scholarly journals Characterization of Groundwater with Complementary Age Tracers

2021 ◽  
Author(s):  
◽  
Monique Beyer
Keyword(s):  
Major Ions ◽  
Groundwater Age ◽  
Groundwater Resources ◽  
Cost Effective ◽  
Environmental Tracers ◽  
Application Range ◽  
Groundwater Dating ◽  
Model Components ◽  
The Many

<p>Groundwater age or residence time is the time water has resided in the subsurface since recharge. Depending on the application, this definition may or may not include travel through the unsaturated zone. The determination of groundwater age can aid understanding and characterization of groundwater resources, because it can provide information on e.g. groundwater mixing and flow, and volumes of groundwater and recharge. Groundwater age can be inferred from environmental tracers, such as SF₆ and tritium, that have a known input to groundwater and/or undergo known alteration processes in groundwater. The currently used age tracers face limitations regarding their application range and reliability. For example, some age tracers have local sources that can lead to contamination of groundwater. This contamination can result in misleading estimates of age. Other tracers have ambiguous inputs to groundwater, which can result in ambiguous age estimations. To reduce these limitations, it is now recognized that multiple tracers should be applied complementarily. There is also a need for new groundwater age tracers and/or new groundwater dating techniques to supplement the existing ones. Cost-effective and easily applicable tracers/techniques are preferred, since most established groundwater dating techniques are very costly and/or complex. Commonly measured hydrochemistry parameters , such as the concentrations of major ions and pH, have been suggested as cost-effective and easily determinable potential age tracers. To date, the use of commonly measured hydrochemistry parameters as independent age tracer has only been demonstrated for water recharged weeks to months ago relying on seasonal changes. Other studies applied commonly measured hydrochemistry complementarily to established age tracers to better constrain groundwater age and/or better understand and predict anthropogenic effects on groundwater quality. Further study is needed to assess the extent to which commonly measured hydrochemistry can be used to reduce uncertainty in tracer-inferred age as well as the extent to which commonly measured hydrochemistry can be used to extrapolate tracer-inferred age.  In addition to tracer specific limitations, quantification of uncertainty and ambiguity is not standard in age modelling. Although a few studies have attempted to quantify uncertainty in age modelling with the aid of probabilistic approaches, their methods are often relatively complex and not transferrable to the many cases with little available data. Uncertainties in the tracer’s recharge estimate and identification of appropriate model components, such as the objective function, have not been considered. Studies in other areas of hydrological modelling, where probabilistic approaches are more commonly used, have highlighted the need for careful identification of model components.</p>

scholarly journals Characterization of Groundwater with Complementary Age Tracers

2021 ◽  
Author(s):  
◽  
Monique Beyer
Keyword(s):  
Major Ions ◽  
Groundwater Age ◽  
Groundwater Resources ◽  
Cost Effective ◽  
Environmental Tracers ◽  
Application Range ◽  
Groundwater Dating ◽  
Model Components ◽  
The Many

<p>Groundwater age or residence time is the time water has resided in the subsurface since recharge. Depending on the application, this definition may or may not include travel through the unsaturated zone. The determination of groundwater age can aid understanding and characterization of groundwater resources, because it can provide information on e.g. groundwater mixing and flow, and volumes of groundwater and recharge. Groundwater age can be inferred from environmental tracers, such as SF₆ and tritium, that have a known input to groundwater and/or undergo known alteration processes in groundwater. The currently used age tracers face limitations regarding their application range and reliability. For example, some age tracers have local sources that can lead to contamination of groundwater. This contamination can result in misleading estimates of age. Other tracers have ambiguous inputs to groundwater, which can result in ambiguous age estimations. To reduce these limitations, it is now recognized that multiple tracers should be applied complementarily. There is also a need for new groundwater age tracers and/or new groundwater dating techniques to supplement the existing ones. Cost-effective and easily applicable tracers/techniques are preferred, since most established groundwater dating techniques are very costly and/or complex. Commonly measured hydrochemistry parameters , such as the concentrations of major ions and pH, have been suggested as cost-effective and easily determinable potential age tracers. To date, the use of commonly measured hydrochemistry parameters as independent age tracer has only been demonstrated for water recharged weeks to months ago relying on seasonal changes. Other studies applied commonly measured hydrochemistry complementarily to established age tracers to better constrain groundwater age and/or better understand and predict anthropogenic effects on groundwater quality. Further study is needed to assess the extent to which commonly measured hydrochemistry can be used to reduce uncertainty in tracer-inferred age as well as the extent to which commonly measured hydrochemistry can be used to extrapolate tracer-inferred age.  In addition to tracer specific limitations, quantification of uncertainty and ambiguity is not standard in age modelling. Although a few studies have attempted to quantify uncertainty in age modelling with the aid of probabilistic approaches, their methods are often relatively complex and not transferrable to the many cases with little available data. Uncertainties in the tracer’s recharge estimate and identification of appropriate model components, such as the objective function, have not been considered. Studies in other areas of hydrological modelling, where probabilistic approaches are more commonly used, have highlighted the need for careful identification of model components.</p>

