Regional Isotopic Signatures of Groundwater in Croatia

Tracer methods are useful for investigating groundwater travel times and recharge rates and analysing impacts on groundwater quality. The most frequently used tracers are stable isotopes and tritium. Stable isotopes of oxygen (δ18O) and hydrogen (δ2H) are mainly used as indicators of the recharge condition. Tritium (3H) is used to estimate an approximate mean groundwater age. This paper presents the results of an analysis of stable isotope data and tritium activity in Croatian groundwater samples that were collected between 1997 and 2014 at approximately 100 sites. The composition of the stable isotopes of groundwater in Croatia originates from recent precipitation and is described using two regional groundwater lines. One of them is applied to groundwater accumulated in the aquifers in the Pannonian part of Croatia and the other is for groundwater accumulated in the Dinaric karst of Croatia. The isotope content shows that the studied groundwater is mainly modern water. A mix of sub-modern and modern water is mostly accumulated in semi-confined porous aquifers in northern Croatia, deep carbonate aquifers, and (sub)thermal springs.

Download Full-text

Renewed thinking on groundwater age

10.5194/egusphere-egu21-3479 ◽

2021 ◽

Author(s):

Grant Ferguson ◽

Mark Cuthbert ◽

Kevin Befus ◽

Tom Gleeson ◽

Chandler Noyes ◽

...

Keyword(s):

Environmental Flows ◽

Numerical Models ◽

Groundwater Age ◽

Holistic Approach ◽

Water Levels ◽

Residence Times ◽

Groundwater Sustainability ◽

Long Time ◽

Mean Residence Times ◽

Recharge Rates

Groundwater age and mean residence times have been invoked as measures of groundwater sustainability, with the idea that old or "fossil" groundwater is non-renewable. This idea appears to come from the link between groundwater age and background recharge rates, which are also of questionable use in assessing the sustainability of groundwater withdrawals. The use of groundwater age to assess renewability is further complicated by its relationship with flow system geometry. Young groundwaters near recharge areas are not inherently more renewable than older groundwaters down gradient. Similarly, there is no reason to preferentially use groundwater from smaller aquifers, which will have smaller mean residence times than larger aquifers for the same recharge rate. In some cases, groundwater ages may provide some information where groundwater recharge rates were much higher in the past and systems are no longer being recharged. However, there are few examples where the relationship between depletion and changes in recharge over long time periods has been rigorously explored. Groundwater age measurements can provide insights into the functioning of groundwater flow systems and calibration targets for numerical models and we advocate for their continued use, but they are not a metric of sustainable development. Simple metrics to assess groundwater sustainability remain elusive and a more holistic approach is warranted to maintain water levels and environmental flows.

Download Full-text

Distribution in natural abundances of stable isotopes of nitrate and retained sludge in a nitrifying bioreactor: Drastic changes in isotopic signatures

The Science of The Total Environment ◽

10.1016/j.scitotenv.2019.134438 ◽

2020 ◽

Vol 705 ◽

pp. 134438 ◽

Cited By ~ 1

Author(s):

Takashi Onodera ◽

Gen Kanaya ◽

Ayato Kohzu ◽

Kazuaki Syutsubo

Keyword(s):

Stable Isotopes ◽

Isotopic Signatures

Download Full-text

Estimating the Isotopic Altitude Gradient for Hydrogeological Studies in Mountainous Areas: Are the Low-Yield Springs Suitable? Insights from the Northern Apennines of Italy

Water ◽

10.3390/w11091764 ◽

2019 ◽

Vol 11 (9) ◽

pp. 1764 ◽

Cited By ~ 1

Author(s):

Tazioli ◽

Cervi ◽

Doveri ◽

Mussi ◽

Deiana ◽

...

Keyword(s):

