Reactive and mixing processes governing ammonium and nitrate coexistence in a polluted coastal aquifer

A comprehensive hydrochemical, stable isotope and microbial analyses characterisation has been performed to evaluate the sources of groundwater, nitrogen pollution and degradation processes occurring in an industrial polluted coastal aquifer in the framework of a complex hydrodynamic system. The coexistence of ammonium and nitrate has been observed in almost all the investigated monitoring wells, reaching maximum values of 100 and 200 mg/L for both species. Chloride and potassium concentration coupled with groundwater stable isotopes data show the influence of local and urban recharge and the occurrence of seawater intrusion in areas near the coastline. δ15N–NH4+ values ranging between −4.9 and +14.9% suggest that different processes such as partial nitrification of ammonium, probably anammox activities and sorption, are occurring at the site. The isotope data for NH4+also showed the existence of the remnant of an old fertilizer plume in the downgradient area. The nitrate isotope data ranging between +9 and +46% and +6 and +26% for δ15N–NO3−and δ18O–NO3−, respectively, suggest that nitrate content is attenuated by denitrification and probably annamox. The fast groundwater flow field is one of the reasons for the coexistence of NH4+and NO3− in groundwater, since both compounds can penetrate the reducing zone of the aquifer. The influence of leakage of sewage pipelines on the aquifer cannot be discerned due to the complexities of the nitrogen attenuation processes, also influenced by pumping activities

Isotopic characterization of groundwater for drinking use in multilayer aquifers of the Milano and Monza provinces

Groundwater, drinking water, isotopes, EU directives, hydrogeolog

Groundwater flow and geochemical modeling of the Acque Albule thermal basin (Central Italy): a conceptual model for evaluating influences of human exploitation on flowpath and thermal resource availability

Although the Acque Albule Basin has been studied since the middle of the 19th century, a comprehensive geologic conceptual model of the area has not yet been developed. The natural setting has been heavily modified by anthropic activities. Rapid evolution during the last 25 years has caused many interferences, which have led to a drastic increase of the hazards and linked risks, mainly related to water resource overexploitation and subsidence. The implementation of an exhaustive framework has become mandatory for environmental and management purposes. Starting from a critical review of previous studies, hydrogeologic and hydrogeochemical surveys and related numerical modeling have been carried out in order to achieve a quantitative understanding of the active phenomena and processes. Several hydrogeologic issues have been addressed concerning aquifer recharge areas and the different flowpaths of groundwater in respect to their division into a shallow and a deep circuit. Account has been taken of the groundwater chemistry as a function of water—rock interactions and mixing processes with uprising fluids. Different scenarios of groundwater flow in the Acque Albule aquifer have been built, using previously available piezometric measurements and the hydrodynamic parameters determined by in situ tests. These results led to the formulation of an updated hydrogeologic conceptual model to be further implemented, in which past, present and future anthropic instances and the potential of natural resources of the area have been included and taken into account. A sound conceptual model must rely on the design and development of a logical geo-database in which information is stored, updated and processed. This operational framework can result in a useful tool for land management, surveys planning and design, hazard and risk evaluation, identification of best practices and economic development of the area

Multi-isotopic regional-scale screening on drinking groundwater in Lombardy Region (Italy)

Groundwater represents the main and safest source of water that supply, for drinking purposes, numerous urban and rural communities all over the world. A deep knowledge of aquifer systems in terms of quality, vulnerability and renewability is fundamental to preserve groundwater resources. Thanks to the contribution of different members of Water Alliance in synergy with Sapienza University, during November 2019 a multi-isotopic analysis at regional scale on groundwater tapped for drinking purposes in a wide area of Lombardy Region, has been carried out. The study aimed to improve knowledge about recharge mechanisms, groundwater relative age and impact of human activities on groundwater quality Each Water Alliance supplier selected wells and springs for a total of 121 samples, catching different aquifer groups and distributed from North to South. Groundwater stable isotope analyses were performed on all the monitoring points, instead tritium, nitrogen isotopes (15N and 18O in nitrates), sulphate isotopes (34S and18O) and 13C isotope in Dissolved Inorganic Carbon (DIC), were analysed in selected monitoring wells basing on previous data and major ions concentrations results. Therefore, results confirmed the key role of multi-isotopic approach in defining aquifer recharge processes, relative groundwater age and origin of pollutants, offering a useful tool to point out local issues which can be deeply investigated by each water supplier

