Estanislao Pujades

Emerging organic contaminants in groundwater in Spain: A review of sources, recent occurrence and fate in a European context

This paper reviewed the presence of emerging organic contaminants (EOCs) that have been found in the groundwater in Spain in both, rural and urban areas. The list of compounds included pesticides, pharmaceutical active compounds (PhACs), selected industrial compounds, drugs of abuse (DAs), estrogens, personal care products and life-style compounds. The main sources of pollution and possible pathways have been summarised in this review. EOCs are likely to enter to the aquifer mainly through the effluents of waste water treatment plants (WWTPs) and are present in groundwater at concentrations of ng/L to μg/L. The most studied compounds in Spanish groundwater were pesticides followed by industrial compounds and PhACs. It is important to mention that compared to other water bodies, such as rivers, groundwater is considerably less contaminated, which may be indicative of the natural attenuation capacity of the aquifers. However, some EOCs have sometimes been detected at higher concentration levels in the aquifer than in the rivers, indicating the need for further research to understand their behaviour in the aquifers. For a wide array of compounds, their maximum concentrations show values above the European groundwater quality standard for individual pesticides (0.1 μg/L). Therefore, to preserve groundwater quality against deterioration it is necessary to define environmental groundwater thresholds for the non-regulated compounds.

Urban groundwater contamination by residues of UV filters

The occurrence and fate of UV filters (UV F) in an urban aquifer in correlation with (1) the spatial distribution of UV F in Barcelonas groundwater, (2) the depth of the groundwater sample, (3) the physicochemical properties of the target compounds, (4) the recharge sources, and (5) the redox conditions of the Barcelona aquifers, were studied for the first time. The highest groundwater concentrations and the largest number of detected UV F were observed in an aquifer recharged by a polluted river (around 55 ng/L in SAP-4). In contrast, the urbanized areas had lower concentrations (around 20 ng/L in MPSP-1). Two pathways can be identified for UV F to enter the aquifers: (1) leakage of row sewage from the sewage network in urbanized areas and (2) wastewater treatment plant (WWTP) effluents discharged into the river. Measured concentrations of UV F were significantly much lower than those estimated from the waste water proportion in groundwater samples suggesting that UV F might undergo transformation processes in both reducing and oxidizing conditions.

Drugs of abuse in urban groundwater. A case study: Barcelona

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 Barcelonas 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.

Occurrence of carbamazepine and five metabolites in an urban aquifer

This paper deals with urban groundwater contaminated with carbamazepine (CBZ) and five of its human metabolites in Barcelona. Groundwater samples were accordingly collected in the aquifers of Poble Sec and Besòs River Delta. Higher concentrations and more compounds were found in the Besòs River Delta aquifer, which is recharged by a river contaminated with treated effluent from numerous treatment plants. By contrast, the urban area of Poble Sec presented lower concentrations and fewer compounds. The results showed that CBZ could be attenuated in the Poble Sec aquifer since concentrations in groundwater were lower than those evaluated from mixing of the recharge sources. Conversely, CBZ and its human metabolites were not removed under the reducing conditions of the Besòs River Delta aquifer probably because of the short residence time in this aquifer.

Occurrence, fate and risk assessment of personal care products in river–groundwater interface

This work presents the occurrence and fate of selected personal care products (PCPs) in the urban river-groundwater interface. To this end, urban river and groundwater samples were collected in Sant Adrià del Besòs (NE of Spain) and a total of 16 PCPs were analyzed including benzophenone derivatives, camphor derivatives, p-aminobenzoic acid derivatives, triazoles and parabens in three different campaigns (from May 2010 to July 2014). These compounds reach the aquifer through the recharge of Besòs River that receives large amounts of effluents from waste water treatment plants. Results have shown that most of the compounds were not or barely detected (maximum concentrations around 200ng/L) in groundwater samples during the different sampling campaigns. Only two triazoles, namely benzotriazole (BZT) and methyl benzotriazol (MeBZT) were found at high concentrations in groundwater samples (maximum concentration around 2000ng/L). The fate of PCPs in the aquifer was assessed using mixing analysis considering the seasonal variability of the Besòs River. Overall, measured groundwater concentrations were significantly much lower than those estimated by the mixing of the river water. This observation suggested that most of the PCPs are naturally removed when river water infiltrates the aquifer. However, some compounds were more persistent in the aquifer. These compounds were in descending order: the triazoles BZT and MeBZT followed by the camphor derivative 4MBC and the paraben MePB. The measured concentrations allowed us to assess the environmental risk posed by the selected UV-filters and parabens in the river and groundwater samples. Hazard Quotients (HQs) for different aquatic species were calculated in order to characterize the ecotoxicity potential of the studied compounds in the river-groundwater interface. HQ values were always below 1 indicating that at the concentrations observed in the surface or aquifer water of Besòs River these compounds pose no risk to the selected aquatic organisms.