Stable Isotopes ◽

Tyrrhenian Sea ◽

Precipitation Regime ◽

Altitude Effect ◽

Air Masses ◽

Isotopic Signatures ◽

Stable Isotopic ◽

Windward Slope ◽

Hydrogeological Studies ◽

Stable Isotopes Of Water

Several prior studies investigated the use of stable isotopes of water in hydrogeological applications, most on a local scale and often involving the isotopic gradient (evaluated by exploiting the so-called altitude effect), calculated on the basis of rainwater isotopes. A few times, this gradient has been obtained using the stable isotopic contents of low-yield springs in a limited time series. Despite the fact that this method has been recognized by the hydrogeological community, marked differences have been observed with respect to the mean stable isotopes content of groundwater and rainwater. The present investigation compares the stable isotopic signatures of 23 low-yield springs discharging along two transects from the Tyrrhenian sea to the Po Plain of Italy, evaluates the different isotopic gradients and assesses their distribution in relation to some climatic and topographic conditions. Stable isotopes of water show that groundwater in the study area is recharged by precipitation and that the precipitation regime in the eastern portion of the study area is strongly controlled by a shadow effect caused by the Alps chain on the air masses from central Europe. Stable isotopes (in particular the δ18O and deuterium excess (d-excess) contents together with the obtained isotopic gradients) allow us to identify in the study area an opposite oriented orographic effect and a different provenance of the air masses. When the windward slope is located on the Tyrrhenian side, the precipitation shows a predominant oceanic origin; when the windward slope moves to the Adriatic side, the precipitation is characterized by a continental origin. The main results of this study confirm the usefulness of low-yield springs and the need for a highly detailed survey-scale hydrological investigation in the mountainous context.

Download Full-text

Assessment of Halon-1301 as a groundwater age tracer

Hydrology and Earth System Sciences ◽

10.5194/hess-19-2775-2015 ◽

2015 ◽

Vol 19 (6) ◽

pp. 2775-2789 ◽

Cited By ~ 5

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.

Download Full-text

Diet and status in Birka: stable isotopes and grave goods compared

Antiquity ◽

10.1017/s0003598x00096939 ◽

2008 ◽

Vol 82 (316) ◽

pp. 446-461 ◽

Cited By ~ 50

Author(s):

Anna Linderholm ◽

Charlotte Hedenstierna Jonson ◽

Olle Svensk ◽

Kerstin Lidén

Keyword(s):

Stable Isotopes ◽

Isotopic Signatures ◽

The Status ◽

Viking Period ◽

Grave Goods

In this paper the authors investigate isotopic signatures of burials from the famous Viking period cemetery at Birka in Sweden, comparing their results on diet with the status and identities of individuals as interpreted from grave goods. These first observations offer a number of promising correlations, for example the shared diet of a group of women associated with trade, and a marine emphasis among men buried with weapons.

Download Full-text

Mapping river recharge rates with stable isotopes and tritium-helium groundwater ages

10.5194/egusphere-egu21-6887 ◽

2021 ◽

Author(s):

Ate Visser ◽

Laura Foglia ◽

Helen Dahlke ◽

Amelia Vankeuren ◽

Maribeth Kniffin ◽

...

Keyword(s):

Stable Isotopes ◽

Groundwater Management ◽

River Water ◽

Central Valley ◽

Shallow Aquifer ◽

River Bank ◽

Cosumnes River ◽

Water Recharge ◽

Groundwater Basin ◽

Recharge Rates

While climate change will challenge the future of California&#8217;s water resources, groundwater can buffer variability in precipitation and streamflow, if managed sustainably. Enhanced river recharge is an important tool to reach sustainable groundwater management in the California Central Valley (USA). Understanding and predicting recharge rates of river water, either natural river bank infiltration or managed aquifer recharge (MAR) during floods (Flood-MAR) or on agricultural land (Ag-MAR) is essential to evaluate the sustainability of groundwater management plans. Groundwater ages, combined with other isotopic and noble gas evidence, can elucidate surface water-groundwater interactions and support river recharge rates calculations over longer time periods.Our study is focused on the recharge from the Cosumnes River in the California Central Valley. The Cosumnes River forms the boundary between the Sacramento Valley groundwater basin to the north and the San Joaquin Valley groundwater basin to the south. For this study, 28 new samples were collected for the analysis of 3H/3He age, noble gases, and stable isotopes. 25 additional samples from the California Waterboards Groundwater Ambient Monitoring and Assessment (GAMA) Shallow Aquifer Assessment program were included, which were collected and analyzed by the USGS California Water Science Center in 2017.We find that 28% of groundwater in the San Joaquin &#8211; Cosumnes groundwater subbasin originated as river water recharge, based on the interpolated mean &#948;18O (7.7 &#8240; ), compared with river water (-9 &#8240;) and local precipitation recharge (-7 &#8240;) end-members. River water is a source of modern recharge, resulting in high tritium concentrations close to the Cosumnes River. In contrast, ambient groundwater from local precipitation recharge is predominantly pre-modern or fossil, containing less than 1 pCi/L tritium. Combining groundwater ages with the distance to the river, aquifer thickness, and porosity, estimates of river water recharge rate vary between 0.02 km3/yr and 0.035 km3/yr. These quantitative estimates of river water recharge will constrain the numerical groundwater flow model for this basin and aid groundwater managers in developing sustainability plans to balance groundwater pumping with recharge rates.

