwater discharge areas a spatial hydrochemical survey of springs and seeps in the catchment should also be undertaken

Investigation of sulphate sulphur isotope variations in the Skerne Magnesian Limestone water body

This report presents the results of a sulphur isotope investigation undertaken in the Skerne catchment, located in County Durham, north of Darlington, to investigate the source of groundwater sulphate in the Magnesian Limestone Aquifer. Groundwater and surface waters in the catchment are at risk from a number of current and historic anthropogenic activities. Sulphate is the biggest risk to the public water supplies; as there is currently no cost-effective treatment available and it could render supplies unusable. The elevated sulphate could be both naturally occurring, due to the presence of gypsum or anhydrite bands in the Magnesian Limestone, or it could be due to abandoned coal mine water, or even saline intrusion pollution. Because of the large difference in the sulphate sulphur isotope composition expected between “marine sulphate”, including sulphate derived from marine evaporites, and “non-marine sulphate” derived from the oxidation of sulphide in the coal seams and mine workings, sulphur isotopes were considered promising tracers to discern mine water sources from natural Permian evaporite sources of sulphate. A survey was carried out at 28 sites where groundwater was sampled in July 2018 from boreholes in the Magnesian Limestone Aquifer and in the Coal Measures, following a pilot study comprising 7 boreholes in July 2017. A small number of surface waters, hyporheic zone waters, springs, and soil leachates, sampled during 2017-2018, were also analysed for sulphur isotopes to complement the borehole data. This has allowed the characterisation of the sulphur isotope composition of potential sources of dissolved sulphate. Most of the Magnesian Limestone aquifer groundwaters cluster close to the Global Meteoric Water Line (GMWL) on the dual water δ 18O and δ2H graph with no evidence of mixing with Narich coal mine water, the latter being more depleted in 18O and 2H; there is a small number of boreholes immediately in proximity of the coal seam boreholes, clearly showing signs of water mixing. With higher δ18O and δ2H than the main Magnesian Limestone group, and slightly offset from the GMWL, is also a small group of Magnesian Limestone boreholes. Repeated sampling would better discern the different recharge paths suggested by this single sampling event in July 2018. Groundwaters associated with the worked and unworked coal seam boreholes in this study are of two water types: sodium sulphate (Na–SO4) and sodium bicarbonate (Na–HCO3) waters, variably enriched in dissolved sulphate. Two δ 34S measurements of the dissolved sulphate in the Na–SO4 coal seam boreholes are +13.1‰ and +23.4‰. The lack of the more typical 34S-depleted sulphate derived from the oxidation of pyrite is hence apparent. A similar range of high sulphate δ 34S values has been described in recent studies, and attributed to deep coal mine systems. From a review of published δ34S values for marine evaporites, groundwaters containing sulphate solely derived from the dissolution of Permian marine evaporites are characterised by 34Senriched sulphate (δ34S values range from +8.2 to +11.1‰). There is, therefore, less of a contrasting isotope signature between potential “evaporite” and “coal mine water” end-members. For example, one sample of coal mine water with δ 34S values of +13.1‰ is not too dissimilar to the average Permian evaporite sulphate with δ 34S value of around +10‰. This makes discrimination of the dissolved sulphate sources based on sulphur isotope less certain, especially at low sulphate concentrations. To help the data interpretation, we have modelled the sulphate and sulphur isotope compositions of mixtures of hypothetical