Underground pumped storage hydroelectricity using abandoned works (deep mines or open pits) and the impact on groundwater flow

Underground pumped storage hydroelectricity (UPSH) plants using open-pit or deep mines can be used in flat regions to store the excess of electricity produced during low-demand energy periods. It is essential to consider the interaction between UPSH plants and the surrounding geological media. There has been little work on the assessment of associated groundwater flow impacts. The impacts on groundwater flow are determined numerically using a simplified numerical model which is assumed to be representative of open-pit and deep mines. The main impact consists of oscillation of the piezometric head, and its magnitude depends on the characteristics of the aquifer/geological medium, the mine and the pumping and injection intervals. If an average piezometric head is considered, it drops at early times after the start of the UPSH plant activity and then recovers progressively. The most favorable hydrogeological conditions to minimize impacts are evaluated by comparing several scenarios. The impact magnitude will be lower in geological media with low hydraulic diffusivity; however, the parameter that plays the more important role is the volume of water stored in the mine. Its variation modifies considerably the groundwater flow impacts. Finally, the problem is studied analytically and some solutions are proposed to approximate the impacts, allowing a quick screening of favorable locations for future UPSH plants.RésuméDes centrales hydroélectriques de pompage-turbinage utilisant un réservoir souterrain (UPSH Underground pumped storage hydroelectricity) constitué d’une carrière ou d’une mine profonde permettent de stocker l’excès d’électricité produite au cours des périodes de faible demande dans des régions sans relief. Il est essentiel de prendre en considération l’interaction entre les systèmes UPSH et le milieu géologique encaissant. Peu de travail existe concernant l’évaluation des impacts induits sur les écoulements d’eaux souterraines. Ceux-ci sont déterminés numériquement à l’aide d’un modèle numérique simplifié pour lequel on fait l’hypothèse qu’il est représentatif de considérer un puits ouvert de large diamètre. Le principal impact est une oscillation du niveau piézométrique dont l’amplitude dépend des caractéristiques de l’aquifère/milieu géologique, de la mine et des cycles de pompage et d’injection. Si un niveau piézométrique moyen est considéré, celui-ci diminue au début de la mise en activité du système UPSH et puis revient progressivement à son état initial. Les conditions hydrogéologiques les plus favorables pour minimiser les impacts ont été évaluées en comparant plusieurs scénarios. Comme attendu, l’amplitude de l’impact sera la plus faible dans un milieu géologique de faible diffusivité hydraulique. Cependant, le paramètre qui joue le rôle le plus important est le volume d’eau stocké dans la mine. Sa variation modifie de manière considérable les impacts sur les écoulements d’eaux souterraines. Finalement, le problème est étudié de manière analytique et des solutions sont proposées pour évaluer les impacts, permettant un premier tri rapide des sites favorables pour implanter de futures installations UPSH.ResumenLas centrales hidroeléctricas reversibles utilizando un embalse subterráneo (UPSH Underground Pumped Storage Hydroelectricity) formado por una mina a cielo abierto o subterránea permiten almacenar el exceso de electricidad producida durante períodos de baja demanda en regiones llanas. Es esencial tener en cuenta la interacción entre los sistemas UPSH y el medio geológico circundante. Existen pocos trabajos acerca de la evaluación de los impactos sobre el agua subterránea. Estos son determinados numéricamente utilizando un modelo simplificado que se supone representativo de minas subterráneas y a cielo abierto. El principal impacto consiste en la oscilación del nivel piezométrico, y su magnitud depende de las características del acuífero/medio geológico, la mina y los intervalos de bombeo e inyección. Si se considera un nivel piezométrico promedio, este decrece al inicio de la actividad del sistema UPSH y luego recupera progresivamente hasta su estado inicial. Las condiciones hidrogeológicas más favorables para minimizar los impactos son evaluadas comparando varios escenarios. La magnitud del impacto será menor en medios geológicos con baja difusividad hidráulica. Sin embargo, el volumen de agua almacenada en la mina es el parámetro que desempeña el papel más importante. Su variación modifica considerablemente los impactos sobre el flujo de agua subterránea. Por último, el problema se estudia analíticamente y se proponen algunas soluciones para evaluar los impactos. Estas soluciones permiten seleccionar rápidamente los sitios favorables para la construcción de futuras instalaciones UPSH.摘要在平坦地区可以利用露天矿坑或深矿井建造地下抽水蓄能电站,储存能源需求低的时期多余的电。充分考虑地下抽水蓄能电站和周围地质介质的相互作用必不可少。过去几乎没有对相关的地下水流影响做过评价。利用一个假定能够代表露天矿坑和深矿井的简化数值模型确定了对地下水流的影响。主要影响包括测压水头的振荡,其幅度取决于含水层/地质介质的特征、矿井和抽水注水的间隔。如果考虑平均测压水头,测压水头在地下抽水蓄能电站运行开始后初期下降,然后逐渐恢复。通过比较不同的几个方案,评价了使影响达到最小的最有利水文地质条件。水利扩散系数低的地质介质影响幅度较低。然而,发挥重要作用的参数是矿井储存水量。其变化可大大更改对地下水流的影响。最后,分析研究了出现的问题,提出了粗略估算影响的解决方法,可使人们对未来的地下抽水蓄能电站有利位置做出快速筛选.ResumoUsinas hidrelétricas reversíveis subterrâneas (UHRS) utilizando minas a céu aberto ou minas subterrâneas podem ser utilizadas em regiões planas para armazenamento do excedente da energia elétrica produzida durante períodos de baixa demanda energética. É essencial considerar a interação entre as UHRS e o meio geológico do entorno. Poucos estudos têm sido realizados na avaliação dos impactos associados ao fluxo das águas subterrâneas. Os impactos no fluxo das águas subterrâneas são determinados numericamente utilizando modelos numéricos simplificados, considerados representativos para minas a céu aberto e minas subterrâneas. Os principais impactos consistem na oscilação do nível piezométrico, e sua magnitude depende das características do aquífero/meio geológico, da mina e dos intervalos de bombeamento e injeção. Assumindo um nível piezométrico médio, há um declínio que sucede o início das atividades da UHRS, seguido de uma recuperação progressiva. As condições hidrogeológicas mais favoráveis para minimizar os impactos são avaliadas através da comparação de diversos cenários. A magnitude do impacto será inferior em meios geológicos de baixa difusividade hidráulica. Entretanto, o parâmetro que desempenha o papel mais importante é o volume da água armazenada na mina. Sua variação modifica consideravelmente os impactos no fluxo das águas subterrâneas. Por fim, o problema é estudado analiticamente e algumas soluções são propostas para aproximar os impactos, permitindo a rápida triagem de locais favoráveis para futuras UHRS.

