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Due to the current analytical processes that are not able to measure all the pharmaceutical molecules and to the high costs and the consumption of time to sample and analyze PhACs, models to calculate Predicted Environmental Concentrations (PECs) have been developed. However a comparison between MECs and PECs, taking into account the methods of calculations and peculiarly the parameters included in the calculation (consumption data, pharmacokinetic parameters, elimination rate in STPs and in the environment), is necessary to assess the validity of PECs. MEC variations of sixteen target PhACs [acetaminophen (ACE), amlodipine (AML), atenolol (ATE), caffeine (CAF), carbamazepine (CAR), doxycycline (DOX), epoxycarbamazepine (EPO), fluvoxamine (FLU), furosemide (FUR), hydrochlorothiazide (HYD), ifosfamide (IFO), losartan (LOS), pravastatin (PRA), progesterone (PROG), ramipril (RAM), trimetazidine (TRI)] have been evaluated during one hydrological cycle, from October 2011 to October 2012 and compared to PECs calculated by using an adaptation of the models proposed by Heberer and Feldmann (2005) and EMEA (2006). Comparison of PECs and MECS has been achieved for six molecules: ATE, CAR, DOX, FUR, HYD and PRA. DOX, FUR and HYD present differences between PECs and MECs on an annual basis but their temporal evolutions follow the same trends. PEC evaluation for these PhACs could then be possible but need some adjustments of consumption patterns, pharmacokinetic parameters and/or mechanisms of (bio)degradation. ATE, CAR and PRA are well modeled; PECs can then be used as reliable estimation of concentrations without any reserve. [ABSTRACT FROM AUTHOR]

Summary: Hydrochemical and stable isotopic (2H, 18O) data were used to characterize the groundwater flow and major chemical features within a complex fractured volcanic aquifer system, the Argnat basin, which is located in the Chaîne des Puys (French Massif Central). From 10 sampling points, the study of the transfer into the saturated zone from upstream to downstream, given the geological context and topography, allows to estimate the role of supply from high and low altitudes to the recharge processes. This work shows the existence of different types of supply between pahoehoe and a’a flows. Therefore, the morphology of volcanic flows impacts the chemical and isotopic signatures of groundwater, enhancing or reducing the influence of the unsaturated zone on the pathways of infiltrated water. Pahoehoe flows imply horizontal water flows of low discharge at the top of the lava whereas a’a flows seems to be much more heterogeneous and locally able to promote the existence of perched water bodies and further vertical circulations. Taking into account these two types of behaviour, a conceptual scheme of the functioning of this heterogeneous environment is proposed, which will help towards a sustainable management of volcanic aquifers in relation with the . [ABSTRACT FROM AUTHOR]

Abstract: The Lorraine Triassic Sandstone Aquifer (LTSA), which has already been the subject of a chemical and radioisotopic study (1979), is used to investigate the impacts of 20a of large scale pumping on baseline water quality. In parallel, new sampling of the aquifer (2001) provides new inorganic geochemical data (including trace elements) that allow improving the knowledge of baseline conditions and hydrochemical functioning of a major sandstone aquifer. The good correlation between 14C activities, temperature and depth along the main flow line indicate regular downgradient trends and possible water stratification. Unreactive tracers, mainly stable isotope ratios 18O and 2H, as well as C isotopes are used to define a timescale for the aquifer, showing two groups of groundwater, namely of modern and Holocene age, and late Pleistocene age, with a mixing zone. Baseline quality is then represented by a wide range of concentrations, mainly the result of time-dependent water–rock interaction, as already observed elsewhere in Triassic sandstone aquifers. Some trace elements such as Li, Rb, Cs, which are not limited by solubility constraints, show linear trends. During saturated flow downgradient, the chemistry is also specifically characterised by a regular increase in Na and Cl (and locally SO4) as a result of evaporite dissolution related to overlying or basement limits. The aquifer is mostly oxidising with a redox boundary marked by U decrease, some 40km from outcrop. Groundwater abstraction since the 1970s has created a strong lowering (10–150m) of the water table, especially from 1970 to 1980. Based on nine boreholes, previously sampled in 1979, a decreasing evolution in radiocarbon content of the TDIC, together with significant evolution of 18O content, indicate that old groundwater has moved upgradient. The major difference in terms of baseline evolution is observed using Cl and Na concentration and, locally, SO4, indicating an increasing influence of water circulation involving overlying or basement formations, or of mixing with Permian waters. From the point of view of aquifer management, the perceptible NO3 increase could provide information on the progress of any contamination under the aerobic conditions. In addition, the few key elements, indicators of disequilibrium, related to overlying or deep waters, should be included in regular monitoring programmes. [Copyright &y& Elsevier]