scholarly journals Assessment of Halon-1301 as a groundwater age tracer

2015 ◽  
Vol 19 (6) ◽  
pp. 2775-2789 ◽  
Author(s):  
M. Beyer ◽  
R. van der Raaij ◽  
U. Morgenstern ◽  
B. Jackson
Keyword(s):  
Groundwater Age ◽  
Groundwater Resources ◽  
Water Soluble ◽  
Elevated Concentration ◽  
Environmental Tracers ◽  
Halon 1301 ◽  
Gaseous Substance ◽  
Groundwater Samples ◽  
Groundwater Dating ◽  
Age Estimates

Abstract. Groundwater dating is an important tool to assess groundwater resources in regards to their dynamics, i.e. direction and timescale of groundwater flow and recharge, contamination risks and manage remediation. To infer groundwater age information, a combination of different environmental tracers, such as tritium and SF6, are commonly used. However, ambiguous age interpretations are often faced, due to a limited set of available tracers and their individual restricted application ranges. For more robust groundwater dating multiple tracers need to be applied complementarily (or other characterisation methods need to be used to complement tracer information). It is important that additional, groundwater age tracers are found to ensure robust groundwater dating in future. We have recently suggested that Halon-1301, a water soluble and entirely anthropogenic gaseous substance, may be a promising candidate, but its behaviour in water and suitability as a groundwater age tracer had not yet been assessed in detail. In this study, we determined Halon-1301 and inferred age information in 17 New Zealand groundwater samples and various modern (river) water samples. The samples were simultaneously analysed for Halon-1301 and SF6, which allowed for identification of issues such as contamination of the water with modern air during sampling. All analysed groundwater sites had also been previously dated with tritium, CFC-12, CFC-11 and SF6, and exhibited mean residence times ranging from modern (close to 0 years) to over 100 years. The investigated groundwater samples ranged from oxic to highly anoxic. All samples with available CFC data were degraded and/or contaminated in one or both of CFC-11 and CFC-12. This allowed us to make a first attempt of assessing the conservativeness of Halon-1301 in water, in terms of presence of local sources and its sensitivity towards degradation, which could affect the suitability of Halon-1301 as groundwater age tracer. Overall we found Halon-1301 reliably inferred the mean residence time of groundwater recharged between 1980 and 2014. Where direct age comparison could be made 71% of mean age estimates for the studied groundwater sites were in agreement with ages inferred from tritium and SF6 (within an uncertainty of 1 standard deviation). The remaining (anoxic) sites showed reduced concentrations of Halon-1301 along with even further reduced concentrations of CFCs. The reason(s) for this need to be further assessed, but are likely to be caused by sorption or degradation of the compounds. Despite some groundwater samples showing evidence of contamination from industrial or agricultural sources (inferred by elevated CFC concentrations), no sample showed a significantly elevated concentration of Halon-1301, which suggests no local anthropogenic or geologic sources of Halon-1301 contamination.

scholarly journals Assessment of Halon-1301 as a groundwater age tracer

2015 ◽  
Vol 12 (1) ◽  
pp. 1397-1436
Author(s):  
M. Beyer ◽  
R. van der Raaij ◽  
U. Morgenstern ◽  
B. Jackson
Keyword(s):  
Groundwater Age ◽  
Groundwater Resources ◽  
Water Soluble ◽  
Elevated Concentration ◽  
Environmental Tracers ◽  
Halon 1301 ◽  
Gaseous Substance ◽  
Groundwater Samples ◽  
Groundwater Dating ◽  
Age Estimates

