[15N]Methacetin-und [15N]Ammoniumtest zur Leberfunktionsprüfung im Kindesalter

The stable isotope content of samples of precipitation and of the river water throughout the Piracicaba basin in Brazil was measured over a two-year period. The isotope values of precipitation follow a consistent pattern of relatively depleted values of both deuterium and oxygen 18 during the rainy summers and enriched ones during the dry winters, with all values aligned slightly above the Global Meteoric Water Line. The isotopic composition of the river water throughout the basin shows a remarkable spatial coherence and much smaller scatter of data than those of the precipitation. The isotope composition of river water is close to that of the precipitation in the rainy season, however, with a consistent lower d-excess value by 1‰–2‰. This is attributed to evaporative water loss in the basin, in part an expression of the recycling of water due to the anthropogenic activity in the region. The more divergent values are recorded during high-water stages in the rivers. In many cases, the floods during the beginning of the rainy season are characterized by an enrichment of the heavy isotopes and lower d-excess values when compared to the precipitation, with the opposite situation later in the rainy season. This is interpreted as resulting from the watershed/riverflow interaction pattern, and it thus suggests that the isotope composition can monitor the hydrologic situation in the basin and its changes.     

Spatial and temporal characteristics of stable isotopes in the Tarim River Basin

By using 233 isotope samples, we investigated the spatial and temporal variations of δ¹⁸O and δ²H in precipitation and surface water, and the contribution of different water sources in the rivers within the Tarim River Basin (TRB), which receives snow/glacier meltwater, groundwater, and rainfall. Our study revealed a similar seasonal pattern of precipitation δ¹⁸O and δ²H at both the north and south edges of the basin, indicating the dominant effect of westerly air masses in the summer and the combined influence of westerly and polar air masses during the winter, although the southern part showed more complex precipitation processes in the summer. River water in the basin has relatively large temporal variations in both δ¹⁸O and δ²H showing a distinct seasonal pattern with lower isotope values in May than in September. Higher d-excess values throughout the year in the Aksu river and the Tizinafu river suggest that water may be intensively recycled in the mountains of the TRB. Based on isotopic hydrograph separation, we found that groundwater is the main water source that discharges the entire basin although individual rivers vary.     

The isotope altitude effect reflected in groundwater: a case study from Slovenia

This paper presents the stable isotope data of oxygen (δ¹⁸O) and hydrogen (δ²H) in groundwater from 83 sampling locations in Slovenia and their interpretation. The isotopic composition of water was monitored over 3 years (2009–2011), and each location was sampled twice. New findings on the isotopic composition of sampled groundwater are presented, and the data are also compared to past studies regarding the isotopic composition of precipitation, surface water, and groundwater in Slovenia. This study comprises: (1) the general characteristics of the isotopic composition of oxygen and hydrogen in groundwater in Slovenia, (2) the spatial distribution of oxygen isotope composition (δ¹⁸O) and d-excess in groundwater, (3) the groundwater isotope altitude effect, (4) the correlation between groundwater d-excess and the recharge area altitude of the sampling location, (5) the relation between hydrogen and oxygen isotopes in groundwater in comparison to the global precipitation isotope data, (6) the groundwater isotope effect of distance from the sea, and (7) the estimated relation between the mean temperature of recharge area and δ¹⁸O in groundwater.     

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.     

