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Jurado A.,CSIC - Institute of Environmental Assessment And Water Research | Jurado A.,Polytechnic University of Catalonia | Mastroianni N.,CSIC - Institute of Environmental Assessment And Water Research | Vazquez-Sune E.,CSIC - Institute of Environmental Assessment And Water Research | And 9 more authors.
Science of the Total Environment | Year: 2012

This study is concerned with drugs of abuse (DAs) and their metabolites in urban groundwater at field scale in relation to (1) the spatial distribution of DAs in Barcelona's groundwater, (2) the depth of the groundwater samples, (3) the presence of DAs in recharge sources, and (4) the assessment of the fate of DAs in Barcelona aquifers. To this end, 37 urban groundwater samples were collected in the city of Barcelona and a total of 21 drugs were analyzed including cocainics, amphetamine-like compounds, opioids, lysergics and cannabinoids and the prescribed drugs benzodiazepines. Overall, the highest groundwater concentrations (around 200. ng/L in SAP-4) and the largest number of detected DAs were found in zones basically recharged by a river that receives large amounts of effluents from waste water treatment plants (WWTPs). In contrast, the urbanized areas yielded not only lower concentrations but also a much smaller number of drugs, which suggests a local origin. In fact, cocaine and its metabolite were dominant in more prosperous neighborhoods, whereas the cheaper MDMA was the dominant DA in poorer districts. Measured concentrations were consistently smaller than those estimated from the waste water fraction in groundwater samples, suggesting that DAs undergo removal processes in both reducing and oxidizing conditions. © 2012 Elsevier B.V. Source


Jurado A.,CSIC - Institute of Environmental Assessment And Water Research | Jurado A.,Polytechnic University of Catalonia | Vazquez-Sune E.,CSIC - Institute of Environmental Assessment And Water Research | Soler A.,University of Barcelona | And 7 more authors.
Applied Geochemistry | Year: 2013

The different recharge sources and their mixing ratios were investigated in water samples from an urban aquifer. Two distinct zones from Barcelona city were compared: (1) Poble Sec and (2) Besòs River Delta, which are located in a densely populated area with a strong industrial impact. In this study 106 water samples were collected from July 2007 to May 2010 for hydrochemical and isotopic characterisation. The application of environmental isotopes coupled with hydrochemistry provided the necessary information to isotopically quantify groundwater recharge sources and evaluate the occurrence of redox processes. In the Besòs River Delta, a decrease in dissolved SO42- concentration and an increase in δ34SSO4 and δ18OSO4 values were observed in groundwater samples, both indicating SO42- reduction. Moreover, other chemical indicators supported a reducing environment, such as low or null levels of dissolved O2 and NO3-, the presence of NH4+ and an increase in dissolved Fe and As. The reducing conditions were probably induced by the organic C dissolved in water infiltrating from the River Besòs. In Poble Sec, the relationship between δ34SSO4 and δ18OSO4 showed a strong influence of sewage water infiltration into the aquifer. However, the aquifer is oxic and there is no influence of SO42- reduction. © 2013 Elsevier Ltd. Source


Garcia-Selles C.,Geological Institute of Catalonia | Pena J.C.,Meteorological Service of Catalonia | Marti G.,Geological Institute of Catalonia | Oller P.,Geological Institute of Catalonia | Martinez P.,Geological Institute of Catalonia
Cold Regions Science and Technology | Year: 2010