Abstract. Groundwater dating is an important tool to assess groundwater resources in regards to their dynamics, i.e. direction and time scale of groundwater flow and recharge, to assess contamination risks and manage remediation. To infer groundwater age information, a combination of different environmental tracers, such as tritium and SF6, are commonly used. However, ambiguous age interpretations are often faced, due to a limited set of available tracers and their individual restricted application ranges. For more robust groundwater dating multiple tracers need to be applied complementarily and it is vital that additional, groundwater age tracers are found to ensure robust groundwater dating in future. We recently suggested that Halon-1301, a water soluble and entirely anthropogenic gaseous substance, may be a promising candidate, but its behaviour in water and suitability as a groundwater age tracer had not yet been assessed in detail. In this study, we determine Halon-1301 and infer age information in 17 New Zealand groundwaters and various modern (river) water samples. The samples are simultaneously analysed for Halon-1301 and SF6, which allows identification of issues such as contamination of the water with modern air during sampling. Water at all analysed groundwater sites have also been previously dated with tritium, CFC-12, CFC-11 and SF6, and exhibit mean residence times ranging from modern (close to 0 years) to over 100 years. The investigated groundwater ranged from oxic to highly anoxic, and some showed evidence of CFC contamination or degradation. This allowed us to make a first attempt of assessing the conservativeness of Halon-1301 in water, in terms of presence of local sources and its sensitivity towards degradation etc., which could affect the suitability of Halon-1301 as groundwater age tracer. Overall we found Halon-1301 reliably inferred the mean residence time of groundwater recharged between 1980 and 2014. Where direct age comparison could be made 71% of mean age estimates for the studied groundwater sites were in agreement with ages inferred from tritium and SF6 (within ± 2 years). The remaining (anoxic) sites showed reduced concentrations of Halon-1301 along with even further reduced concentrations of CFCs. The reason(s) for this need to be further assessed, but are likely to be caused by sorption or degradation of the compounds. Despite some groundwater samples showing evidence of contamination from industrial or agricultural sources via elevated CFC concentrations, no sample indicated significantly elevated concentration of Halon-1301, which may indicate a lack of local anthropogenic or geologic sources of Halon-1301 contamination.

Use of multiple tracers and groundwater flow modelling for the estimation of groundwater travel times to water supply wells, vulnerability assessments and improved management of well fields

2020 ◽  
Author(s):  
Klaus Hinsby ◽  
Roland Purtschert ◽  
Stéphanie Musy ◽  
Jürgen Sültenfuss ◽  
David Wachs ◽  
...  
Keyword(s):  
Water Supply ◽  
Travel Time ◽  
Emerging Contaminants ◽  
Groundwater Modeling ◽  
Groundwater Resources ◽  
Environmental Tracers ◽  
Monitoring Wells ◽  
Groundwater Flow Modelling ◽  
Groundwater Dating ◽  
Water Companies

&lt;p&gt;Groundwater dating and travel time distributions are important tools and data for assessment of the vulnerability of water supply wells towards pollution from the surface. Here we present selected results from more than 30 water supply and monitoring wells from major Danish water companies. The wells were recently sampled and investigated using multiple environmental tracers including &lt;sup&gt;85&lt;/sup&gt;Kr, &lt;sup&gt;39&lt;/sup&gt;Ar, &lt;sup&gt;3&lt;/sup&gt;H/&lt;sup&gt;3&lt;/sup&gt;He, &lt;sup&gt;14&lt;/sup&gt;C, SF&lt;sub&gt;6&lt;/sub&gt;, CFCs and noble gases and different groundwater modeling techniques. The results demonstrate the value of groundwater dating and travel time estimations for the assessment of the history and fate of contaminants in the subsurface. This information is crucial for the assessment of the efficiency of measures to mitigate pollution of groundwater by harmful substances such as pesticides, nitrate and a large range of emerging contaminants. We demonstrate how groundwater ages and travel time distributions can be used to assess the vulnerability or susceptibility of water supply wells towards pollution, and how level specific sampling in long well screens can provide additional important information for assessment of the vulnerability of deep and shallow parts of a water supply well. Potential applications of the estimated travel time distributions include 1) improved management of well fields 2) development of pumping strategies and well screens minimizing the risk of pollution of drinking water wells, and 3) assessment of the adequacy of regulations established by authorities to protect valuable groundwater resources against pollution. &amp;#160;&amp;#160;&lt;/p&gt;

scholarly journals Characterization of Polymer Powders and Effects of Powder Reuse in Selective Laser Sintering

