Sampling methods may drive short-term groundwater nitrate variability in an irrigated watershed connected to a coastal lagoon (Campo de Cartagena-Mar Menor, SE Spain).

This study highlights concerns regarding the reliability of groundwater nitrate data used in official surveys, such as within the EU-mandated Water Framework Directive (WFD). The focus is on the Campo de Cartagena - Mar Menor hydrosystem in Spain, a region known for its intensively irrigated watershed and eutrophicated lagoon, where monitoring the evolution of nitrate contamination in surface and groundwater is crucial but challenging due to the risk of inconsistent characterization leading to erratic remediation measures. The study employed an experimental approach in private wells that belong to a longstanding official nitrate survey network marked by irregular sampling practices. Importantly, these wells lacked comprehensive design documentation and were frequently used by farmers. The study aimed to evaluate the representativity of dissolved nitrate measurements in such an emblematic case, while investigating the source of the water using geochemical and isotope tracers. This assessment considered the effects of different sampling techniques (bailer or pumping) and sampling parameters (depth and time), acknowledging actual practices. The research highlights several key findings. Firstly, the bailer sampling method proved to account for a substantial portion of the observed variation in nitrate content. Secondly, in some cases, pumping introduced contributions from different water horizons, complicating the interpretation of nitrate data. Thirdly, alterations in the sampling protocol had a notable impact on the resulting nitrate measurements. Furthermore, the study emphasized a critical issue: the lack of analytical uncertainty estimation in official surveys introduces significant bias in result interpretation, with discrepancies exceeding 100 mg/L in four of the six wells analyzed. This underscores the pressing need for improved sampling protocols, dedicated borehole infrastructure and precise data interpretation. Given the potential unreliability of some official groundwater nitrate data shared under EU or other regulations, with corresponding economic and environmental impacts, the study recommends meticulous verification before transmitting data.

Water table prediction through causal reasoning modelling.

This research is mainly aimed to analyze and model the relationship of the binomial Rainfall-Piezometry. In this sense, the inherent causality contained in temporal hourly Rainfall and Groundwater levels (piezometry) data records has been taken. This has been done through Bayesian Causal Reasoning (BCR) which is technique belonging to Artificial Intelligence (AI) based on Bayesian Theorem. The methodology comprises two main stages, first an analytical method from classic regression analysis, and second, a Bayesian Causal Modelling Translation (BCMT) that itself comprises several iterative steps. This research ultimately becomes a tool for aquifers management that comprises a bivariate function made of two variables Rainfall and Piezometry (Temporal Groundwater level evolution). This innovative methodology has been successfully applied in the Quaternary aquifer of the Campo de Cartagena groundwater body, which is an aquifer system that directly is connected to Mar Menor coastal lagoon (Murcia region, SE Spain).

Integrating stakeholders' inputs to co-design climate resilience adaptation measures in Mediterranean areas with conflicts between wetland conservation and intensive agriculture.

Designing sustainable management strategies in groundwater-dependent socio-economic systems in areas with scarce water resources and protected wetlands is a challenging issue. The high vulnerability of these systems to droughts will be exacerbated even further under future climate change (CC) and socio-economic scenarios. A novel integrated bottom-up/top-down approach is used to identify "climate resilient pathways", from which to co-design adaptation strategies to reduce the impact of potential future CC and socio-economic scenarios. The approach followed two steps (1) the generation of local CC and socio-economic scenarios by downscaling global/regional climate models and (2) the identification and assessment of potential adaptation strategies through an iterative bottom-up/top-down approach. Top-down assessments of the impact of CC have been undertaken by propagating local scenarios within a chain of mathematical models based on expert criteria/assumptions. This allowed us to analyse of the physical vulnerability of the system under different potential CC and socio-economic scenarios by simulating them with a sequential modelling of rainfall-recharge, agriculture, and hydrological processes through a distributed groundwater finite difference model. These model results were discussed with the stakeholders at a first workshop, which aimed to identify potential adaptation strategies. The influence of the adaptation strategies on the future hydrological status was assessed by simulating them through the chain of models. These results were the inputs into the discussions at a second workshop, which aimed to validate and/or improve the results of the first workshop. The methodology was applied in the Upper Guadiana River Basin, where there is a long-standing conflict between wetland conservation and groundwater overexploitation for intensive agriculture. The future horizon 2016-2045 is analysed with the scenarios compatible with the emission scenario RCP4.5. The research has allowed us to conclude that groundwater pumping reduction would be the most robust and effective measure to reduce the impact of CC in the area.