Deuterium excess in precipitation of Alpine regions - moisture recycling

The paper evaluates long-term seasonal variations of the deuterium excess (d-excess = delta(2)H - 8. delta(18)O) in precipitation of stations located north and south of the main ridge of the Austrian Alps. It demonstrates that sub-cloud evaporation during precipitation and continental moisture recycling are local, respectively, regional processes controlling these variations. In general, sub-cloud evaporation decreases and moisture recycling increases the d-excess. Therefore, evaluation of d-excess variations in terms of moisture recycling, the main aim of this paper, includes determination of the effect of sub-cloud evaporation. Since sub-cloud evaporation is governed by saturation deficit and distance between cloud base and the ground, its effect on the d-excess is expected to be lower at mountain than at lowland/valley stations. To determine quantitatively this difference, we examined long-term seasonal d-excess variations measured at three selected mountain and adjoining valley stations. The altitude differences between mountain and valley stations ranged from 470 to 1665 m. Adapting the 'falling water drop' model by Stewart [J. Geophys. Res., 80(9), 1133-1146 (1975).], we estimated that the long-term average of sub-cloud evaporation at the selected mountain stations (altitudes between about 1600 and 2250 m.a.s.l.) is less than 1 % of the precipitation and causes a decrease of the d-excess of less than 2 per thousand. For the selected valley stations, the corresponding evaporated fraction is at maximum 7 % and the difference in d-excess ranges up to 8 per thousand. The estimated d-excess differences have been used to correct the measured long-term d-excess values at the selected stations. Finally, the corresponding fraction of water vapour has been estimated that recycled by evaporation of surface water including soil water from the ground. For the two mountain stations Patscherkofel and Feuerkogel, which are located north of the main ridge of the Alps, the maximum seasonal change of the corrected d-excess (July/August) has been estimated to be between 5 and 6 per thousand, and the corresponding recycled fraction between 2.5-3 % of the local precipitation. It has been found that the estimated recycled fractions are in good agreement with values derived from other approaches.     

Note on the spring region of Gacka River (Croatia)

We present the first results of a study of the Gacka River spring area, an important Croatian drinking water resource. Stable isotope data (obtained at the Stable Isotope Laboratory SILab in Rijeka) are used in combination with hydrological and meteorological data. The delta18O values give information on the mean catchment altitudes of the three main springs of Gacka River (Majerovo vrelo, Tonkovica vrelo and Pecina). Hydrological, meteorological and stable isotope data indicate good mixing of infiltrated and ground waters. The precipitation d-excess shows a seasonally varying influence of continental and maritime air masses.     

Note on the spring region of Gacka River (Croatia)†

We present the first results of a study of the Gacka River spring area, an important Croatian drinking water resource. Stable isotope data (obtained at the Stable Isotope Laboratory SILab in Rijeka) are used in combination with hydrological and meteorological data. The δ¹⁸O values give information on the mean catchment altitudes of the three main springs of Gacka River (Majerovo vrelo, Tonkovi?a vrelo and Pe?ina). Hydrological, meteorological and stable isotope data indicate good mixing of infiltrated and ground waters. The precipitation d-excess shows a seasonally varying influence of continental and maritime air masses.     

Isotopic characteristics of meteoric waters in the Belgrade region

The stable isotope composition of hydrogen (delta(2)H) and oxygen (delta(18)O) 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 delta(2)H=7.8 (+/-0.2) delta(18)O+7.3(+/-1.6) (r(2)=0.98, n=60, sigma=0.52) for the whole period of observation is close to the global meteoric water line. The amount-weighted mean delta(2)H and delta(18)O values of precipitation were-65+/-27 per thousand and-9.4+/-3.4 per thousand, respectively. Good correlation between delta(18)O values (r approximately >0.67) and ambient temperature and relative humidity was obtained. Stream-water data ranged from-94 to-60 per thousand for delta(2)H and from-11.0 to approximately 5.7 per thousand for delta(18)O 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.     

Use of isotopes to study floodplain wetland and river flow interaction in the White Volta River basin,Ghana

Floodplain wetlands influence the timing and magnitude of stream responses to rainfall. In managing and sustaining the level of water resource usage in any river catchment as well as when modelling hydrological processes, it is essential that the role of floodplain wetlands in stream flows is recognised and understood. Existing studies on hydrology within the Volta River basin have not adequately represented the variability of wetland hydrological processes and their contribution to the sustenance of river flow. In order to quantify the extent of floodwater storage within riparian wetlands and their contribution to subsequent river discharges, a series of complementary studies were conducted by utilising stable isotopes, physical monitoring of groundwater levels and numerical modelling. The water samples were collected near Pwalugu on the White Volta River and at three wetland sites adjacent to the river using the grab sampling technique. These were analysed for ¹⁸O and ²H. The analysis provided an estimate of the contribution of pre-event water to overall stream flow. In addition, the variation in the isotopic composition in the river and wetland water samples, respectively, revealed the pattern of flow and exchange of water between the wetlands and the main river system.     