Abstract: In order to investigate the role of local contribution versus long-range transport in the rainwater chemistry at a site in the North-western Mediterranean area, we collected 90 daily wet samples, 75 dry samples (corresponding to bulk sampling during dry periods) and 102 sequential wet sub-samples from October 1997 to March 1999. Major ions were analyzed (Mg2+, Ca2+, Na+, K+, Cl−, SO4 2−, NO3 −, NH4 +, HCO3 −) along with the determination of pH and electrical conductivity. To discriminate the fraction of components supplied by long- and medium-range transport from that derived from local scavenging, a classification of precipitation chemistry according to air masses back trajectories and sources has been established. Three different origins were identified: (1) a Western one associated with high amount of rainfall and an equivalent contribution of terrestrial, marine and anthropogenic components, (2) a Northern and North-eastern origin characterized by low rainfall heights and a high load in anthropogenic and terrestrial components, (3) a Southern origin which presented the highest concentration in sea-salt components and a high participation of anthropogenic components. Determination of the local contribution has been achieved through the characterization of dry deposition rates and the investigation of the evolution of rain chemistry during events. As only 21 to 32% of the total concentration is removed in the first fraction, it appeared that the below-cloud scavenging process does not dominate the removal of atmospheric components in the region. The evolution of the rain chemistry during an event is perturbed by increases of concentrations that could be due either to long-range inputs (of humid air parcels coming from the near Mediterranean Sea or occurrence of Saharan dust) or to the scavenging of local sources of pollutants and terrestrial material. [Copyright &y& Elsevier]

From March 1997 to March 1999, sequential rainwater samples were collected during 12 rainfalls at Avignon, Southern France, with the objective of investigating how the formation conditions affect the isotopic composition of the most frequent rain types occurring in the western Mediterranean region. Three major isotopic trends were identified: (i) a descending δ18O trend, produced when a cold front penetration causes the rise of warm and humid air masses, accompanied by adiabatic cooling and precipitation. The temperature variation is the predominant feature of frontal rainfalls; (ii) an L-shaped δ18O trend, which can be produced by convective rains, with an initial rapid decrease followed by a stationary value; (iii) a V-shaped trend, in which the final phase of precipitation obeys a different mechanism from the first phase. Frontal and convective rainfalls may produce this trend.Three heavy rainfalls were selected for applying a numerical Rayleigh condensation model to describe their isotopic trends. Some irregularities in the generally monotonously decreasing isotopic trend were attributed to inputs of new air masses, which were often recorded by chemical variations as well. The numerical model indicates that about 80, 60 and 45% of the vapour initially present was condensed. The lowest fraction corresponds to the most abundant rainfall, and it is due to the convective nature of the latter implying a continuous supply of condensable vapour. [Copyright &y& Elsevier]

Climatic instability during the late Pleistocene has been reflected in the pattern of groundwater recharge. This report summarizes palaeoclimate knowledge during the late Weichselian in Europe. During this period the majority of northern Europe was covered by thick ice sheets and permafrost, preventing aquifers from recharging. In contrast, southern Europe was generally free of these palaeoclimatic features. Palaeoclimatic information has been combined with isotope data to better understand the palaeorecharge conditions and recharge timing across the European continent. The O and H relationship shows latitudinal plus climatic influences. Radiocarbon data show that while southern European aquifers have generally been recharged continuously during the last 40,000 years, northern European aquifers typically show a recharge gap during the Last Glacial Maximum. Areas that underwent continuous recharge during the entire late Pleistocene period can also be distinguished from areas where recharge to aquifers was prevented during the Last Glacial Maximum. Finally, several examples are presented of melt-water recharge or subglacial recharge. The identification of such diversity in the groundwater palaeorecharge in Europe is of great importance for modellers developing management schemes for groundwater resources. [ABSTRACT FROM AUTHOR]