Quantifying chemical reactions by using mixing analysis.

This work is motivated by a sound understanding of the chemical processes that affect the organic pollutants in an urban aquifer. We propose an approach to quantify such processes using mixing calculations. The methodology consists of the following steps: (1) identification of the recharge sources (end-members) and selection of the species (conservative and non-conservative) to be used, (2) identification of the chemical processes and (3) evaluation of mixing ratios including the chemical processes. This methodology has been applied in the Besòs River Delta (NE Barcelona, Spain), where the River Besòs is the main aquifer recharge source. A total number of 51 groundwater samples were collected from July 2007 to May 2010 during four field campaigns. Three river end-members were necessary to explain the temporal variability of the River Besòs: one river end-member is from the wet periods (W1) and two are from dry periods (D1 and D2). This methodology has proved to be useful not only to compute the mixing ratios but also to quantify processes such as calcite and magnesite dissolution, aerobic respiration and denitrification undergone at each observation point.

Occurrence of greenhouse gases in the aquifers of the Walloon Region (Belgium)

This work aims to (1) identify the most conductive conditions for the generation of greenhouses gases (GHGs) in groundwater (e.g., hydrogeological contexts and geochemical processes) and (2) evaluate the indirect emissions of GHGs from groundwater at a regional scale in Wallonia (Belgium). To this end, nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2) concentrations and the stable isotopes of nitrate (NO3-) and sulphate were monitored in 12 aquifers of the Walloon Region (Belgium). The concentrations of GHGs range from 0.05μg/L to 1631.2μg/L for N2O, 0μg/L to 17.1μg/L for CH4, and 1769 to 100,514ppm for the partial pressure of CO2 (pCO2). The highest average concentrations of N2O and pCO2 are found in a chalky aquifer. The coupled use of statistical techniques and stable isotopes is a useful approach to identify the geochemical conditions that control the occurrence of GHGs in the aquifers of the Walloon Region. The accumulation of N2O is most likely due to nitrification (high concentrations of dissolved oxygen and NO3- and null concentrations of ammonium) and, to a lesser extent, initial denitrification in a few sampling locations (medium concentrations of dissolved oxygen and NO3-). The oxic character found in groundwater is not prone to the accumulation of CH4 in Walloon aquifers. Nevertheless, groundwater is oversaturated with GHGs with respect to atmospheric equilibrium (especially for N2O and pCO2); the fluxes of N2O (0.32kgN2O-NHa-1y-1) and CO2 (27kgCO2Ha-1y-1) from groundwater are much lower than the direct emissions of N2O from agricultural soils and fossil-fuel-related CO2 emissions. Thus, indirect GHG emissions from the aquifers of the Walloon Region are likely to be a minor contributor to atmospheric GHG emissions, but their quantification would help to better constrain the nitrogen and carbon budgets.

Potential uses of pumped urban groundwater: a case study in Sant Adrià del Besòs (Spain)