Stable isotope study of precipitation and cave drip water in Florida (USA): implications for speleothem-based paleoclimate studies

Stable isotopes of hydrogen and oxygen were used to examine how the isotopic signal of meteoric water is modified as it travels through soil and epikarst into two caves in Florida. Surface and cave water samples were collected every week from February 2006 until March 2007. The isotopic composition of precipitation at the investigated sites is highly variable and shows little seasonal control. The delta18O vs. delta2H plot shows a mixing line having a slope of 5.63, suggesting evaporation effects dominate the isotopic composition of most rainfall events of less than 8 cm/day, as indicated by their low d-excess values. The delta18O values of the drip water show little variability (<0.6 per thousand), which is loosely tied to local variations in the seasonal amount of precipitation. This is only seen during wintertime at the Florida Caverns site. The lag time of over two months and the lack of any relationship between rainfall amount and the increase in drip rate indicate a dominance of matrix flow relative to fracture/conduit flow at each site. The long residence time of the vadose seepage waters allows for an effective isotopic homogenisation of individual and seasonal rainfall events. We find no correlation between rainfall and drip water delta18O at any site. The isotopic composition of drip water in both caves consistently tends to resemble the amount-weighted monthly mean rainfall input. This implies that the delta18O of speleothems from these two caves in Florida cannot record seasonal cycle in rainfall delta18O, but are suitable for paleoclimate reconstructions at inter-annual time scales.dagger.     

Regional and temporal variability of the isotope composition (O, S) of atmospheric sulphate in the region of Freiberg, Germany, and consequences for dissolved sulphate in groundwater and river water

The isotope composition of dissolved sulphate and strontium in atmospheric deposition, groundwater, mine water and river water in the region of Freiberg was investigated to better understand the fate of these components in the regional and global water cycle. Most of the isotope variations of dissolved sulphates in atmospheric deposition from three locations sampled bi- or tri-monthly can be explained by fractionation processes leading to lower [Formula: see text] (of about 2-3‰) and higher [Formula: see text] (of about 8-10‰) values in summer compared with the winter period. These samples showed a negative correlation between [Formula: see text] and [Formula: see text] values and a weak positive correlation between [Formula: see text] and [Formula: see text] values. They reflect the sulphate formed by aqueous oxidation from long-range transport in clouds. However, these isotope variations were superimposed by changes of the dominating atmospheric sulphate source. At two of the sampling points, large variations of mean annual [Formula: see text] values from atmospheric bulk deposition were recorded. From 2008 to 2009, the mean annual [Formula: see text] value increased by about 5‰; and decreased by about 4‰ from 2009 to 2010. A change in the dominating sulphate source or oxidation pathways of SO(2) in the atmosphere is proposed to cause these shifts. No changes were found in corresponding [Formula: see text] values. Groundwater, river water and some mine waters (where groundwater was the dominating sulphate source) also showed temporal shifts in their [Formula: see text] values corresponding to those of bulk atmospheric deposition, albeit to a lower degree. The mean transit time of atmospheric sulphur through the soil into the groundwater and river water was less than a year and therefore much shorter than previously suggested. Mining activities of about 800 years in the Freiberg region may have led to large subsurface areas with an enhanced groundwater flow along fractures and mined-refilled ore lodes which may shorten transit times of sulphate from precipitation through groundwater into river water.     