2021 ◽  
Vol 33 (3) ◽  
pp. 658-664
Author(s):  
H. Chiririwa
Keyword(s):  
Additive Manufacturing ◽  
Selective Laser Sintering ◽  
Polymeric Materials ◽  
Cost Effective ◽  
Laser Sintering ◽  
Polyamide 12 ◽  
Extensive Range ◽  
The Many ◽  
Selection Of

Selective laser sintering (SLS) had been recognized as production expertise (additive manufacturing). The complication restricting the use of SLS in additive manufacturing in an extensive range of industrial scope is the limited selection of usable polymers as it is only limited to polyamide 12. Other polymeric materials such as polypropylene and polyethylene are needed to establish pristine market avenues in industry. In selective laser sintering, the powder is reused in consecutive cycles of the route for the reason that it is sustainable and cost effective. Characterization procedures, including the many available techniques has been proposed to determine changes in chemical microstructures, morphology along with flowability. Subtle disimilarities linking virgin and used powder have been identified through characterization.

Monitoring of Petroleum-Related Environmental Contamination Using Fluorescence Fingerprinting

2006 ◽  
Vol 1 (2) ◽  
Author(s):  
P. Literathy ◽  
M. Quinn
Keyword(s):  
Environmental Contamination ◽  
Statistical Evaluation ◽  
Oil Pollution ◽  
Emission Spectra ◽  
Cost Effective ◽  
Petroleum Products ◽  
Danube River ◽  
Aromatic Components ◽  
Analytical Approaches

Petroleum and its refined products are considered the most complex contaminants frequently impacting the environment in significant quantities. They have heterogeneous chemical composition and alterations occur during environmental weathering. No single analytical method exists to characterize the petroleum-related environmental contamination. For monitoring, the analytical approaches include gravimetric, spectrometric and chromatographic methods having significant differences in their selectivity, sensitivity and cost-effectiveness. Recording fluorescence fingerprints of the cyclohexane extracts of the water, suspended solids, sediment or soil samples and applying appropriate statistical evaluation (e.g. by correlating the concatenated emission spectra of the fingerprints of the samples with arbitrary standards (e.g. petroleum products)), provides a powerful, cost-effective analytical tool for characterization of the type of oil pollution and detecting the most harmful aromatic components of the petroleum contaminated matrix. For monitoring purposes, the level of the contamination can be expressed as the equivalent concentration of an appropriate characteristic standard, based on the fluorescence intensities at the relevant characteristic wavelengths. These procedures are demonstrated in the monitoring of petroleum-related pollution in the water and suspended sediment in the Danube river basin

Green Synthesis and Spectroscopic Studies of Ag-rGO Nanocomposites for Highly Selective Mercury (II) Sensing

2018 ◽  
Vol 9 (1) ◽  
pp. 101-108 ◽  
Author(s):  
Shubhangi J. Mane-Gavade ◽  
Sandip R. Sabale ◽  
Xiao-Ying Yu ◽  
Gurunath H. Nikam ◽  
Bhaskar V. Tamhankar
Keyword(s):  
Green Synthesis ◽  
Color Change ◽  
Limit Of Detection ◽  
Aqueous Media ◽  
Suitable Condition ◽  
Cost Effective ◽  
Spectroscopic Studies ◽  
Calibration Plot ◽  
First Time

Introduction: Herein we report the green synthesis and characterization of silverreduced graphene oxide nanocomposites (Ag-rGO) using Acacia nilotica gum for the first time. Experimental: We demonstrate the Hg2+ ions sensing ability of the Ag-rGO nanocomposites form aqueous medium. The developed colorimetric sensor method is simple, fast and selective for the detection of Hg2+ ions in aqueous media in presence of other associated ions. A significant color change was noticed with naked eye upon Hg2+ addition. The color change was not observed for cations including Sr2+, Ni2+, Cd2+, Pb2+, Mg2+, Ca2+, Fe2+, Ba2+ and Mn2+indicating that only Hg2+ shows a strong interaction with Ag-rGO nanocomposites. Under the most suitable condition, the calibration plot (A0-A) against concentration of Hg2+ was linear in the range of 0.1-1.0 ppm with a correlation coefficient (R2) value 0.9998. Results & Conclusion The concentration of Hg2+ was quantitatively determined with the Limit of Detection (LOD) of 0.85 ppm. Also, this method shows excellent selectivity towards Hg2+ over nine other cations tested. Moreover, the method offers a new cost effective, rapid and simple approach for the detection of Hg2+ in water samples.

