Isotopic characteristics of meteoric waters in the Belgrade region

Abstract

The stable isotope composition of hydrogen (δ²H) and oxygen (δ¹⁸O) in monthly precipitation and river water (Sava River and Danube) samples in the Belgrade area gathered between 1992 and 2005 are determined. The local meteoric water line δ²H=7.8 (±0.2) δ¹⁸O+7.3(±1.6) (r ²=0.98, n=60, σ=0.52) for the whole period of observation is close to the global meteoric water line. The amount-weighted mean δ²H and δ¹⁸O values of precipitation were?65±27 ‰ and?9.4±3.4 ‰, respectively. Good correlation between δ¹⁸O values (r>rsim0.67) and ambient temperature and relative humidity was obtained. Stream-water data ranged from?94 to?60 ‰ for δ²H and from?11.0 to ～5.7 ‰ for δ¹⁸O with highly statistically significant difference (p>0.01) between the Sava River and the Danube. In addition, the isotopic compositions of local precipitation and adjacent river water at monitoring sites were compared. Obtained data will give an opportunity to improve the knowledge of mixing stream water and local groundwater, and assessment of potential groundwater risks and pressures in the Belgrade basin.     

Seasonal variation of oxygen-18 in precipitation and surface water of the Poyang Lake Basin,China

Based on the monthly δ¹⁸O value measured over a hydrology period in precipitation, runoff of five tributaries and the main lake of the Poyang Lake Basin, combined with hydrological and meteorological data, the characteristics of δ¹⁸O in precipitation (δ¹⁸O_PPT) and runoff (δ¹⁸O_SUR) are discussed. The δ¹⁸O_PPT and δ¹⁸O_SUR values range from?2.75 to?14.12 ‰ (annual mean value=?7.13 ‰ ) and from?2.30 to?8.56 ‰, respectively. The seasonal variation of δ¹⁸O_PPT is controlled by the air mass circulation in this region, which is dominated by the Asian summer monsoon and the Siberian High during winter. The correlation between the wet seasonal averages of δ¹⁸O_SUR in runoff of the rivers and δ¹⁸O_PPT of precipitation at the corresponding stations shows that in the Poyang Lake catchment area the river water consists of 23% direct runoff (precipitation) and 77% base flow (shallow groundwater). This high proportion of groundwater in the river runoff points to the prevalence of wetland conditions in the Poyang Lake catchment during rainy season. Considering the oxygen isotopic composition of the main body of Poyang Lake, no isotopic enrichment relative to river inflow was found during the rainy season with maximum expansion of the lake. Thus, evaporation causing isotopic enrichment is a minor component of the lake water balance in the rainy period. During dry season, a slight isotopic enrichment has been observed, which suggests a certain evaporative loss of lake water in that period.     

Isotopic Assessment of Sources and Processes Affecting Sulfate and Nitrate in Surface Water and Groundwater of Luxembourg