Redox Dependent Arsenic Occurrence and Partitioning in an Industrial Coastal Aquifer: Evidence from High Spatial Resolution Characterization of Groundwater and Sediments

Superlative levels of arsenic (As) in groundwater and sediment often result from industrial pollution, as is the case for a coastal aquifer in Southern Italy, with a fertilizer plant atop. Understanding conditions under which As is mobilized from the sediments, the source of that As, is necessary for developing eective remediation plans. Here, we examine hydrogeological and geochemical factors that aect groundwater As concentrations in a contaminated coastal aquifer. Groundwater has been subject to pump-and-treat at a massive scale for more than 15 years and is still ongoing. Nevertheless, As concentrations (0.01 to 100 mg/L) that are four orders of magnitude more than Italian drinking water standard of 10 g/L are still present in groundwater collected from about 50 monitoring wells over three years (2011, 2016, and 2018). As was quantified in three dierent locations by sequential extractions of 29 sediment cores in 2018 (depth 2.5 m to 16.5 m b.g.l.), combined with groundwater As composition, the aqueous and solid partitioning of As were evaluated by partition coecient (Kd) in order to infer the evolution of the contaminant plumes. Most sediment As is found in easily extractable and/or adsorbed on amorphous iron oxides/hydroxides fractions based on sequential extractions. The study shows that As contamination persists, even after many years of active remediation due to the partitioning to sediment solids. This implies that the choice of remediation techniques requires an improved understanding of the biogeochemical As-cycling and high spatial resolution characterization of both aqueous and solid phases for sites of interes

Relationship between rainfall and water table in a coastal aquifer: the case study of Castelporziano presidential estate

This study is focused on the analysis of seasonal and annual variability in groundwater levels of the coastal aquifer of Castelporziano Presidential Estate, a protected area of 59 Km2 located in the periphery of Rome. A comparison with the local trends of rainfall at “Castello” gauging station at different time scales (monthly, seasonal and annual) has been carried out. The results highlight differences between the coastal area and eastern and northern sector of the Estate. Indeed, the seasonal effect due to local meteoric recharge is direct and regular during the year in the coastal area in respect to the eastern and northern sectors of the Estate. Moreover, annual steady regime and multi-year trend of groundwater levels suggest the contribution from the adjacent volcanic aquifer of Albani Hills. In the latter case, the regional circulation of groundwater is affected by the effects of intense withdrawals. The maintenance of the monitoring network will allow to define the flow paths of the groundwater that characterize the coastal aquifer of Castelporziano

L'efficacia personale percepita nel tutoring universitario: una scala di misura

Come attestato da molte ricerche, le convinzioni di autoefficacia consentono di raggiungere prestazioni scolastiche di successo e, in un percorso di tutoring, possono costituire un’informazione significativa per il miglioramento delle competenze accademiche. Obiettivo del contributo è presentare le proprietà psicometriche di una nuova scala di autoefficacia, composta da 47 affermazioni, specificamente creata per il contesto universitario, che è stata somministrata a un campione di 406 studenti universitari. I dati empirici forniscono una prima validazione dello strumento (vengono descritti la struttura fattoriale e gli indici di attendibilità emersi), incoraggiando al tempo stesso ulteriori ricerche in contesti universitari differenti. Vengono infine fornite indicazioni per l’impiego della scala all’interno di un percorso di sviluppo personale

VALIDATION OF A DENSITY DEPENDENT GROUNDWATER TRANSPORT MODEL USING MASS RECOVERY RATE

In this short note is described the validation process of a density dependent groundwater transport model, previously implemented and published, using the mass recovery rate of dissolved Total Petroleum Hydrocarbons and Chloride from 67 pumping wells in a polluted site. A good fit between observed and calculated values was recorded, supporting the feasibility of flow and transport models validation in complex polluted sites where pump & treat remediation are applied and management strategies need to be rapid and robust