Hydrogeological modelling for the watershed management of the Mar Menor coastal lagoon (Spain).

The Mar Menor is the largest lagoon along the Spanish Mediterranean coast. It suffers from eutrophication and algal blooms associated with intensive agricultural activities and urban pressure in the surrounding Campo de Cartagena plain. A balanced discharge of groundwater, carrier of algal nutrients such as nitrate, is essential to ensure the integrity of the coastal lagoon and the availability of groundwater resources inland. We here present a 3D hydrogeological model of the unconfined Quaternary aquifer that discharges into the lagoon. The model couples both surface water balance and groundwater dynamics and has been calibrated to available data in the period 2000-2016. The calibrated model allows understanding of the current state of the aquifer and its link to the lagoon. The potential discharge has been quantified in both space and time and falls between 69.5 and 84.9 hm3/yr during dry and wet periods, respectively (with values of nitrate discharge of 11.4-11.8 Mkg/yr in the absence of aquifer sink terms, e.g., leakage to deeper aquifers and pumping from groundwater wells). The predictive capabilities of the calibrated model can be used to test the impact of different integrated management scenarios on the surface-groundwater dynamics of the catchment. Three plausible management scenarios are proposed that include localized and distributed groundwater pumping (drains and groundwater wells, respectively). Results show the effectiveness of the scenarios in reducing the groundwater and nitrate discharge into the lagoon. The disadvantages of the proposed scenarios, including potential seawater intrusion, need to be balanced with their relative merits for the sustainable development of the region and the survival of the Mar Menor ecosystem. The modelling approach proposed provides a valuable tool for the integrated and holistic management of the Campo de Cartagena-Mar Menor catchment and should be of great interest to similar hydrological systems with high ecological value.

Groundwater intensive use and mining in south-eastern peninsular Spain: Hydrogeological, economic and social aspects.

Intensive groundwater development is a common circumstance in semiarid and arid areas. Often abstraction exceeds recharge, thus continuously depleting reserves. There is groundwater mining when the recovery of aquifer reserves needs more than 50years. The MASE project has been carried out to compile what is known about Spain and specifically about the south-eastern Iberian Peninsula and the Canary Islands. The objective was the synthetic analysis of available data on the hydrological, economic, managerial, social, and ethical aspects of groundwater mining. Since the mid-20th century, intensive use of groundwater in south-eastern Spain allowed extending and securing the areas with traditional surface water irrigation of cash crops and their extension to former dry lands, taking advantage of good soils and climate. This fostered a huge economic and social development. Intensive agriculture is a main activity, although tourism plays currently an increasing economic role in the coasts. Many aquifers are relatively high yielding small carbonate units where the total groundwater level drawdown may currently exceed 300m. Groundwater storage depletion is estimated about 15km(3). This volume is close to the total contribution of the Tagus-Segura water transfer, but without large investments paid for with public funds. Seawater desalination complements urban supply and part of cash crop cultivation. Reclaimed urban waste water is used for irrigation. Groundwater mining produces benefits but associated to sometimes serious economic, administrative, legal and environmental problems. The use of an exhaustible vital resource raises ethical concerns. It cannot continue under the current legal conditions. A progressive change of water use paradigm is the way out, but this is not in the mind of most water managers and politicians. The positive and negative results observed in south-eastern Spain may help to analyse other areas under similar hydrogeological conditions in a less advanced stage of water use evolution.

Hereditary apolipoprotein AI-associated renal amyloidosis: A diagnostic challenge.

Hereditary renal amyloidosis is an autosomal dominant condition with considerable overlap with other amyloidosis types. Differential diagnosis is complicated, but is relevant for prognosis and treatment. We describe a patient with nephrotic syndrome and progressive renal failure, who had a mother with renal amiloidosis. Renal biopsy revealed amyloid deposits in glomerular space, with absence of light chains and protein AA. We suspected amyloidosis with fibrinogen A alpha chain deposits, which is the most frequent cause of hereditary amyloidosis in Europe, with a glomerular preferential affectation. However, the genetic study showed a novel mutation in apolipoprotein AI. On reviewing the biopsy of the patient's mother similar glomerular deposits were found, but there were significant deposits in the renal medulla as well, which is typical in APO AI amyloidosis. The diagnosis was confirmed by immunohistochemistry. Apo AI amyloidosis is characterized by slowly progressive renal disease and end-stage renal disease occurs aproximately 3 to 15 years from initial diagnosis. Renal transplantation offers an acceptable graft survival and in these patients with hepatorenal involvement simultaneous liver and kidney transplantation could be considered.