Abstract

Surface water and deep and shallow groundwater samples were taken from selected parts of the Grand-Duchy of Luxembourg to determine the isotopic composition of nitrate and sulfate, in order to identify sources and/or processes affecting these solutes. Deep groundwater had sulfate concentrations between 20 and 40mg/L, δ³⁴S_sulfate values between ?3.0 and ?20.0‰, and δ¹⁸O_sulfate values between +1.5 and +5.0‰ nitrate was characterized by concentrations varying between <0.5 and 10mg/L, δ¹⁵N_nitrate values of ～?0.5‰, and δ¹⁸O_nitrate values ～+3.0‰. In the shallow groundwater, sulfate concentrations ranged from 25 to 30mg/L, δ³⁴S_sulfate values from ?20.0 to +4.5‰, and δ¹⁸O_sulfate values from ～+0.5 to +4.5‰ nitrate concentrations varied between ～10 and 75mg/L, δ¹⁵N_nitrate values between +2.5 and +10.0‰, and δ¹⁸O_nitrate values between +1.0 and +3.0‰. In surface water, sulfate concentrations ranged from 10 to 210mg/L, δ³⁴S_sulfate values varied between ?9.3 and +10.9‰, and δ¹⁸O_sulfate values between +3.0 and +10.7‰ were observed. Nitrate concentrations ranged from 10 to 40mg/L, δ¹⁵N_nitrate values from +6.5 to +12.0‰, and δ¹⁸O_nitrate values from ?0.4 to +4.0‰. Based on these data, three sulfate sources were identified controlling the riverine sulfate load. These are soil sulfate, dissolution of evaporites, and oxidation of reduced S minerals in the bedrock. Both groundwater types were predominantly influenced by sulfate from the two latter lithogenic S sources. The deep groundwater and a couple shallow groundwater samples had nitrate derived mainly from soil nitrification. All other sampling sites were influenced by nitrate originating from sewage and/or manure. A decrease in nitrate concentration observed along one of the rivers was attributed to denitrification. It appears that sulfate within Luxembourg's aquatic ecosystem is mainly of lithogenic origin, whereas nitrate is often derived from anthropogenic activities.     

Application of stable isotopes and hydrochemical analysis in groundwater aquifers of Argolis Peninsula (Greece)

The present study examines the isotopic and hydrochemical composition of 18 inland spring waters and 3 coastal karstic spring waters, covering the period between October 2005 and March 2008. The stable isotopes (¹⁸O, ²H) processing has revealed the absence of significant evaporation phenomena and that the origin of fresh water samples is meteoric. Using ¹⁸O values in rainfall waters, an average line of isotopic depletion with altitude has been constructed, extracting a rate of?0.45‰/100 m as typical for the study area. Furthermore, the mean altitude of recharge of the springs has been estimated by plotting the groundwater sampling points on a δ¹⁸O versus altitude diagram. Hydrochemistry results have shown that the dissolution of carbonate, flysch and ophiolitic formations defines the hydrochemical characteristics of groundwater. Moreover, seawater intrusion in the coastal area is significantly high, causing the water in the three karstic springs to be brackish.     

Groundwater of the Crimean peninsula: a first systematic study using stable isotopes

ABSTRACT

Karst springs in the Main Range of the Crimean Mountains and the Crimean Piedmont show a restricted range of values (δ¹⁸O?=?–10.5 to –8.0 ‰, δ²H?=?–72 to –58 ‰), somewhat more negative than the weighted mean of meteoric precipitation. This suggests preferential recharge at higher elevations during winter months. Groundwater tapped by boreholes splits in three groups. A first group has isotopic properties similar to those of the springs. The second group shows significantly lower values (δ¹⁸O?=?–13.3 to –12.0 ‰, δ²H?=?–95 to –82 ‰), suggesting recharge during colder Pleistocene times. The third group has high isotope values (δ¹⁸O?=?–2.5 to +1.0 ‰, δ²H?=?–24 to –22 ‰); the data points are shifted to the right of the Local Meteoric Water Line, suggesting water–rock exchange processes in the aquifer. These boreholes are located in the Crimean Plains and discharge mineralized (ca. 25 g L^?1) thermal (65°C) water from a depth of 1600–1800 m. Groundwater associated with mud volcanoes on the Kerch peninsula have distinct isotope characteristics (δ¹⁸O?=?–1.6 to +9.4 ‰, δ²H?=?–30 to –18 ‰). Restricted δ²H variability along with variable and high δ¹⁸O values suggest water–rock interactions at temperatures exceeding 95 °C.     