Urban groundwater has often been over-exploited for industrial uses. Now, this usage tends to be reduced or the resource abandoned due to pollution and/or changes in land use. The use and the subsequent disuse of groundwater has resulted in rising water tables that damage underground structures (e.g., building basements and underground car parks and tunnels), leading to the need for additional pumping in urban areas. In the case of the underground parking lot of Sant Adrià del Besòs (Barcelona, NE Spain), large amounts of urban groundwater are pumped to avoid seepage problems. Can this pumped groundwater be used for other purposes (e.g., drinking water and urban irrigation) instead of wasting this valuable resource? To answer this question, it was necessary to quantify the groundwater recharge and to assess the evolution of groundwater quality. The limiting factor at this study site is the groundwater quality because ammonium and some metals (iron and manganese) are present at high concentrations. Hence, further treatment would be needed to meet drinking water requirements. The pumped groundwater could also be used for supplementing river flow for ecological benefit and/or for mitigating seawater intrusion problems. Currently, only a small amount of this urban groundwater is used for cleaning public areas and watering public gardens. This situation highlighted the urgent need to manage this resource in a responsible and more efficient manner, especially in moments of high water demand such as drought periods.RésuméLes eaux souterraines en milieu urbain ont souvent été surexploitées pour des usages industriels. Désormais, cet usage tend à se réduire ou la ressource est abandonnée en raison de pollutions et/ou de changements d’occupation des sols. La réduction de l’usage des eaux souterraines a conduit à une augmentation des niveaux d’eau avec des dommages sur les structures souterraines (par ex. fondations de bâtiments et de parkings souterrains et tunnels), conduisant à un besoin de pompages supplémentaires dans les zones urbaines. Dans le cas du parking souterrain de Sant Adrià del Besòs (Barcelone, Nord-est de l’Espagne), des quantités importantes d’eau souterraine sont pompées pour éviter des problèmes d’infiltration d’eau. Est-ce que cette eau souterraine pompée peut être utilisée pour d’autres besoins (ex. eau de boisson et arrosage des espaces verts), au lieu de gaspiller cette ressource de valeur ? Pour répondre à cette question, il était nécessaire de quantifier la recharge de l’aquifère et d’évaluer l’évolution de la qualité de l’eau souterraine. Le facteur limitant de ce site d’étude est la qualité de l’eau souterraine en raison de la présence d’ammonium et de certains métaux (fer et manganèse) à des concentrations élevées. Par conséquent, un traitement complémentaire serait nécessaire pour atteindre les exigences d’une eau de boisson. L’eau souterraine pompée pourrait aussi être utilisée afin de soutenir le débit de la rivière, pour un bénéfice écologique et/ou pour atténuer les problèmes d’intrusions d’eau de mer. Actuellement, seule une petite part de cette eau souterraine urbaine est utilisée pour le nettoyage des espaces publics et pour l’arrosage des espaces verts. Cette situation souligne le besoin urgent de gérer cette ressource de manière responsable et plus efficace, en particulier lors des périodes de sécheresse où la demande en eau est forte.ResumenA menudo, las aguas subterráneas urbanas han sido sobreexplotadas para usos industriales. Debido a la contaminación o a cambios urbanísticos, el uso de estos recursos tiende a reducirse o incluso a abandonarse. El cese del aprovechamiento