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Bottled natural mineral waters from an andesitic aquifer in Slovenia are enriched in magnesium (1.1 g/l), sulphate (2.2 g/l) and dissolved inorganic carbon (204 g/l). We analysed major ions, trace elements, tritium activity, 14 C, δ 18 O H2O , δ 2 H H2O, δ 13 C DIC , gas composition and noble gases in six wells. In addition, 87 Sr/ /86 Sr, δ 34 S SO4 and δ 11 B were analysed here for the first time. Stable isotopes with δ 18 O = -11.97 to -10.30‰ and δ 2 H = -77.3 to -63.8 confirm meteoric origin. CO 2 degassing is evident at three wells, causing the oxygen shift of about -1.3‰. Tritium activity was detectable only in the shallowest well, where the freshwater component was dated to the 1960s. δ 13 C DIC in five waters is -1.78 to + 1.33‰, typical of carbonate dissolution. Radiocarbon is low, 1.03-5.16 pMC. Chemical correction with bicarbonate concentration and δ 13 C correction methods gave best mean residence times, slightly longer than previously published. Sulphate has δ 34 S 26.6-28.9‰ and δ 18 O 8.9-11.1‰ due to dissolution of evaporites in carbonate rocks. Boron at concentrations of 1.2-6.1 mg/l has two origins: δ 11 B = 11.3-16.4‰ from hydrothermal alteration and δ 11 B = 26.6-31.7‰ from carbonate dissolution. Strontium at concentrations of 0.5-22.0 mg/l has 87 Sr/ /86 Sr, indicating three sources: 0.7106 for Miocene clastic rocks, 0.7082 for Triassic carbonates and 0.7070 for Lower Oligocene andesitic rocks. CO 2 represents the majority of the dissolved (> 98.84 vol%) and separated gas (> 95.23 vol%). Methane is only found in two wells with a max. of 0.30 vol%. All waters show excess helium and 16-97% of mantle-derived helium. Since all show subsurface degassing, the paleo-infiltration temperature could not be calculated., (© 2021. The Author(s).)

The Aconcagua river basin (Chile, 32 °S) has suffered the effects of the megadrought over the last decade. The severe snowfall deficiency drastically modified the water supply to the catchment headwaters. Despite the recognized snowmelt contribution to the basin, an unknown streamflow buffering effect is produced by glacial, periglacial and groundwater inputs, especially in dry periods. Hence, each type of water source was characterized and quantified for each season, through the combination of stable isotope and ionic analyses as natural water tracers. The δ18O and electric conductivity were identified as the key parameters for the differentiation of each water source. The use of these parameters in the stable isotope mixing “simmr” model revealed that snowmelt input accounted 52% in spring and only 22–36% during the rest of the year in the headwaters. While glacial supply contributed up to 34%, both groundwater and periglacial exhibited a remarkable contribution around 20% with some seasonal variations. Downstream, glacial contribution averaged 15–20%, groundwater seasonally increased up to 46%, and periglacial input was surprisingly high (i.e., 14–21%). The different water sources contribution quantification over time for the Aconcagua River reported in this work provides key information for water security in this territory.

Forested wetlands dominated by black ash ( Fraxinus nigra) are currently threatened by the rapid expansion of the exotic emerald ash borer (EAB; Agrilus planipennis , Coleoptera: Buprestidae) in North America, and very little is known about the hydrology and ecology of black ash wetlands. The ecohydrological response of forested wetlands following a canopy disturbance has the potential to affect critical ecosystem services, and the degree of this effect may largely depend on the wetland's hydrogeological setting. The main objectives of this study were to characterize the hydrologic connectivity of uninfested black ash wetlands and evaluate the water table response to a simulated EAB disturbance. We hypothesized that black ash wetlands in northern Michigan were (a) seasonally connected to, and derived the majority of their water from groundwater, and (b) wetland water tables would be elevated following a simulated EAB infestation due to decreased transpiration with the loss of black ash. The results indicate that the black ash wetland sites received most of their water from groundwater discharge. Significantly smaller site transpiration fluxes and significantly slower rates of drawdown were detected during the growing season in the girdled and ash-cut treatment sites, and these responses collectively produced significantly elevated wetland water tables when compared to control sites in the latter portions of the growing season. However, the wetlands' strong connection with groundwater sources likely buffered the magnitude of hydrological responses associated with the loss of black ash from the landscape. [ABSTRACT FROM AUTHOR]