Spatiotemporal patterns of stable isotopes and hydrochemistry in springs and river flow of the upper Karkheh River Basin,Iran

Karst springs of the Zagros Mountains contribute a significant amount to agricultural and human water demands of western and south-western Iran. For an adequate management of available water resources in semi-arid and arid regions, sufficient hydrological monitoring is needed, and hydro-chemical and isotope hydrological data provide important additional information. About 350 water samples were collected from precipitation, river water, and karst springs of the upper part of the Karkheh River Basin (20,895 km²) located between 33°35^′ and 34°55^′ North and 46°22^′ and 49°10^′ East with elevations ranging from 928 to 3563 m above sea level. Sampling was conducted in monthly time resolution from August 2011 to July 2012. All samples were analysed for hydro-chemical parameters (pH, electrical conductivity, and major ions) and stable isotopes (deuterium, oxygen-18). Isotope values of precipitation indicate a local meteoric water line (Zagros MWL δ²H=6.8 δ¹⁸O+10.1; R²=0.99) situated between the Mediterranean MWL and Global MWL. Spring and river water isotope values vary between?7.1 and?4.1 ‰, and?38 and?25 ‰ for δ¹⁸O and δ²H, respectively, responding to winter snowmelt and evaporation. This work implements stable isotopes and hydro-chemical information of springs and river water to understand hydrological and hydro-geological interrelations in karstic semi-arid areas and helps to improve the current water resources management practices of western Iran.     

Stable water isotope patterns in a climate change hotspot: the isotope hydrology framework of Corsica (western Mediterranean)

The Mediterranean is regarded as a region of intense climate change. To better understand future climate change, this area has been the target of several palaeoclimate studies which also studied stable isotope proxies that are directly linked to the stable isotope composition of water, such as tree rings, tooth enamel or speleothems. For such work, it is also essential to establish an isotope hydrology framework of the region of interest. Surface waters from streams and lakes as well as groundwater from springs on the island of Corsica were sampled between 2003 and 2009 for their oxygen and hydrogen isotope compositions. Isotope values from lake waters were enriched in heavier isotopes and define a local evaporation line (LEL). On the other hand, stream and spring waters reflect the isotope composition of local precipitation in the catchment. The intersection of the LEL and the linear fit of the spring and stream waters reflect the mean isotope composition of the annual precipitation (δ_P) with values of?8.6(±0.2) ‰ for δ¹⁸O and?58(±2) ‰ for δ²H. This value is also a good indicator of the average isotope composition of the local groundwater in the island. Surface water samples reflect the altitude isotope effect with a value of?0.17(±0.02) ‰ per 100 m elevation for oxygen isotopes. At Vizzavona Pass in central Corsica, water samples from two catchments within a lateral distance of only a few hundred metres showed unexpected but systematic differences in their stable isotope composition. At this specific location, the direction of exposure seems to be an important factor. The differences were likely caused by isotopic enrichment during recharge in warm weather conditions in south-exposed valley flanks compared to the opposite, north-exposed valley flanks.     

Deuterium and Oxygen-18 in Surface Waters of GDR draining to the Baltic Sea

A general view is presented of deuterium and ¹⁸O measurements of water samples collected at running and standing surface waters in German Democratic Republic. The values confirm earlier observations that the surface waters are influenced by evaporation with respect to the isotopic composition of groundwater. Nevertheless, stronger evaporation effects are restricted to larger lakes. The amount of surface water discharge from GDR to the Baltic Sea and the δD and δ¹⁸O values are discussed. The river Oder provides about 90% of the whole surface run-off. The other watercourses to the coast are unimportand. The mean heavy isotope content of surface run-off was calculated to be ?8.3‰ for δ¹⁸O and ?61‰ for δD (vs. SMOW), respectively.     

First field-based observations of δ2H and δ18O values of event-based precipitation,rivers and other water bodies in the Dzungarian Gobi,SW Mongolia

For certain remote areas like Mongolia, field-based precipitation, surface and ground water isotopic data are scarce. So far no such data exist for the Mongolian Gobi desert, which hinders the understanding of isotopic fractionation processes in this extreme, arid region. We collected 26 event-based precipitation samples, 39 Bij river samples, and 75 samples from other water bodies in the Dzungarian Gobi in SW Mongolia over a period of 16 months for hydrogen and oxygen stable isotope analysis. δ²H and δ¹⁸O values in precipitation show high seasonal variation and cover an extreme range: 175?‰ for δ²H and 24?‰ for δ¹⁸O values. The calculated local meteoric water line (LMWL) shows the isotopic characteristics of precipitation in an arid region. Individual water samples fall into one of three groups: within, above or below the 95?% confidence interval of LMWL. Data presented provide a basis for future studies in this region.     

