Geochemical characterisation and health concerns of mineral bottled waters in Catalonia (North-eastern Spain)

Spain currently produces around 7000 million litres of mineral water a year, of which about 20% is produced in Catalonia, and there is a need for greater regulation and research into bottled waters and their impact on human health. A total of 29 samples were analysed from different brands of commercially bottled water, and 71 chemical elements were determined in each sample. The aim was to classify each brand based on composition, compare lithological origins, verify compliance with international standards for drinking water, and report benefits for human health. More than 60% of the samples were of the calcium bicarbonate type, had a low mineral content, and were associated with granitic aquifers, ranging from leucogranites to granodiorites. In contrast, 17% were of the sodium bicarbonate type, had harder waters, and were related to thermal springs. The thermal springs of the bottled waters from the Montseny-Guilleres massif (Vichy Catalán, Malavella, and San Narciso) emerge at a temperature of 60 °C with their own natural gas. Two samples exceeded European standards for As and Hg concentrations in water for human consumption, while one showed a concentration of U greater than that set out in international recommendations

Enhanced Groundwater Protection and Management Using Gravity and Geoelectrical Data (Valls Basin, Spain)

The basis for the protection and prevention of groundwater pollution lies in the accurate assessment of vulnerability in terms of the exposure of groundwater bodies to contaminants before they are potentially discharged into the environment. The vulnerability assessment consists of calculating the ease with which pollutants can reach the aquifer from the surface through the vadose zone, which effectively reduces the pollutant load when the transit time is long. Index methods are mostly used, as they are based on input data that are readily available, easy to implement and interpret, and which are simple and practical. However, there are also limitations, as some methods are somewhat subjective and provide only a qualitative approximation. This case study aims to develop a methodology that can quantitively estimate the hydrogeological parameters of the aquifer formations of the Valls basin using geophysical methods and the Dar Zarrouk parameters. The specific treatment carried out on data from gravity stations and vertical electric soundings, supported by the available well data, allows for the delineation of the most favourable areas for the exploitation of groundwater resources (higher hydraulic transmissivity) and the areas most susceptible to pollution (with a shorter transit time) on a regional scale. Geophysical methods have proved useful, sustainably providing valuable information without the need to drill new boreholes that could act as preferential pathways for pollutants into the aquifer

Assessing the agricultural reuse of the digestate from microalgae anaerobic digestion and co-digestion with sewage sludge

Microalgae anaerobic digestion produces biogas along with a digestate that may be reused in agriculture. However, the properties of this digestate for agricultural reuse have yet to be determined. The aim of this study was to characterise digestates from different microalgae anaerobic digestion processes (i.e. digestion of untreated microalgae, thermally pretreated microalgae and thermally pretreated microalgae in co-digestion with primary sludge). The main parameters evaluated were organic matter, macronutrients and heavy metals content, hygenisation, potential phytotoxicity and organic matter stabilisation. According to the results, all microalgae digestates presented suitable organic matter and macronutrients, especially organic and ammonium nitrogen, for agricultural soils amendment. However, the thermally pretreated microalgae digestate was the least stabilised digestate in comparison with untreated microalgae and co-digestion digestates. In vivo bioassays demonstrated that the digestates did not show residual phytotoxicity when properly diluted, being the co-digestion digestate the one which presented less phytotoxicity. Heavy metals contents resulted far below the threshold established by the European legislation on sludge spreading. Moreover, low presence of E. coli was observed in all digestates. Therefore, agricultural reuse of thermally pretreated microalgae and primary sludge co-digestate through irrigation emerges a suitable strategy to recycle nutrients from wastewater

Characterization of a Shallow Coastal Aquifer in the Framework of a Subsurface Storage and Soil Aquifer Treatment Project using Electrical Resistivity Tomography (Port de la Selva, Spain)

Water percolation through infiltration ponds is creating significant synergies for the broad adoption of water reuse as an additional non-conventional water supply. Despite the apparent simplicity of the soil aquifer treatment (SAT) approaches, the complexity of site-specific hydro-geological conditions and the processes occurring at various scales require an exhaustive under-standing of the system's response. The non-saturated zone and underlying aquifers cannot be considered as a black box, nor accept its characterization from few boreholes not well distribut-ed over the area to be investigated. The electrical resistivity tomography (ERT) is a non-invasive technology, highly responsive to geological heterogeneities that has demonstrated useful to provide the detailed subsurface information required for groundwater modeling. The relation-ships between the electrical resistivity of the alluvial sediments and the bedrock and the differ-ence in salinity of groundwater, highlight the potential of geophysical methods over other more costly subsurface exploration techniques. The results of our research show that ERT coupled with implicit modeling tools provides information that can significantly help to identify aquifer geometry and characterize the saltwater intrusion of shallow alluvial aquifers. The proposed approaches could improve the reliability of groundwater models and the commitment of stakeholders to the benefits of SAT procedures

Coupled Geophysical and Hydrogeochemical Characterization of a Coastal Aquifer as Tool for a More Efficient Management (Torredembarra, Spain)