Major avalanche episodes registered in the Eastern Pyrenees (north-eastern Iberian Peninsula) are correlated with both the North Atlantic Oscillation (NAO) and the Western Mediterranean Oscillation (WeMO). The NAO is one of the most important and recurrent patterns of atmospheric circulation variability in the Northern Hemisphere and affects the behaviour of surface temperatures and precipitation in Western Europe. The Western Mediterranean Oscillation index (WeMOi) controls intense precipitation in the eastern part of the Iberian Peninsula. The link between both indices and major avalanche activity is undertaken by applying a cumulative index. A link between avalanche activity and the NAO has been found in Iceland, but it has not been detected in areas closer to the Pyrenees, such as the French Alps. This paper examines the linkage to the NAO in an area further from the centres of the dipole than is the case for Iceland. Results show a significant negative correlation between major avalanche activity in the Eastern Pyrenees and both NAO index (NAOi) and WeMOi, which is even higher with the cumulative NAOi (CNI) and the cumulative WeMOi (CWI). The cumulative index reflects the cumulative effect of snow accumulation in the avalanche starting zones as precipitation is affected by the variations of NAOi and WeMOi. Consequently, the correlation is negative since it has been demonstrated that increased precipitation in the Eastern Pyrenees is linked to negative values of both low frequency patterns. Nevertheless, results from the diverse avalanche forecasting regions in the Eastern Pyrenees suggest a different response of avalanche activity to both indices, confirming the Pyrenees as a complex snow-climate boundary. Lastly, possible changes in avalanche activity in the coming decades may be suggested by the NAO evolution associated with global warming scenarios that are foreseen and the present interannual trend of the WeMOi. © 2010 Elsevier B.V. Source


Tubau I.,Polytechnic University of Catalonia | Tubau I.,Geological Institute of Catalonia | Vazquez-Sune E.,CSIC - Institute of Environmental Assessment And Water Research | Jurado A.,Polytechnic University of Catalonia | And 2 more authors.
Science of the Total Environment | Year: 2014

This study presents a methodology using an end-member mixing analysis (EMMA) and MIX to compute mixing ratios and to identify hydrochemical reactions in groundwater. The methodology consists of (1) identifying the potential sources of recharge, (2) characterising recharge sources and mixed water samples using hydrogeochemistry, (3) selecting chemical species to be used in the analysis and (4) calculating mixing ratios and identification of hydrochemical reactions in groundwater. This approach has been applied in the Besòs River Delta area, where we have collected 51 groundwater samples and a long data register of the hydrogeochemistry of the Besòs River created by the Catalan Water Agency is also available. The EMMA performed in the Besòs River suggests that 3 end-members are required to explain its temporal variability, accounting for the species chloride, sulphate, sodium, bicarbonate, calcium, magnesium, potassium, ammonium, total nitrogen, and electrical conductivity. One river end-member is from the wet periods (W1), and two are from dry periods (D1 and D2). These end-members have been used to compute mixing ratios in groundwater samples because the Besòs River is considered the main recharge source for the aquifer. Overall, dry season end-members dominated over the wet season end-member, in a proportion of 4:1. Moreover, when departures from the mixing line exist, geochemical processes might be identified. Redox processes, carbonate dissolution/precipitation and ion exchange processes may occur in Besòs Delta aquifer. © 2013 Elsevier B.V. Source


Benjumea B.,Geological Institute of Catalonia | Macau A.,Geological Institute of Catalonia | Gabas A.,Geological Institute of Catalonia | Bellmunt F.,Geological Institute of Catalonia | And 2 more authors.
Near Surface Geophysics | Year: 2011

Mapping bedrock structure beneath overburden is crucial for understanding geological and hydrogeological processes. Acquiring this information is generally done using well drilling or geophysical surveys; but these studies are expensive and require large periods of acquisition and processing time. In addition, geophysical data acquisition can be logistically challenging in urban zones with limited available areas for instrumentation deployment. Under favourable conditions (ID structure and high acoustic impedance contrast) the HTV microtremor technique can provide estimates of bedrock depth. This technique is used to obtain the soil resonance frequency in seismic microzonation studies. It is based on the computation of the horizontal to vertical spectral ratio of microtremor recordings acquired at a single station. The soil resonance frequency is related to soil shear-wave velocity and thickness. Here we investigate the capability of combining microtremor and traditional exploration geophysical techniques (electrical resistivity and seismic tomography) to obtain an empirical relationship relating soil resonance frequency and overburden thickness. Subsequently we propose to extend microtremor measurements to adjacent areas that have not been covered by geophysical surveys. This methodology has been applied at a test site located in a granitic environment where alluvial/ colluvial sediments cover the granite weathering profile. This area is characterized by urban development and sectors having rugged topography. A priori, this area has suitable conditions to apply the H/V microtremor technique. Overburden thickness has been estimated to range between 20-50 m. The proposed methodology has been validated at the test site, encouraging us to apply the H/V method as an exploration tool in similar geological environments. © 2011 European Association of Geoscientists & Engineers. Source

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