end-members and used the evidence from these simulations to constrain possible groundwater contributions and mixing. In particular we simulate how the HARDWICK HALL borehole, representing the Magnesian Limestone aquifer background, with a sulphate concentration of 89 mg/l, and a δ34S value of +1.0‰, evolves during mixing with the following end-members: i) the coal mine waters in this study, ii) a Permian evaporite source, iii) seawater and iv) acid mine drainage. A summary of the data interpretation based on the above modelling is as follows. Over the mine plume area, inputs of coal mine water-derived sulphate are significant in at least one Magnesian Limestone borehole, and detectable in others, supported by the water isotope δ 18O and δ2H data, indicating for these samples water mixing between the coal mine water and the Magnesian Limestone aquifer. Among the Magnesian Limestone boreholes, where gypsum or anhydrite were noted in the borehole logs, only DALTON PIERCY NO 3 and NO 6 boreholes have high sulphate concentrations and display constant δ 34S values of +10.2‰. Given how close this value is to the Permian evaporites’ δ34S values, it could be plausibly explained by a gypsum dissolution source, although a “coal mine water” contribution with a δ34S signature of +13‰ cannot be totally excluded, as shown by the mixing curves. Many of the Magnesian Limestone boreholes with a sulphate concentration around 100 mg/l (range 85–130 mg/l) are characterised instead by a low δ 34S range (-0.7 to +7.2‰). For most of these low sulphate Magnesian Limestone boreholes, uncertainties in discriminating the source of sulphate are higher. The contribution of sulphate from seawater is difficult to discern in the present data for the saline waters of HART RESERVOIR and HARTLEPOOL IND ESTATE REPLACEMENT boreholes, with similar δ34S values of +21.1‰ and +27‰, as they fall far away from the Seawater–Magnesian Limestone mixing line. Many samples fall far outside of these mixing envelopes, suggesting non-conservative behaviour of the sulphate. The very high δ34S and low sulphate concentrations can be interpreted as a possible sign of reduction of sulphates and enrichment in the heavier 34S isotope of the residual (low concentration) sulphate. Additional samples obtained during this study include: i) A spring in the Ford Formation from AYCLIFFE QUARRY to the south east of Aycliffe Village which provides an additional background sample characterised for sulphur isotopes. The water has a SO4 of 69 mg/l and a δ34S value of +2.3‰ and well resembles the composition of HARDWICK HALL borehole. ii) A Mg–SO4 spring, sampled in Woodham Burn and described in previous studies for its impact on the surface water quality because of its high sulphate concentrations of ~800 mg/l. It has a stable δ34S value of ~ +5.5‰. iii) a surface water impacted by mine water inflow with a Mg–SO4 composition, and a δ34S value of +6.9‰. The δ34S value of +5.5‰ of the Mg-SO4 spring at Woodham Burn points to a contribution of low δ 34S-sulphate, as expected from the oxidation of pyrite. These data support the mechanism, hypothesised in Palumbo-Roe et al. (2020) to account for the spring composition, of dissolution of dolomite in the presence of acidic water, where the source of acidity comes from coal mine water due to the oxidation of pyrite. There is a much narrower and lower range of δ 34S in surface water compared to the groundwater samples. With most δ 34S values less than +7‰, none of the high values measured in the boreholes were noted in the surface water, hyporheic zone or soil leachate samples, except for two samples in the hyporheic zone of Woodham Burn with δ 34S +36.3‰ and +13.4‰, values taken as further evidence of the sulphate reduction during the 2018 summer indicated by the hydrochemistry. Recommendations for future work, building upon these findings, are suggested