Temporal and spatial distribution of isotopes in river water in Central Europe: 50 years experience with the Austrian network of isotopes in rivers

The Austrian network of isotopes in rivers comprises about 15 sampling locations and has been operated since 1976. The Danube isotope time series goes back to 1963. The isotopic composition of river water in Central Europe is mainly governed by the isotopic composition of precipitation in the catchment area; evaporation effects play only a minor role. Short-term and long-term isotope signals in precipitation are thus transmitted through the whole catchment. The influence of climatic changes has become observable in the long-term stable isotope time series of precipitation and surface waters. Environmental ³H values were around 8 TU in 2015, short-term ³H pulses up to about 80 TU in the rivers Danube and March were a consequence of releases from nuclear power plants. The complete isotope data series of this network will be included in the Global Network of Isotopes in Rivers database of the International Atomic Energy Agency (IAEA) in 2017. This article comprises a review of 50 years isotope monitoring on rivers and is also intended to provide base information on the (isotope-)hydrological conditions in Central Europe specifically for the end-users of these data, e.g. for modelling hydrological processes. Furthermore, this paper includes the 2006–2015 supplement adding to the Danube isotope set published earlier.     

Insights from stable isotopes of water and hydrochemistry to the evolutionary processes of groundwater in the Subei lake basin,Ordos energy base,Northwestern China

ABSTRACT

Changes in groundwater evolutionary processes due to aquifer overexploitation show a world-wide increase and have been of growing concern in recent years. The study aimed to improve the knowledge of groundwater evolutionary processes by means of stable water isotopes and hydrochemistry in a representative lake basin, Ordos energy base. Groundwater, precipitation, and lake water collected during four campaigns were analysed by stable isotopes and chemical compositions. Results showed that temperature effect predominated the isotope fractionation in precipitation, while evaporation and inadequate groundwater recharge were the key factors explaining high salinity and isotopic enrichment in lake water. Additionally, the Kuisheng Lake was a preferential area of groundwater recharge, while the Subei Lake received less sources from underlying aquifer due to the combined effects of low permeable zone and upstream groundwater captured by the production wells. The homogeneous isotope signatures of groundwater may be ascribed to the closely vertical hydraulic connectivity between the unconfined and the confined aquifers. Isotopically enriched groundwater pumping from well field probably promoted isotopic depletion in groundwater depression cone. These findings not only provide the conceptual framework for the inland basin, but also have important implications for sustainable groundwater management in other groundwater discharge basins with arid climate.     

Isotopic fingerprint of the middle Olt River basin,Romania

One of the most important tributaries of the Danube River in Romania, the Olt River, was characterized in its middle catchment in terms of the isotopic composition using continuous flow–isotope ratio mass spectrometry (CF–IRMS). Throughout a period of 10 months, from November 2010 to August 2011, water samples from the Olt River and its more important tributaries were collected in order to investigate the seasonal and spatial isotope patterns of the basin waters. The results revealed a significant difference between the Olt River and its tributaries, by the fact that the Olt River waters show smaller seasonal variations in the stable isotopic composition and are more depleted in ¹⁸O and ²H. The waters present an overall enrichment in heavy isotopes during the warm seasons.     

中国东北区域盛夏雨季的客观识别

鉴于我国东北三省雨季客观识别方法不尽相同,且无东北区域统一的雨季监测指标.为了更好地开展区域关键天气过程的客观化识别和监测,本文从区域角度出发,采用东北三省102站逐日降水量资料,通过对东北区域多年平均5点平滑处理的4月1日—10月31日逐日降水量序列的综合分析,及对历年逐日滑动平均雨量的对比试验,确定了东北盛夏雨季判别的阈值参数及通过阈值后的持续时间参数,进而研发了适合东北区域盛夏雨季开始和结束日期的客观识别方法.并采用美国环境预报中心和国家大气研究中心逐日再分析的风场、位势高度场资料,通过对盛夏雨季前、中、后期不同高度层大气环流场的对比分析,验证了该客观识别方法的合理性.结果表明,东北区域1981—2010年气候态平均的盛夏雨季的起止日期分别为每年的6月26日和8月30日.     

