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Groundwater pollution threatens human and ecosystem health in many regions around the globe. Fast flow to the groundwater through focused recharge is known to transmit short-lived pollutants into carbonate aquifers, endangering the quality of groundwaters where one quarter of the world’s population lives. However, the large-scale impact of such focused recharge on groundwater quality remains poorly understood. Here, we apply a continental-scale model to quantify the risk of groundwater contamination by degradable pollutants through focused recharge in the carbonate rock regions of Europe, North Africa, and the Middle East. We show that focused recharge is the primary reason for widespread rapid transport of contaminants to the groundwater. Where it occurs, the concentration of pollutants in groundwater recharge that have not yet degraded increases from <1% to around 20 to 50% of their concentrations during infiltration. Assuming realistic application rates, our simulations show that degradable pollutants like glyphosate can exceed their permissible concentrations by 3 to 19 times when reaching the groundwater. Our results are supported by independent estimates of young water fractions at 78 carbonate rock springs over Europe and a dataset of observed glyphosate concentrations in the groundwater. They imply that in times of continuing and increasing industrial and agricultural productivity, focused recharge may result in an underestimated and widespread risk to usable groundwater volumes.

Excess nitrogen (N) deposition and gaseous N emissions from industrial, domestic, and agricultural sources have led to increased nitrate leaching, the loss of biological diversity, and has affected carbon (C) sequestration in forest ecosystems. Nitrate leaching affects the purity of karst water resources, which contribute around 50% to Austria’s drinking water supply. Here we present an evaluation of the drivers of dissolved inorganic N (DIN) concentrations and fluxes from a karst catchment in the Austrian Alps (LTER Zöbelboden) from 27 years of records. In addition, a hydrological model was used together with climatic scenario data to predict expected future runoff dynamics. The study area was exposed to increasing N deposition during the 20th century (up to 30 to 35 kg N ha−1 y−1), which are still at levels of 25.5 ± 3.6 and 19.9 ± 4.2 kg N ha−1 y−1 in the spruce and the mixed deciduous forests, respectively. Albeit N deposition was close to or exceeded critical loads for several decades, 70–83% of the inorganic N retained in the catchment from 2000 to 2018, and NO3- concentrations in the runoff stayed <10 mg L−1 unless high-flow events occurred or forest stand-replacing disturbances. We identified tree growth as the main sink for inorganic N, which might together with lower runoff, increase retention of only weakly decreasing N deposition in the future. However, since recurring forest stand-replacement is predicted in the future as a result of a combination of climatically driven disturbance agents, pulses of elevated nitrate concentrations in the catchment runoff will likely add to groundwater pollution.

Pod Hradem Cave, located in the Moravian Karst, Czech Republic, offers an excellent opportunity for environmental reconstructions of Marine Isotope Stage 3 (MIS 3) in Central Europe due to its detailed sedimentary record dated 50,000 to 28,000 cal BP. Identifying the natural environments of the Middle to Upper Palaeolithic (MUP) transition is necessary to understand the settlement strategies and related behaviour of both Neanderthals and Anatomically Modern Humans, both of whom may have occupied the region at the same time. A multidisciplinary excavation was carried out between 2011 and 2016. Detailed analyses of the sediments, vertebrate microfauna, pollen and charcoal revealed minor but observable fluctuations in climate, with little change in the surrounding vegetation. The Pod Hradem palaeoenvironmental dataset is complex, but generally reflects a predominantly glacial climate with a range of vegetation types and habitats during the Late Pleistocene, followed by the warmer and more humid Holocene. The MUP transition as recorded in Pod Hradem Cave was a glacial environment interrupted by two relatively warmer periods. Central Europe experienced extreme climate fluctuations during MIS3, as recorded from different sedimentary archives, but it seems that the Pod Hradem Cave environment may have acted as a buffer zone, ameliorating those extremes, and providing a suitable refuge for both bears seeking winter hibernation dens and occasionally visiting humans.