Distribution of stable isotopes in surface water along the Danube River in Serbia†

Stable hydrogen and oxygen isotopes were analysed in water samples from the River Danube and its tributaries during a longitudinal survey performed in August 2005 on Serbian territory. Danube river water data ranged from?80‰ to?66‰ for δ²H, and from?11.2‰ to?9.3‰ for δ¹⁸O with δ values increasing downstream. The isotopic signatures of the adjacent tributaries (the Tisza, the Sava and the Velika Morava) sampled at the locations close to their confluence with the Danube (Titel, Ostru?nica and Ljubi?evski most, respectively) just about the time of the campaign were enriched (?67‰ and?63‰ for δ²H, and?9.3‰ and?8.9‰ for δ¹⁸O) with respect to the Danube water because of their catchment effects. Hydrogen and oxygen stable isotope values were used in combination with measured physico-chemical and biological parameters to trace hydrological and transport processes in these river systems. The mixing relationships between the Danube main stream and its tributaries were estimated using the mass balance for isotopic composition and electrical conductivity as conservative parameters. Evidence of an incomplete mixing process at the ?enta location, 8 km below the confluence of the Tisza river, with its participation of 88% was shown by its oxygen-18 content. The correlations between river water isotope composition and physico-chemical and biological parameters are discussed.     

Pleistocene age paleo-groundwater inferred from water-stable isotope values in the central part of the Baltic Artesian Basin

A new data set of δ²H and δ¹⁸O in the groundwater from the central part of the Baltic Artesian Basin is presented. The hydrogeological section is subdivided into stagnation, slow exchange and active exchange zones. Na–Ca–Cl brine found at the deepest part – the stagnation zone – is characterized by δ¹⁸O values above ?5?‰ and δ²H values approaching ?40?‰ with respect to Vienna Standard Mean Ocean Water. The slow exchange zone where waters of mostly intermediate salinity reside is characterized by δ¹⁸O values around ?11.7?‰ and δ²H values around ?85.3?‰. Mean δ¹⁸O and δ²H values of the fresh groundwater in the active water exchange zone are ?11.1 and ?79.9?‰, respectively. Characteristically, the groundwater in the active and slow exchange zone is isotopically more depleted compared with the precipitation values observed, and the depletion increases with depth down to the level where strongly enriched brines are encountered.     

Sources and circulation of water and arsenic in the Giant Mine,Yellowknife, NWT,Canada

Recovery of gold from arsenopyrite-hosted ore in the Giant Mine camp, Yellowknife, NWT, Canada, has left a legacy of arsenic contamination that poses challenges for mine closure planning. Seepage from underground chambers storing some 237,000 tonnes of arsenic trioxide dust, has As concentrations exceeding 4000 ppm. Other potential sources and sinks of As also exist. Sources and movement of water and arsenic are traced using the isotopes of water and sulphate. Mine waters (16 ppm As; As^V/As^III ≈ 150) are a mixture of two principal water sources – locally recharged, low As groundwaters (0.5 ppm As) and Great Slave Lake (GSL; 0.004 ppm As) water, formerly used in ore processing and discharged to the northwest tailings impoundment (NWTP). Mass balance with δ¹⁸O shows that recirculation of NWTP water to the underground through faults and unsealed drillholes contributes about 60% of the mine water. ;[emsp]>Sulphate serves to trace direct infiltration to the As₂O₃ chambers. Sulphate in local, low As groundwaters (0.3–0.6 ppm As; δ³⁴S_SO4  ～ 4 ‰ and δ¹⁸O_SO4  ～ ? 10 ‰) originates from low-temperature aqueous oxidation of sulphide-rich waste rock. The high As waters gain a component of ¹⁸O-enriched sulphate derived from roaster gases (δ¹⁸O_SO4  = + 3.5 ‰), consistent with their arsenic source from the As₂O₃ chambers. High arsenic in NWTP water (～ 8 ppm As; δ¹⁸O_SO4  = ? 2 ‰) derived from mine water, is attenuated to close to 1 ppm during infiltration back to the underground, probably by oxidation and sorption by ferrihydrite.     

