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

Hydrogeochemical changes before and during the 2016 Amatrice-Norcia seismic sequence (central Italy)

Seismic precursors are an as yet unattained frontier in earthquake studies. With the aim of making a step towards this frontier, we present a hydrogeochemical dataset associated with the 2016 Amatrice- Norcia seismic sequence (central Apennines, Italy), developed from August 24th, with an Mw 6.0 event, and culminating on October 30th, with an Mw 6.5 mainshock. The seismic sequence occurred during a seasonal depletion of hydrostructures, and the four strongest earthquakes (Mw ≥ 5.5) generated an abrupt uplift of the water level, recorded up to 100 km away from the mainshock area. Monitoring a set of selected springs in the central Apennines, a few hydrogeochemical anomalies were observed months before the onset of the seismic swarm, including a variation of pH values and an increase of As, V, and Fe concentrations. Cr concentrations increased immediately after the onset of the seismic sequence. On November 2016, these elements recovered to their usual low concentrations. We interpret these geochemical anomalies as reliable seismic precursors for a dilational tectonic setting

the geology and hydrogeology of the cassino plain central apennines italy redefining the regional groundwater balance

Cassino plain is a Quaternary intermontane basin of the central-southern Apennines, Italy. The plain has outstanding groundwater resources (total discharge of 23,000 L/s), thanks to the huge karst basins that surround the area. The area has been involved in many hydrogeological interests since the 1970s due to the economic importance and construction of the Western Campania Aqueduct for the water supply of Naples city and its hinterland. Despite its importance, the area lacks a common accepted hydrogeological conceptual model due to the complex geological setting. Two contrasting conceptual models already exist in the literature, with the first model based on a quantitative hydrogeological approach and the second on fieldwork. Through a literature analysis and further detailed field surveys, a new conceptual model is presented, acknowledging the thrust tectonics of the Apennine chain. The model unveils the most important hydrogeological issues of the area, serving as a useful tool for groundwater management, as well as for considering the changing anthropic and climate scenarios. In particular, the study redefines the hydrostructure extents and the groundwater flowpaths, characterizing the main water resources as Gari and Peccia springs

Monitoring of composition of LNAPL: essential tool for the estimation of free LNAPL specific volumes

Light Non-Aqueous Phase Liquid, Pancake Model, Vertical Equilibrium Mode

Exploring copepod distribution patterns at three nested spatial scales in a spring system. Habitat partitioning and potential for hydrological bioindication

In groundwater-fed springs, habitat characteristics are primarily determined by a complex combination of geomorphic features and physico-chemical parameters, while species assemblages are even more intricate. Springs host species either inhabiting the spring mouth, or colonizing spring habitats from the surface or from the aquifers which feed the springs. Groundwater species living in springs have been claimed as good candidates for identifying dual aquifer flowpaths or changes in groundwater pathways before reaching the spring outlets. However, the reliability of spring species as hydrological biotracers has not been widely investigated so far. Our study was aimed at analysing a large karstic spring system at three nested spatial scales in order: i) to assess, at whole spring system scale, the presence of a groundwater divide separating two aquifers feeding two spring units within a single spring system, by combining isotope analyses, physico-chemistry, and copepod distribution patterns; ii) to test, at vertical spring system scale, the effectiveness of copepods in discriminating surface and subsurface habitat patches within the complex mosaic spring environment; iii) to explore, at local spring unit level, the relative role of hydrochemistry and sediment texture as describers of copepod distribution among microhabitats. The results obtained demonstrated the presence of a hierarchical spatial structure, interestingly reflected in significant differences in assemblage compositions. Copepod assemblages differed between the two contiguous spring units, which were clearly characterized by their hydrochemistry and by significant differences in the groundwater flowpaths and recharge areas, as derived by the isotope analyses. The biological results suggested that stygobiotic species seem to be related to the origin of groundwater, suggesting their potential role as hydrological biotracers. At vertical scale, assemblage composition in surface and subsurface habitats was significantly different, both between spring units and among microhabitats, supporting strong habitat preferences of copepod species. At the smaller local scale, the response to habitat patchiness of subsurface copepod assemblages resulted in distribution patterns primarily defined by sediment texture, while the sensitivity to differences in hydrochemistry was negligible

A Multi-Hazard Extreme Climate Index across Europe

The ECI is a multi-hazard index which has been developed in the context of the eXtreme Climate Facilities (XCF) project lead by ARC (African Risk Capacity) with the objective of detecting the occurrence of climate extremes over the African continent. The main hazards covered by ECI are the extreme dry, wet and heat events. However, the definition of ECI allows for the integration of additional hazards in the same index. The index has been designed and widely tested across Africa. The objective of this study is to test the usability and potential application of the same index under different climate regimes that are typical of the mid-latitudes, including the Mediterranean area and northern Europe. The analysis presented in this study shows that the ECI allows an accurate detection of extreme cold/heat waves as well as events of abundant precipitation across Europe over the last decade