Download Full-text

Hydrogeology and Hydrogeochemistry of the Lauria Mountains Northern Sector Groundwater Resources (Basilicata, Italy)

Geofluids ◽

10.1155/2019/7039165 ◽

2019 ◽

Vol 2019 ◽

pp. 1-16 ◽

Cited By ~ 2

Author(s):

Filomena Canora ◽

Giovanna Rizzo ◽

Simona Panariello ◽

Francesco Sdao

Keyword(s):

Stable Isotopes ◽

Major Ions ◽

Groundwater Resources ◽

Quality Parameters ◽

Standard Test ◽

Chemical Compositions ◽

Test Procedures ◽

Groundwater Samples ◽

Chemical Content ◽

Northern Sector

In this study, the hydrogeological characterization of the northern sector of the Lauria Mounts carbonate hydrostructure (southern Apennines, Basilicata region) has been carried out and the hydrochemical properties of different collected groundwater samples have been characterized. Several normal springs drain the hydrostructure, some of them characterized by high annual mean discharges. Groundwater samples were collected from different springs; many parameters such as pH, electrical conductivity, and total dissolved solids have been measured, and major (cations and anions) elements and stable isotopes have been analysed following standard test procedures. Other chemical characteristics were derived from the analysed quality parameters. The results elucidate that the main hydrogeochemical processes control the chemical content and assess the quality of the groundwater within the hydrostructure. The analyses highlight that the chemical compositions of groundwater are strongly influenced by the lithology, especially limestones and dolomitic limestones; they explain and confirm the hydrogeological setting of the system. The groundwater system displays light different geochemical signatures. The processes contributing to the concentrations of major ions depend primarily on carbonate dissolution. The analysis, in all studied groundwater samples, shows that the facies groundwater type is Ca–HCO3, bicarbonate is the dominant anion, and calcium is the dominant cation with appreciable magnesium concentrations. To identify the aquifer’s recharge areas, the environmental stable isotopes oxygen and hydrogen, deuterium, and 18O were analysed. The unaltered δ18O and δD signatures for the groundwater of the major springs allows identifying the recharge area of these emergencies at elevations ranging from 900 m to 1000 m (a.s.l.), pointing out the presence of deeper flow regime feeding of these springs. The groundwater sample isotopic characteristics of D and 18O suggest that most of the groundwater is recharged directly by infiltration in a high-permeability medium.

Download Full-text

Assessing the residence time of water in volcanic lakes of north Cameroon using bomb-36Cl and stable isotopes

10.5194/egusphere-egu21-9821 ◽

2021 ◽

Author(s):

Souleyman Abba ◽

Bruno Hamelin ◽

Pierre Deschamps ◽

Yannick Garcin ◽

David Badoga ◽

...

Keyword(s):

Stable Isotopes ◽

Residence Time ◽

Regional Scale ◽

Central Africa ◽

Transient State ◽

Major Elements ◽

Lake Chad ◽

Volcanic Lakes ◽

Stable Isotopes Of Water ◽

Recharge Rates

The Cameroon Volcanic Line (CVL) in Central Africa hosts numerous volcanic lakes. While Nyos and Monoun lakes in western Cameroon were well studied following the catastrophic release of CO2 that occurred in 1980s, other volcanic lakes such as those of the Adamaoua Plateau remain less documented. Although some of these (Mbalang and Tizon) have been investigated through their sedimentary archives in order to reconstruct past-environments, the functioning of these hydro-systems located in the northern part of the CVL is not well constrained. Here, we characterize the hydrological functioning of five volcanic lakes by coupling classical hydrology methods and isotope tracers. Specifically, we assess water residence time in these lakes using radioactive (36Cl) and stable isotopes of water.36Cl is a cosmogenic isotope of chlorine produced naturally in the stratosphere by spallation of 40Ar induced by cosmic-rays and has been massively injected into the atmosphere by nuclear tests during the 1950s. This pulse of bomb-36Cl can thus be used as a tracer to estimate recharge rates in the unsaturated zone and to constrain water transit times at a regional scale. While water stable isotopes have been widely used to establish lakes hydrological balance in Sahelian regions, only a few studies have been reported to date using 36Cl for the same purpose in tropical areas.In this study, together with major elements and stable isotopes, we analyzed 36Cl contents in water from lakes Mbalang, Tabere, Tizon, Gegouba and Baledjam around Ngaoundere, to assess residence time in these lacustrine systems. 36Cl/Cl ratios range from 1400.10-15 to 2800.10-15 at/at and are significantly higher than the natural baseline as assessed by data obtained in local groundwater or at a larger scale in the Lake Chad Basin (36Cl/Cl ~200.10-15 at/at, see Bouchez et al., Scientific Reports, 2019). These 36Cl/Cl ratios above the natural baseline are clearly tagged with the bomb-36Cl footprint. We will illustrate at the meeting how a simple transient-state one-box model can be used to explain why these lakes have different 36Cl/Cl ratios, and how these results can help to constrain the E/I ratios of the lakes, and be compared with their hydrological characteristics and stable isotopes signatures.