Summary: The study was carried out in the northern part of the Aquitaine Basin extending in Southwest France. The basin has been intensively exploited for various purposes for many years. Although the geological context is well known, there are still some gaps in the knowledge about the hydrogeochemical regime, groundwater average residence time and the palaeohydrological conditions prevailing during the recharge period which would help to secure sustainable exploitation of the resources. Environmental isotopes (18O, 2H, 3H, 13C) together with radiocarbon were used to evaluate hydrochemical evolution, residence time and palaeorecharge conditions for Jurassic, Cretaceous and Eocene aquifers. Radiocarbon activity in the aquifers varies widely between 0 and 94pmc. After radiocarbon corrections the ages indicate both modern and old waters sometimes exceeding the limit for 14C dating. The Fontes and Garnier model is best adapted to the specificity of the carbonate system. The content in stable isotopes of water is varying between −7.7‰ and −4.9‰ for δ18O and −52.3‰ to −29.6‰ for δ2H. The wide ranges of stable isotopic values imply variable climatic conditions. A group of isotopically depleted samples was detected, indicating colder climatic conditions during the recharge. Radiocarbon ages calculation, together with isotopic signature, point out that the depletion in stable isotopic values fits the period between 20 and 15ka B.P. and therefore indicate the Last Glacial Maximum (LGM). According to the correction model, the transition from Pleistocene to Holocene would occur between 15 and 12ka B.P. Palaeohydrological data from the Northern Aquitaine Basin does not confirm a significant hiatus in the recharge history. The recharge conditions in South Europe seem to have occurred under discontinuous permafrost conditions as documented by many palaeoclimatological archives. This is in favour of an uninterrupted recharge of the confined aquifers of Northern Aquitaine Basin. Such information should be considered by modellers in their attempts to simulate the hydrogeological functioning of large confined aquifers on the very long time range. [Copyright &y& Elsevier]

Holocene paleoclimatic patterns in NE Brazil are recognized to present singular characteristics when compared with the remaining tropical South-America. In particular, isotopic variations in speleothem calcite highlight that in contrast to the rest of tropical SA , NE Brazil experienced humid conditions during lower summer insolation, i.e. throughout the Early-Mid Holocene, and aridity when, as nowadays, summer insolation was high. In parallel, paleobotanical and palynological investigations suggest that these wetter conditions, also associated with colder climate, could have promoted the setting of ecological corridors between the current Amazonian (continental) and Atlantic (littoral) forests. In this context, this work aims at showing how groundwater isotopic data could be used as a complementary proxy to further explain these Holocene paleohydroclimatic and paleoecologic processes. By comparing δ 18 O, δ 2 H and d-excess of modern waters with Early-Mid Holocene groundwater in Recife (Pernambuco state, NE Brazil), differences in recharge patterns and moisture origin can be constrained. We find that Early-Mid Holocene waters present higher d-excess than the modern groundwater. Given that the Early-mid Holocene colder and wetter conditions (higher relative humidity) should lead to a reverse trend, i.e. lower d-excess, we hypothesize that the groundwater moisture sources was heavily recycled. Such a hypothesis would be consistent with the presence of a rainforest-type ecosystem, similar to the present Amazonian forest, in the currently arid NE Brazil. These observations highlight the potential added value of the groundwater isotopes proxy to discuss the interrelationships of paleohydrological and paleoecological patterns during the Early-Mid Holocene. These new proxies might allow the spatio-temporal extent of the above-mentioned ecological corridors to be discussed. [ABSTRACT FROM AUTHOR]

Abstract: The Bohemian Cretaceous Basin represents a complex hydrogeological system composed of several aquifers with very favourable hydrogeological properties. These aquifers have been exploited for many years. The sustainability of such resources might be guaranteed by well organised water management, which requires a detailed knowledge about the functioning of the hydrogeological system. Although many efforts have previously been made to evaluate groundwater residence time, the many intricate geochemical processes complicate groundwater dating. The current study clarifies the functioning of this complex hydrogeological basin using hydrogeochemical and isotopic investigations. Chemical data and a combination of 13C and 14C isotopes within the Cenomanian and the Turonian layers indicate groundwater interactions with deep-seated CO2, rock matrix, surface waters and fossil organic matter. Very depleted δ13C values (average δ13C∼−13.4‰) suggest interactions with fossil organic matter, whereas enriched values account for the interaction with deep CO2 gas ascending from the upper mantle via the numerous faults and fractures, and also, to a lesser extent, from calcite dissolution. Geochemical processes that take place in the system cause a clear depletion in 14C that greatly complicates groundwater residence time evaluation. Different dilution correction models have been applied considering the different C origins. The stable isotope content, mainly 18O values, indicates both the contribution of modern precipitation and the partial infiltration of palaeowaters during colder climatic conditions from the end of the Pleistocene. The apparent 14C groundwater ages range from modern to 11.1ka BP, which suggests some post glacial infiltration from melting ice sheets. Finally, all the acquired information was used to propose a conceptual model of C origin within the basin. [Copyright &y& Elsevier]