The mean residence time (MRT) of karst groundwater in three mountainous catchments of the Western Himalaya was estimated using multiple approaches: the tritium method, the sine wave model and tracer tests. Water samples were collected from precipitation, glacier melt, streams and karst springs for δ2H and tritium analysis during 2012 and 2013. High tritium values were observed in winter precipitation and low values in summer precipitation. The variation of tritium in karst springs was similar to that of the streams, whereas glacier melt showed lower tritium values. The MRT of cold karst springs was shorter than that of warm karst springs. The tracer breakthrough curves (TBC) retrieved for different springs suggested a short travel time for groundwater and possibly conduit flow. Deterioration of water quality and variation in flux magnitude are the two main practical consequences of the short travel time of karst groundwater in the region.EDITOR D. KoutsoyiannisASSOCIATE EDITOR K. Heal [ABSTRACT FROM PUBLISHER]

Highlights: [•] Natural tracers reveal interaction between esker aquifer and connected surface waters. [•] Groundwater flow systems are distinguishable with repeated seepage measurements. [•] The subsurface may act as a phosphate source for surface water bodies. [Copyright &y& Elsevier]

Summary: The Lez karst spring, the main perennial outlet of the Lez karst system in southern France, plays an important role in supplying drinking water to the Montpellier metropolitan region. In order to investigate the origin of groundwater, its circulation patterns, and to understand the connectivity and compartmentalization of a karst system, a multi-tracer approach was used to describe the hydrogeology of the Lez karst system. Groundwater samples were collected from Lez karst during a range of hydrologic conditions (between March 2006 and August 2009) and analyzed for major and trace elements, total organic carbon, fecal, and total coliform. During the first recharge event of autumn, highly-mineralized water was observed at Lez Spring during the studied years. Multiple parameters of water during this rise were monitored with a fine time-step in 2008. Discriminate Factorial Analyses revealed the existence of different water-types discharging at Lez Spring. During high stage periods, highly mineralized water initially discharges from the spring, followed by rapid infiltration water. This behavior suggests that hydrodynamics affect groundwater circulation by soliciting different endmembers. These characteristics were observed on a larger scale when monitoring three intermittent springs connected to Lez Spring. A detailed analysis using bivariate diagrams of major, trace elements and elemental ratios provided insight into different water origins, associated lithologies, and mineral-solution reactions related to hydrodynamic responses. From the five identified water-types, the two more contrasting ones are emphasized: the first one corresponds to the most geochemically evolved waters, issued from deep layers where evaporite chemical fingerprinting has been identified. They are characterized by high mineralization and high concentrations in Cl, Na, Mg, Li, B and Br elements, and high Sr/Ca, Mg/Ca and Cl/Br ratios. The second water-type corresponds to the most diluted (low mineralized) waters with high concentrations of NO3, bacteria, Total Organic Carbon (TOC), and represents the flux of rapid infiltration waters. This endmember underlines the vulnerability of the system to surface infiltration and anthropogenic contamination through the infiltration of water via sinkholes and well-developed fracture networks. [Copyright &y& Elsevier]

The Aconcagua river basin (Chile, 32 °S) has suffered the effects of the megadrought over the last decade. The severe snowfall deficiency drastically modified the water supply to the catchment headwaters. Despite the recognized snowmelt contribution to the basin, an unknown streamflow buffering effect is produced by glacial, periglacial and groundwater inputs, especially in dry periods. Hence, each type of water source was characterized and quantified for each season, through the combination of stable isotope and ionic analyses as natural water tracers. The δ18O and electric conductivity were identified as the key parameters for the differentiation of each water source. The use of these parameters in the stable isotope mixing "simmr" model revealed that snowmelt input accounted 52% in spring and only 22–36% during the rest of the year in the headwaters. While glacial supply contributed up to 34%, both groundwater and periglacial exhibited a remarkable contribution around 20% with some seasonal variations. Downstream, glacial contribution averaged 15–20%, groundwater seasonally increased up to 46%, and periglacial input was surprisingly high (i.e., 14–21%). The different water sources contribution quantification over time for the Aconcagua River reported in this work provides key information for water security in this territory. [ABSTRACT FROM AUTHOR]