Download Full-text

The age, distribution, and geochemical characteristics of groundwater in the Ordovician limestone aquifer in the Huaibei coalfield, China

Water Practice & Technology ◽

10.2166/wpt.2017.042 ◽

2017 ◽

Vol 12 (2) ◽

pp. 354-362

Author(s):

Song Chen ◽

Herong Gui

Keyword(s):

Major Ions ◽

Groundwater Age ◽

Age Distribution ◽

Mean Values ◽

Limestone Aquifer ◽

Ordovician Limestone ◽

Groundwater Samples ◽

Huaibei Coalfield ◽

Mining Districts ◽

Δd And Δ18o

In this study, we collected 22 groundwater samples and supporting measurements from different coal-mining districts in the Huaibei coalfield to examine the age, hydro-chemical characteristics, and evolution of groundwater in the Ordovician limestone aquifer (OA). We determined the groundwater concentrations of major ions, stable isotopes (hydrogen and oxygen) and a radio isotope (14C). All the samples were alkaline in nature, and had pH values between 7.10 and 10.80. The total dissolved solids (TDS) contents varied from 119 to 2,443 mg/l. The concentrations of δD and δ18O in groundwater varied from −64.32‰ to −42.76‰, and from −8.62‰ to −5.40‰, with mean values of −56.38‰ and −7.62‰, respectively. The groundwater at OA is recharged by rainfall or surface water, and, because of either the long residence time or runoff into the aquifer, is influenced by water-rock interactions. The age of the groundwater in the OA ranged from 2,660a to 10,040a, and the groundwaters were youngest and oldest in the Renlou and Yangzhuang coal mines, respectively. Contour diagrams of TDS in groundwater, the groundwater age, and the spatial distribution of the water types indicated that the Renlou and Yangzhuang mines were the recharge and discharge areas, respectively.

Download Full-text

Diet of the pulmonate gastropod Onchidella nigricans in the intertidal rocky shore, New Zealand

Animal Biology ◽

10.1163/157075609x437736 ◽

2009 ◽

Vol 59 (2) ◽

pp. 231-240 ◽

Cited By ~ 1

Author(s):

Andrea Alfaro

Keyword(s):

Stable Isotopes ◽

New Zealand ◽

Algal Species ◽

Rocky Intertidal ◽

Coralline Algae ◽

Gut Contents ◽

Bare Rock ◽

Generalist Herbivore ◽

Δ13c And Δ15n ◽

Isotopic Signatures

AbstractGut content analyses and stable isotopes (δ13C and δ15N) were used to investigate the food consumption and assimilation of the pulmonate, Onchidella nigricans, within a rocky intertidal platform at Waiwera, northern New Zealand. Analyses of gut contents indicate that this species is a generalist herbivore, which may consume a variety of micro- and macro-algae, although small zooplankton may be ingested, when present. Gut contents of individuals collected from different intertidal habitats (bare rock, Hormosira banksii, green filaments, and coralline algae) reflected the dominant algal species within each habitat, suggesting that food availability does not restrict the grazer's distribution across its range. The radular morphology and small size of this gastropod also support the notion that O. nigricans is a non-selective microphagous feeder. However, stable isotopes on O. nigricans from the four habitats and the dominant algal food types indicate a strong assimilation preference for microalgae. The δ13C values (-15 to -13‰) of O. nigricans were consistent with signatures for intertidal grazers, but δ15N values (8 to 9‰) were relatively high, which may indicate the presence of bacteria and microfaunal detritus in the diet. Clusters of isotopic signatures of individuals from different habitats suggest feeding preferences, which also may be attributed to differences in detrital and bacterial consumption. This study illustrates the importance of using parallel techniques in diet studies.

Download Full-text