Sulfur and oxygen isotope geochemistry of acid mine drainage--the polymetallic sulfide deposit "himmelfahrt fundgrube" in Freiberg (Germany)

We investigated physical, chemical and isotope (S, O) parameters of sulfate from acid mine drainage from the polymetallic sulfide ore deposit Freiberg (Gennany), which was mined for more than eight hundred years. Two main groups of water were distinguished: 1. Flowing mine water with sulfate concentrations of less than 9,000 mg/l and pH values higher than 3.2, 2. Pore water in weathered low grade ores and pools with sulfate concentrations higher than 9000mg/l and pH values below 3.2. The sulfur and oxygen isotope composition of sulfate from flowing mine waters reflects mixing of sulfate from two sulfur sources: a) atmospheric sulfur from precipitation and b) sulfate formed as a result of sulfide oxidation processes. Sulfur isotope values of mine water sulfate were used to estimate the contribution of sulfate derived through oxidation of sulfides. The sulfur isotope composition of pore water sulfate and precipitated sulfate (jarosite) from weathered low grade ore samples is identical to the sulfur isotope composition of primary sulfides. The oxygen isotope composition of pore water sulfate from low grade ore samples indicates that the oxidation process proceeds relatively slowly in 02-depleted waters, probably without significant microbial catalysis.     

Sulfur and Oxygen Isotope Geochemistry of Acid Mine Drainage—The Polymetallic Sulfide Deposit “Himmelfahrt Fundgrube” in Freiberg (Germany)

Abstract

We investigated physical, chemical and isotope (S, O) parameters of sulfate from acid mine drainage from the polymetallic sulfide ore deposit Freiberg (Germany), which was mined for more than eight hundred years. Two main groups of water were distinguished:

1. Flowing mine water with sulfate concentrations of less than 9000 mg/1 and pH values higher than 3.2

2. Pore water in weathered low grade ores and pools with sulfate concentrations higher than 9000 mg/1 and pH values below 3.2.

The sulfur and oxygen isotope composition of sulfate from flowing mine waters reflects mixing of sulfate from two sulfur sources: a) atmospheric sulfur from precipitation and b) sulfate formed as a result of sulfide oxidation processes. Sulfur isotope values of mine water sulfate were used to estimate the contribution of sulfate derived through oxidation of sulfides. The sulfur isotope composition of pore water sulfate and precipitated sulfate (jarosite) from weathered low grade ore samples is identical to the sulfur isotope composition of primary sulfides. The oxygen isotope composition of pore water sulfate from low grade ore samples indicates that the oxidation process proceeds relatively slowly in O₂-depleted waters, probably without significant microbial catalysis.     

Multifractal analysis of streamflow records of the East River basin (Pearl River), China

Scaling behaviors of the long daily streamflow series of four hydrological stations (Longchuan (1952-2002), Heyuan (1951-2002), Lingxia (1953-2002) and Boluo (1953-2002)) in the mainstream East River, one of the tributaries of the Pearl River (Zhujiang River) basin, were analyzed using multifractal detrended fluctuation analysis (MF-DFA). The research results indicated that streamflow series of the East River basin are characterized by anti-persistence. MF-DFA technique showed similar scaling properties in the streamflow series of the East River basin on shorter time scales, indicating universal scaling properties over the East River basin. Different intercept values of the fitted lines of log-log curve of F_q(s) versus s implied hydrological regulation of water reservoirs. Based on the numerical results, we suggested that regulation activities by water reservoirs could not impact the scaling properties of the streamflow series. The regulation activities by water reservoir only influenced the fluctuation magnitude. Therefore, we concluded that the streamflow variations were mainly the results of climate changes, and precipitation variations in particular. Strong dependence of generalized Hurst exponent h(q) on q demonstrated multifractal behavior of streamflow series of the East River basin, showing ‘universal’ multifractal behavior of river runoffs. The results of this study may provide valuable information for prediction and assessment of water resources under impacts of climatic changes and human activities in the East River basin.     

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.     

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.