de las aguas subterráneas en zonas urbanas suele ocasionar la recuperación de los niveles freáticos, lo que puede afectar a estructuras subterráneas (por ejemplo: sótanos de edificios, aparcamientos subterráneos y túneles). Esta recuperación de los niveles freáticos puede conllevar bombeos adicionales. En el caso del aparcamiento subterráneo de Sant Adrià del Besòs (Barcelona, NE de España), se bombean grandes cantidades de agua subterránea para evitar problemas de filtraciones. ¿Se puede usar este recurso para otros usos (por ejemplo, agua potable y riego urbano) en vez de desperdiciarse? Para responder a esta pregunta, fue necesario cuantificar la recarga y evaluar la evolución de la calidad de estos acuíferos. En este caso, el factor limitante es la calidad del agua subterránea debido a que el amonio y algunos metales (hierro y manganeso) están presentes en altas concentraciones. En este caso, se necesitaría de un tratamiento adicional para poder satisfacer los requerimientos de calidad para agua potable. El agua bombeada también podría usarse para complementar el caudal ecológico del río y/o para mitigar problemas de intrusión marina en las proximidades de la zona. Actualmente, sólo una pequeña cantidad de esta agua subterránea urbana se utiliza para limpieza urbana y riego de jardines públicos. Esta situación puso de manifiesto la necesidad urgente de gestionar este recurso de manera responsable y más eficiente, especialmente en momentos de alta demanda de agua como los períodos de sequía.摘要城市地下水常常超采用于工业。现在,由于污染及/或土地利用的变化,这种用途趋向于减少或资源被放弃。地下水的使用及随后的停止使用致使水位上升,损害了地下结构(例如建筑物基础及地下停车场和隧道),导致需要城区额外抽水。在(西班牙巴塞罗那)Sant Adrià del Besòs一个地下停车场的实例中,大量地下水被抽取以避免渗漏问题。这些抽取的地下水能否用于其它目的而不浪费这个宝贵的资源?为了回答这个问题,有必要量化地下水补给量并评价地下水水质的演化。本研究场地的限制因素是地下水水质,因为水中铵和一些金属(铁和锰)的含量很高。因此,需要进一步处理以满足饮用水要求。抽取的地下水还可用于补充河流获取生态效益以及/或减轻海水入侵问题。目前,只有一小部分这种城市地下水用于清洁公共区域及浇灌公共花园。这种情况强调了以负责任及更高效的方式管理此种资源的迫切需要,特别是在干旱期水需求很大的时候更是如此。ResumoMuitas vezes, as águas subterrâneas urbanas foram sobrexplotadas para fins industriais. Agora, esse uso tende a ser reduzido ou o recurso abandonado devido à poluição e/ou mudanças no uso da terra. A utilização e o subsequente desuso das águas subterrâneas resultaram na elevação do nível das águas subterrâneas que danificam estruturas subterrâneas (p. ex., porões de construção, estacionamentos subterrâneos e túneis), levando à necessidade de bombeamento adicional em áreas urbanas. No caso do estacionamento subterrâneo de Sant Adrià del Besòs (Barcelona, NE, Espanha), grandes quantidades de águas subterrâneas urbanas são bombeadas para evitar problemas de infiltração. Pode esta água subterrânea bombeada ser usada para outros fins (p. ex., água potável e irrigação urbana) em vez de se desperdiçar este valioso recurso? Para responder a essa pergunta, foi necessário quantificar a recarga das águas subterrâneas e avaliar a evolução da qualidade das águas subterrâneas. O fator limitante neste local de estudo é a qualidade das águas subterrâneas, porque a amônia e alguns metais (ferro e manganês) estão presentes em altas concentrações. Por conseguinte, seria necessário um tratamento posterior para atender aos requisitos de água potável. As águas subterrâneas bombeadas também poderiam ser usadas para suplementar o fluxo do rio para benefício ecológico e/ou para mitigar problemas de intrusão de água do mar. Atualmente, apenas uma pequena quantidade destas águas subterrâneas urbanas é usada para limpar áreas públicas e regar jardins públicos. Esta situação realçou a necessidade urgente de gerir este recurso de forma responsável e mais eficiente, especialmente em momentos de alta demanda de água, como os períodos de seca.