The aquifers of the Spanish Mediterranean coast are generally subjected to intense exploitationto meet the growing water supply demands. The result of the exploitation is salinizationdue to the marine saltwater intrusion, causing a deterioration in the quality of the water pumped,limiting its use for community needs, and not always being well delimited. To prevent deterioration,a groundwater control network usually allows precise knowledge of the areas affected by saltwaterintrusion but not the extent of the saline plumes. Moreover, the characterization of aquifer systemsrequires a model that defines the geometry of aquifer formations. For this objective, we integratedhydrogeological, hydrogeochemical, and electrical resistivity subsoil data to establish a hydrogeologicalmodel of the coastal aquifer of Torredembarra (Tarragona, NE Spain). In this research, wehave carried out a regional and local-scale study of the aquifer system to define the areas prone tobeing affected by saline intrusion (electrical resistivity values below 10 Wm). The obtained resultscould be used as a support tool for the assessment of the most favorable areas for groundwaterwithdrawal, as well as enabling the control and protection of the most susceptible areas to be affectedby saltwater intrusion.</p

Hydrogeophysical Assessment of the Critical Zone below a Golf Course Irrigated with Reclaimed Water Close to Volcanic Caldera

The geometry and the hydraulic properties of the unsaturated zone is often difficult to evaluate from traditional soil sampling techniques. Soil samples typically provide only data of the upper layers and boreholes are expensive and only provide spotted information. Non-destructive geophysical methods and among them, electrical resistivity tomography can be applied in complex geological environments such as volcanic areas, where lavas and unconsolidated pyroclastic deposits dominate. They have a wide variability of hydraulic properties due to textural characteristics and modification processes suh as compaction, fracturation and weathering. To characterize the subsurface geology below the golf course of Bandama (Gran Canaria) a detailed electrical resistivity tomography survey has been conducted. This technique allowed us to define the geometry of the geological formations because of their high electrical resistivity contrasts. Subsequently, undisturbed soil and pyroclastic deposits samples were taken in representative outcrops for quantifying the hydraulic conductivity in the laboratory where the parametric electrical resistivity was measured in the field. A statistical correlation between the two variables has been obtained and a 3D model transit time of water infiltration through the vadose zone has been built to assess the vulnerability of the aquifers located below the golf course irrigated with reclaimed water

Non-conventional water resources in coastal areas: a review of the use of reclaimed water

In an era of increasing concern for limited water resources a wise joint management of conventional and nonconventional water resources must be considered. Water scarcity aggravates in coastal zones which are often characterised by high population density, intense economic activity and tourism; meaning heavy seasonal water demands. The relationships between sea and land-water can also compromise the quality of available freshwater. In this context, the use of non-conventional water increases the availability of water supplies. Non-conventional water resources of low quality could be directed to meet several needs (like watering lawns, washing cars, flushing toilets and cooling systems, among others). Therefore, significantly more potable water would be available to meet human demand for safe water

Evaluation of reclamation technologies for wastewater reuse

Podeu consultar el llibre complet a: http://hdl.handle.net/2445/46988Reclamation and reuse of wastewater require the use of tools that minimize risks to health and natural ecosystems. There are various types of such tools, among which HACCP (hazard analysis and critical control points) and barrier systems are gaining importance. The research reported here aims to determine and evaluate the most efficient combinations of different treatment systems—barriers—for the reclamation of secondary effluents from urban sewage treatment plants, and for obtaining water of sufficient quality for reuse in accordance with existing legislation, in which water disinfection has become one of the keys to compliance. Several conventional and non-conventional reclamation technologies are evaluated. The results lead us to recommend treatment lines for the different reclaimed water uses established in the Spanish legislation

Non-conventional water resources in coastal areas: a review of the use of reclaimed water

In an era of increasing concern for limited water resources a wise joint management of conventional and nonconventional water resources must be considered. Water scarcity aggravates in coastal zones which are often characterised by high population density, intense economic activity and tourism; meaning heavy seasonal water demands. The relationships between sea and land-water can also compromise the quality of available freshwater. In this context, the use of non-conventional water increases the availability of water supplies. Non-conventional water resources of low quality could be directed to meet several needs (like watering lawns, washing cars, flushing toilets and cooling systems, among others). Therefore, significantly more potable water would be available to meet human demand for safe water

Bromine and bromide content in soils: Analytical approach from total reflection X-ray fluorescence spectrometry

Monitoring total bromine and bromide concentrations in soils is significant in many environmental studies. Thus fast analytical methodologies that entail simple sample preparation and low-cost analyses are desired. In the present work, the possibilities and drawbacks of low-power total reflection X-ray fluorescence spectrometry (TXRF) for the determination of total bromine and bromide contents in soils were evaluated. The direct analysis of a solid suspension using 20 mg of fine ground soil (<63 μm) gave a 3.7 mg kg−1 limit of detection for bromine which, in most cases, was suitable for monitoring total bromine content in soils (Br content range in soils = 5-40 mg kg−1). Information about bromide determination in soils is also possible by analyzing the Br content in water soil extracts. In this case, the TXRF analysis can be directly performed by depositing 10 μL of the internal standardized soil extract sample on a quartz glass reflector in a measuring time of 1500 s. The bromide limit of detection by this approach was 10 μg L−1. Good agreement was obtained between the TXRF results for the total bromine and bromide determinations in soils and those obtained by other popular analytical techniques, e.g. energy dispersive X-ray fluorescence spectrometry (total bromine) and ionic chromatography (bromide). As a study case, the TXRF method was applied to study bromine accumulation in two agricultural soils fumigated with a methyl bromide pesticide and irrigated with regenerated waste water