Diurnal and semidiurnal cyclicity of Radon (222Rn) in groundwater, Giardino Spring, Central Apennines, Italy

Understanding natural variations of Rn (222Rn) concentrations is the fundamental prerequisite of using this radioactive gas as a tracer, or even precursor, of natural processes, including earthquakes. In this work, Rn concentrations in groundwater were continuously measured over a seven-month period, during 2017, in the Giardino Spring, Italy, together with groundwater levels in a nearby well installed into a fractured regional aquifer. Data were processed to reduce noise, and then analyzed to produce the Fourier spectra of Rn concentrations and groundwater levels. These spectra were compared with the spectrum of tidal forces. Results showed that diurnal and semidiurnal cycles of Rn concentrations, and filtered oscillations of groundwater levels, in the nearby well, are correlated with solar and luni-solar components of tidal forces, and suggested no correlation with the principal lunar components. Therefore, influencing factors linked to solar cycles, such as daily oscillations of temperature and atmospheric pressure, and related rock deformations, may have played a role in Rn concentrations and groundwater levels. An open question remains regarding the correlation, which is documented elsewhere, of Rn concentrations and groundwater levels with the lunar components of the solid Earth tides

A Firenze messe le basi per una Piattaforma internazionale per una corretta gestione delle risorse idriche sotterranee

II 10 dicembre, in occasione della Giornata dei Diritti umani si è tenuto a Firenze, nella monumentale Sala dei Cinquecento di Palazzo Vecchio, il 1° Workshop su: "Uso delle risorse idriche sotterranee in periodi siccitosi. Esperienze dalla Toscana al resto del mondo", organizzato dalla Sezione Italiana dell'Associazione Internazionale degli Idrogeologi (IAH) con Aquifera onlus e patrocinato, oltre che dalla Regione Toscana e dal Comune di Firenze (che ha gentilmente concesso l'uso della sala), dalla Società Geologica Italiana (SGI), dal Consiglio Nazionale dei Geologi (CNG) e dal'IAH-Burdon Groundwater Network for International Development [...]

The synthesis of decades of groundwater knowledge: the new Hydrogeological Map of Rome

This paper describes the contents and the path taken to get to the new Hydrogeological map of the City of Rome. The map, which is the result of a combination of "expert elaborations" and GIS processing performed using the most recent available data, extends to the entire municipality (1285 km2) and is based on both the most recent scientific studies on groundwater field and new survey activities carried out in order to fill the data gaps in several areas of the examined territory. The work represents also an example of inter-institutional collaboration between government agencies, research institutes and universities

Hydrochemical determination of source water contributions to Lake Lungo and Lake Ripasottile (central Italy)

Lake Lungo and Lake Ripasottile are two shallow (4-5 m) lakes located in the Rieti Basin, central Italy, that have been described previously as surface outcroppings of the groundwater table. In this work, the two lakes as well as springs and rivers that represent their potential source waters are characterized physio-chemically and isotopically, using a combination of environmental tracers. Temperature and pH were measured and water samples were analyzed for alkalinity, major ion concentration, and stable isotope (δ2H, δ18O, δ13C of dissolved inorganic carbon, and δ34S and δ18O of sulfate) composition. Chemical data were also investigated in terms of local meteorological data (air temperature, precipitation) to determine the sensitivity of lake parameters to changes in the surrounding environment. Groundwater represented by samples taken from Santa Susanna Spring was shown to be distinct with SO4 2- and Mg2+ content of 270 and 29 mg/L, respectively, and heavy sulfate isotopic composition (δ34S=15.2‰ and δ18O=10‰). Outflow from the Santa Susanna Spring enters Lake Ripasottile via a canal and both spring and lake water exhibits the same chemical distinctions and comparatively low seasonal variability. Major ion concentrations in Lake Lungo are similar to the Vicenna Riara Spring and are interpreted to represent the groundwater locally recharged within the plain. The δ13CDIC exhibit the same groupings as the other chemical parameters, providing supporting evidence of the source relationships. Lake Lungo exhibited exceptional ranges of δ13CDIC (±5‰) and δ2H, δ18O (±5 ‰ and ±7 ‰, respectively), attributed to sensitivity to seasonal changes. The hydrochemistry results, particularly major ion data, highlight how the two lakes, though geographically and morphologically similar, represent distinct hydrochemical facies. These data also show a different response in each lake to temperature and precipitation patterns in the basin that may be attributed to lake water retention time. The sensitivity of each lake to meteorological patterns can be used to understand the potential effects from long-term climate variability