Accounting for groundwater in future city visions

City planners, urban innovators and researchers are increasingly working on ‘future city’ initiatives to investigate the physical, social and political aspects of harmonized urban living. Despite this, sustainability principles and the importance of urban groundwater are lacking in future city visions. Using London as a case study, the importance of groundwater for cities is highlighted and a range of future city interventions may impact on groundwater are reviewed. Using data from water resource plans and city planning strategies, changes in the groundwater balance which may occur as a result of city interventions are calculated for two future city scenarios: a ‘strategic’ future informed by organisational policy and an ‘aspirational’ future guided by sustainability principles. For London, under a strategic future, preferential investment in industry-scale technologies such as wastewater treatment and groundwater storage would occur. Acknowledgement that behaviour change offers the potential for a faster rate of transformation than innovation technologies is ignored. The capacity of community-led action and smart-home technologies to deliver sustainable water use under an aspirational future is evident, with a measurable impact on urban groundwater. These methods may be used to inform city interventions that consider the social context in addition to environmental constraints and business drivers

Material properties and geohazards

In engineering terms, all materials deposited as a result of glacial and periglacial processes are transported soils. Many of these deposits have engineering characteristics that differ from those of water-lain sediments. In the UK, the most extensive glacial and periglacial deposits are tills. Previously, engineering geologists have classified them geotechnically as lodgement, melt-out, flow and deformation tills, or as variants of these. However, in this book tills have been reclassified as: subglacial traction till, glaciotectonite and supraglacial mass-flow diamicton/glaciogenic debris-flow deposits (see Chapter 4, Sections 4.1–4.3). Because this classification is new, it is not possible to relate geotechnical properties and characteristics to the subdivisions of the new classification. Consequently, the domain/stratigraphic classification, recently developed by the British Geological Survey and others, has been used and their geotechnical properties and characteristics are discussed on this basis. The geotechnical properties and characteristics of the other main glacial and periglacial deposits are also discussed. For some of these (e.g. glaciolacustrine deposits, quick clays and loess), geohazards relating to the lithology and/or fabric of the deposit are discussed along with their properties. Other geohazards that do not relate to lithology and/or fabric are discussed separately as either local or regional geohazards. In some cases (e.g. glaciofluvial sands and gravels), the geotechnical properties and behaviour are similar to sediments deposited under different climatic conditions; these deposits are therefore not discussed at length. Similarly, some of the local geohazards that are found associated with glacial and periglacial deposits relate to current climatic conditions and are not discussed here. Examples include landsliding and highly compressible organic soils (peats)

QED3 theory of underdoped high temperature superconductors

Low-energy theory of d-wave quasiparticles coupled to fluctuating vortex loops that describes the loss of phase coherence in a two dimensional d-wave superconductor at T=0 is derived. The theory has the form of 2+1 dimensional quantum electrodynamics (QED3), and is proposed as an effective description of the T=0 superconductor-insulator transition in underdoped cuprates. The coupling constant ("charge") in this theory is proportional to the dual order parameter of the XY model, which is assumed to be describing the quantum fluctuations of the phase of the superconducting order parameter. The principal result is that the destruction of phase coherence in d-wave superconductors typically, and immediately, leads to antiferromagnetism. The transition can be understood in terms of the spontaneous breaking of an approximate "chiral" SU(2) symmetry, which may be discerned at low enough energies in the standard d-wave superconductor. The mechanism of the symmetry breaking is analogous to the dynamical mass generation in the QED3, with the "mass" here being proportional to staggered magnetization. Other insulating phases that break chiral symmetry include the translationally invariant "d+ip" and "d+is" insulators, and various one dimensional charge-density and spin-density waves. The theory offers an explanation for the rounded d-wave-like dispersion seen in ARPES experiments on Ca2CuO2Cl2 (F. Ronning et. al., Science 282, 2067 (1998)).Comment: Revtex, 20 pages, 5 figures; this is a much extended follow-up to the Phys. Rev. Lett. vol.88, 047006 (2002) (cond-mat/0110188); improved presentation, many additional explanations, comments, and references added, sec. IV rewritten. Final version, to appear in Phys. Rev.

Universal DNA methylation age across mammalian tissues

DATA AVAILABILITY STATEMENT : The individual-level data from the Mammalian Methylation Consortium can be accessed from several online locations. All data from the Mammalian Methylation Consortium are posted on Gene Expression Omnibus (complete dataset, GSE223748). Subsets of the datasets can also be downloaded from accession numbers GSE174758, GSE184211, GSE184213, GSE184215, GSE184216, GSE184218, GSE184220, GSE184221, GSE184224, GSE190660, GSE190661, GSE190662, GSE190663, GSE190664, GSE174544, GSE190665, GSE174767, GSE184222, GSE184223, GSE174777, GSE174778, GSE173330, GSE164127, GSE147002, GSE147003, GSE147004, GSE223943 and GSE223944. Additional details can be found in Supplementary Note 2. The mammalian data can also be downloaded from the Clock Foundation webpage: https://clockfoundation.org/MammalianMethylationConsortium. The mammalian methylation array is available through the non-profit Epigenetic Clock Development Foundation (https://clockfoundation.org/). The manifest file of the mammalian array and genome annotations of CpG sites can be found on Zenodo (10.5281/zenodo.7574747). All other data supporting the findings of this study are available from the corresponding author upon reasonable request. The chip manifest files, genome annotations of CpG sites and the software code for universal pan-mammalian clocks can be found on GitHub95 at https://github.com/shorvath/MammalianMethylationConsortium/tree/v2.0.0. The individual R code for the universal pan-mammalian clocks, EWAS analysis and functional enrichment studies can be also found in the Supplementary Code.SUPPLEMENTARY MATERIAL 1 : Supplementary Tables 1–3 and Notes 1–6.SUPPLEMENTARY MATERIAL 2 : Reporting SummarySUPPLEMENTARY MATERIAL 3 : Supplementary Data 1–14.SUPPLEMENTARY MATERIAL 4 : Supplementary Code.Aging, often considered a result of random cellular damage, can be accurately estimated using DNA methylation profiles, the foundation of pan-tissue epigenetic clocks. Here, we demonstrate the development of universal pan-mammalian clocks, using 11,754 methylation arrays from our Mammalian Methylation Consortium, which encompass 59 tissue types across 185 mammalian species. These predictive models estimate mammalian tissue age with high accuracy (r > 0.96). Age deviations correlate with human mortality risk, mouse somatotropic axis mutations and caloric restriction. We identified specific cytosines with methylation levels that change with age across numerous species. These sites, highly enriched in polycomb repressive complex 2-binding locations, are near genes implicated in mammalian development, cancer, obesity and longevity. Our findings offer new evidence suggesting that aging is evolutionarily conserved and intertwined with developmental processes across all mammals.https://www.nature.com/nataginghj2024Zoology and EntomologySDG-15:Life on lan