Isotopic composition of bottled water in Saudi Arabia

The ¹⁸O/¹⁶O and ²H/¹H ratios of 18 water brands representing the most popular bottled water brands in the Saudi market were measured using a system based on the latest advancements in tunable off-axis integrated cavity output diode laser spectroscopy (OA-ICOS) in the near-infrared spectral region. Utilizing δ¹⁸O and the δ²H values of locally produced water samples, a meteoric water line (δ²H?=?7.84 δ¹⁸O?+?2.11) was extracted and found to be consistent with the slope of the global meteoric water line (GMWL) and the geographic location of Saudi Arabia.     

Hydrogeochemical and isotopic characterisation of groundwater in a sand-dune phreatic aquifer on the northeastern coast of the province of Buenos Aires,Argentina

This contribution presents the hydrochemical and isotopic characterisation of the phreatic aquifer located in the Partido de la Costa, province of Buenos Aires, Argentina. In the sand-dune barrier geomorphological environment, groundwater is mainly a low-salinity Ca-HCO₃ and Na-HCO₃-type, being in general suitable for drinking, whereas in the continental plain (silty clay sediments), groundwater is a Na-Cl type with high salinity and unsuitable for human consumption. The general isotopic composition of the area ranges from?6.8 to?4.3 ‰ for δ¹⁸O and from?39 to?21 ‰ for δ²H, showing that rainwater rapidly infiltrates into the sandy substrate and reaches the water table almost without significant modification in its isotopic composition. These analyses, combined with other chemical parameters, made it possible to corroborate that in the eastern area of the phreatic aquifer, there is no contamination from marine salt water.     

Paleoclimatology

The Lamas Basin is an area covering ～4400 km² situated on the eastern Mediterranean coast of Turkey covered with highly karstified limestone and dolomitic limestone from the Miocene and Mesozoic age, respectively. Owing to the area’s low karstification basement, groundwater in the karst aquifer circulates deep from the surface towards the springs along the coast as well as to the submarine springs. This study aims working out the salinization level and recharge characteristics of the Lamas Basin using environmental isotopes techniques. In the study, the data collected previously to discover, in general terms, the groundwater characteristics within the area are reanalyzed to fulfil the purpose of the study. In conclusion, it is found that the down gradient karst springs discharging along the Mediterranean coast mostly contain groundwater contributions from higher altitudes with depleted δ¹⁸O and δ²H compositions. The δ¹⁸O-altitude effect was determined as approximately?0.12 ‰/100 m which may indicate sea-spray intrusion towards inland. As a result, the salinization level of coastal springs changes ranging between 1.2 % and 17.0 %. Owing to the seawater encroachment, Ca–HCO₃ water type changes to Na–HCO₃ or Na-Cl water by the cation exchange during the dry period. As the unique freshwater potential extends along the coastal area, the groundwater production should be exploited in a way that seawater encroachment is kept at minimum.     