Pod Hradem Cave, located in the Moravian Karst, Czech Republic, offers an excellent opportunity for environmental reconstructions of Marine Isotope Stage 3 (MIS 3) in Central Europe due to its detailed sedimentary record dated 50,000 to 28,000 cal BP. Identifying the natural environments of the Middle to Upper Palaeolithic (MUP) transition is necessary to understand the settlement strategies and related behaviour of both Neanderthals and Anatomically Modern Humans, both of whom may have occupied the region at the same time. A multidisciplinary excavation was carried out between 2011 and 2016. Detailed analyses of the sediments, vertebrate microfauna, pollen and charcoal revealed minor but observable fluctuations in climate, with little change in the surrounding vegetation. The Pod Hradem palaeoenvironmental dataset is complex, but generally reflects a predominantly glacial climate with a range of vegetation types and habitats during the Late Pleistocene, followed by the warmer and more humid Holocene. The MUP transition as recorded in Pod Hradem Cave was a glacial environment interrupted by two relatively warmer periods. Central Europe experienced extreme climate fluctuations during MIS3, as recorded from different sedimentary archives, but it seems that the Pod Hradem Cave environment may have acted as a buffer zone, ameliorating those extremes, and providing a suitable refuge for both bears seeking winter hibernation dens and occasionally visiting humans.

Two groundwater bodies, Grazer Feld and Leibnitzer Feld, with surface areas of 166 and 103 km2 respectively are characterised for the first time by measuring the combination of δ18O/δ2H, 3H/3He, 85Kr, CFC-11, CFC-12 and hydrochemistry in 34 monitoring wells in 2009/2010. The timescales of groundwater recharge have been characterised by 131 δ18O measurements of well and surface water sampled on a seasonal basis. Most monitoring wells show a seasonal variation or indicate variable contributions of the main river Mur (0–30%, max. 70%) and/or other rivers having their recharge areas in higher altitudes. Combined δ18O/δ2H-measurements indicate that 65–75% of groundwater recharge in the unusual wet year of 2009 was from precipitation in the summer based on values from the Graz meteorological station. Monitoring wells downstream of gravel pit lakes show a clear evaporation trend. A boron–nitrate differentiation plot shows more frequent boron-rich water in the more urbanised Grazer Feld and more frequent nitrate-rich water in the more agricultural used Leibnitzer Feld indicating that a some of the nitrate load in the Grazer Feld comes from urban sewer water. Several lumped parameter models based on tritium input data from Graz and monthly data from the river Mur (Spielfeld) since 1977 yield a Mean Residence Time (MRT) for the Mur-water itself between 3 and 4 years in this area. Data from δ18O, 3H/3He measurements at the Wagna lysimeter station supports the conclusion that 90% of the groundwaters in the Grazer Feld and 73% in the Leibnitzer Feld have MRTs of <5 years. Only in a few groundwaters were MRTs of 6–10 or 11–25 years as a result of either a long-distance water inflow in the basins or due to longer flow path in somewhat deeper wells (>20 m) with relative thicker unsaturated zones. The young MRT of groundwater from two monitoring wells in the Leibnitzer Feld was confirmed by 85Kr-measurements. Most CFC-11 and CFC-12 concentrations in the groundwater exceed the equili

Neutron radiation as a non-ionizing radiation is particularly difficult to detect; therefore a conversion material is required. The conversion material converts neutrons into secondary charged particles in order for them to be detected in a silicon detector. The use of titanium diboride (TiB 2) as the conversion material deposited by an electron beam-physical vapour deposition (EB-PVD) as a part of a front-side contact of a planar silicon detector is presented. The effect of different front-side contact material compositions is discussed. The detectors behaviour was examined using alpha particles and thermal neutrons from an 241Am-Be source. Simultaneously, a Geant4 simulation was so as executed to evaluate the conversion layer functionality and to discover the conversion material thickness for the best neutron detection efficiency. © 2012 IOP Publishing Ltd and SISSA.