Hydrogeological significance of secondary terrestrial carbonate deposition in karst environments

proportion of the dissolved calcium carbonate derived from limestone dissolution. The study of such secondary deposits is important because they provide information on the palaeohydrogeology of the unsaturated zone at the time of precipitation. They also offer the potential to provide information with respect to climatic conditions through the study of stable isotopes and dating through the study of radiogenic isotopes. This chapter introduces the formational processes, depositional environments (hydrogeological, hydrogeochemical, biological and geomorphological) and post depositional history of secondary terrestrial carbonate deposits. Consideration is given to the associated research themes and techniques, in particular to the current research focus on the role of microbial communities in present day sediment-water interface processes (Pedley and Rogerson, 2010) and the implications for furthering the understanding of climate change and landscape evolution. These deposits have a world-wide distribution (Ford and Pedley, 1996; Viles and Goudie, 1990) and include speleothems, travertines, tufas, calcareous nodules, calcretes and carbonate cements, such that speleothems and tufa represent two end members of a continuum of freshwater carbonate (Pedley and Rogerson, 2010). They form in a range of climatic conditions, but are best developed in warm humid climates. Examples cited in the text include case studies from the White Peak, Derbyshire UK, which currently experiences a temperate humid climate and hosts a range of deposits as a consequence of its recent geological history. The White Peak was not subjected to glacial erosion during the most recent (Devensian, MIS 2-4) glaciation, therefore there is a potential for an extensive record of Quaternary palaeoclimatic conditions to be preserved in the secondary carbonate deposits

Hydrogeochemical observations to improve site characterisation and remediation of Frongoch Mine, Wales

This report, commissioned by the Environmental Agency, presents a review of the hydrogeochemistry of the Frongoch Mine, an abandoned metal mine 17 km south east of Aberystwyth, Ceridigion, mid Wales. The mine produced lead and zinc ore from 1798 until its closure in 1904. The abandoned mine spoils and mine adit discharges cause severe adverse impacts on the receiving watercourses, the major contaminants being Zn and Pb. The main objectives of the study were to: 1. Present EA and BGS water monitoring data collected from 2003 to 2011 to provide a basis for documenting the likely effects of future remedial actions on Zn and Pb concentrations. 2. Evaluate the effects of the stream diversion upstream of the Frongoch mine tailings area on flow, metal concentrations and loads of the waters impacted by the mine discharges. 3. Use mass balances for quantifying source loadings with particular regards to the Frongoch Stream, immediately downstream the mine waste area. 4. Constrain the hydrogeochemical framework, based on the available flow monitoring data, chemistry and rainfall data. The EA monitoring sites include the two main mine water issues, respectively, the mine water discharge at the Frongoch Adit portal (Frongoch Adit) and the tailings lagoon discharges via a culvert to the stream adjacent the area of mine spoils, referred to as the Frongoch Stream; upstream monitoring sites; surface water from the mine spoil area; and the Nant Cwmnewydion and Nant Cell, both tributaries of the Afon Ystwyth and both watercourses impacted by Frongoch Mine