There is no Temperature Dependence of Net Biochemical Fractionation of Hydrogen and Oxygen Isotopes in Tree-Ring Cellulose

Abstract

The isotopic composition of tree-ring cellulose was obtained over a two-year period from small diameter, riparian zone trees along an elevational transect in Big Cottonwood Canyon, Utah, USA to test for a possible temperature dependence of net biological fractionation during cellulose synthesis. The isotope ratios of stream water varied by only 3.6‰ and 0.2‰ in δD and δ¹⁸O, respectively, over an elevation change of 810m. The similarity in stream water and macroenvironment over the short (13km) transect produced nearly constant stem and leaf water δD and δ¹⁸O values. In addition, what few seasonal variations observed in the isotopic composition of source water and atmospheric water vapor or in leaf water evaporative enrichment were experienced equally by all sites along the elevational transect. The temperature at each site along the transect spanned a range of ≥ 5°C as calculated using the adiabatic lapse rate. Since the δD and δ¹⁸O values of stem and leaf water varied little for these trees over this elevation/ temperature transect, any differences in tree-ring cellulose δD and δ¹⁸O values should have been associated with temperature effects on net biological fractionation. However, the slopes of the regressions of elevation versus the δD and δ¹⁸O values of tree-ring cellulose were not significantly different from zero indicating little or no temperature dependence of net biological fractionation. Therefore, cross-site climatic reconstruction studies using the isotope ratios of cellulose need not be concerned that temperatures during the growing season have influenced results.     

Influence of the balance of the intertropical front on seasonal variations of the isotopic composition in rainfall at Kisiba Masoko (Rungwe Volcanic Province,SW, Tanzania)

Tropical rainfall isotopic composition results from complex processes. The climatological and environmental variability in East Africa increases this complexity. Long rainfall isotope datasets are needed to fill the lack of observations in this region. At Kisiba Masoko, Tanzania, rainfall and rain isotopic composition have been monitored during 6 years. Mean year profiles allow to analyse the seasonal variations. The mean annual rainfall is 2099?mm with a rain-weighted mean composition of ?3.2?‰ for δ¹⁸O and ?11.7?‰ for δ²H. The results are consistent with available data although they present their own specificity. Thus, if the local meteoric water line is δ²H?=?8.6 δ¹⁸O?+?14.8, two seasonal lines are observed. The seasonality of the isotopic composition in rain and deuterium excess has been compared with precipitating air masses backtracking trajectories to characterize a simple scheme of vapour histories. The three major oceanic sources have two moisture signatures with their own trajectory histories: one originated from the tropical Indian Ocean at the beginning of the rainy season and one from the Austral Ocean at its end. The presented isotopic seasonality depends on the balance of the intertropical front and provides a useful dataset to improve the knowledge about local processes.     

A Repaid Procedure for Preparing Oxyen-18 Determination in Water Samples

An equipment for the speed δ¹⁸O analysis of water samples is described. It used the equilibrium isotopic exchange reaction between water and CO₂ gas. Outgasing of samples through capillary without freezing down the samples, together with shaking during the equilibrium time, reduced considerably time for sample preparation.

Apparatus is air termostated with hand valves. Measured δ values are not very sensitive to precision of preparation work and reaction conditions, except of temperature. With good temperature control the standard reproducibility of single measurement is better than 0,1‰     

Evaluation of the Sulfate Dynamics in Groundwater by Means of Environmental Isotopes

Abstract

Elevated sulfate concentrations and their heterogeneous distribution in the drinking water catchment area Torgau-Mockritz (Germany) were investigated by means of multiple isotope signatures such as δ³⁴S, δ¹⁸O-H₂O, δD, tritium, and ⁸⁵Kr. δ³⁴S values of the groundwater sulfate vary between -19…+ 37‰ CDT. No simple correlation exists between sulfate concentrations and δ³⁴S. Superimposition of different sulfur sources and mobilization processes combined with a complicated groundwater movement create a complex distribution pattern. The oxidation of reduced sedimentary sulfur has to be regarded as a main source of dissolved sulfate at least regionally. Tritium and ¹⁴C data revealed that old groundwater can be excluded as source for high sulfate contents. Correlated temporal variations in the concentrations of tritium and sulfate are observed in deeper sampling positions. Highly variable δ¹⁸O and δD, as detected in parts of the catchment area, indicate local influences of surface water infiltration into the aquifer. The spatial distribution of isotope signatures enables the identification of zones with descending younger water or hindered groundwater movement and hence provides useful hints for flow modeling.