Theology in the Church of England

2017 ◽  
Author(s):  
B. W. Young
Keyword(s):  
Eighteenth Century ◽  
Church Of England ◽  
Ecclesiastical History ◽  
International Reputation ◽  
History Of ◽  
Joseph Butler ◽  
Anglican Theology ◽  
The Many ◽  
The Church

The dismissive characterization of Anglican divinity between 1688 and 1800 as defensive and rationalistic, made by Mark Pattison and Leslie Stephen, has proved more enduring than most other aspects of a Victorian critique of the eighteenth-century Church of England. By directly addressing the analytical narratives offered by Pattison and Stephen, this chapter offers a comprehensive re-evaluation of this neglected period in the history of English theology. The chapter explores the many contributions to patristic study, ecclesiastical history, and doctrinal controversy made by theologians with a once deservedly international reputation: William Cave, Richard Bentley, William Law, William Warburton, Joseph Butler, George Berkeley, and William Paley were vitalizing influences on Anglican theology, all of whom were systematically depreciated by their agnostic Victorian successors. This chapter offers a revisionist account of the many achievements in eighteenth-century Anglican divinity.

The development of body and organ shape

BMC Zoology ◽  
2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Ansa E. Cobham ◽  
Christen K. Mirth
Keyword(s):  
Relative Position ◽  
Body Shape ◽  
Single Cells ◽  
The Other ◽  
Geometric Features ◽  
Main Text ◽  
Size Characterization ◽  
Organ Shape ◽  
The Many

Abstract Background Organisms show an incredibly diverse array of body and organ shapes that are both unique to their taxon and important for adapting to their environment. Achieving these specific shapes involves coordinating the many processes that transform single cells into complex organs, and regulating their growth so that they can function within a fully-formed body. Main text Conceptually, body and organ shape can be separated in two categories, although in practice these categories need not be mutually exclusive. Body shape results from the extent to which organs, or parts of organs, grow relative to each other. The patterns of relative organ size are characterized using allometry. Organ shape, on the other hand, is defined as the geometric features of an organ’s component parts excluding its size. Characterization of organ shape is frequently described by the relative position of homologous features, known as landmarks, distributed throughout the organ. These descriptions fall into the domain of geometric morphometrics. Conclusion In this review, we discuss the methods of characterizing body and organ shape, the developmental programs thought to underlie each, highlight when and how the mechanisms regulating body and organ shape might overlap, and provide our perspective on future avenues of research.

scholarly journals Physicochemical evolution and evaluation of groundwater quality in Mougheul area (Southwest of Algeria)

2021 ◽  
Vol 11 (2) ◽  
Author(s):  
Saliha Mebarki ◽  
Benali Kharroubi ◽  
Mohammed Amin Kendouci
Keyword(s):  
Physicochemical Parameters ◽  
Calcium Sulfate ◽  
Major Ions ◽  
Groundwater Resources ◽  
Triangular Diagram ◽  
Wilcox Diagram ◽  
Calcium And Magnesium ◽  
Increasing Demand ◽  
Pressure On Water Resources

AbstractIn arid areas, the pressure on water resources and in particular on groundwater resources is on the rise, mainly due to increasing demand and the deterioration of water quality. In this context, the present work aims to follow the annual evolution, between 2009 and 2019 of the physicochemical parameters, and to evaluate the quality of groundwater of the region of Mougheul, by determining the data of pH, TDS, conductivity and the concentrations of major ions ( Ca+2, Mg+2, Na+, K+, Cl−, HCO3−, SO4−2, NO3−) of 07 water points. The results revealed that all the levels of the physicochemical parameters do not exceed the WHO potability standards, except high values were observed at the level of well W6 which exceeds the limits recommended by the WHO (50 mg /l). The diagram of Schöeller and Berkaloff shows that the groundwater has the bicarbonate magnesium facies. The representation of the data on the Piper triangular diagram shows that W6 has the facies chlorinated and calcium sulfate and magnesium and the other water points have the facies bicarbonate calcium and magnesium. SAR values show that the groundwater of Mougheul is excellent for irrigation. The classification according to the Wilcox diagram shows that the groundwater of Mougheul in general is good quality, but the well of W6 water is suitable for irrigation and requires monitoring the evolution of salinity.

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