Sergio Rusi

Human alteration of groundwater–surface water interactions (Sagittario River, Central Italy): implication for flow regime, contaminant fate and invertebrate response

Many rivers worldwide are undergoing severe man-induced alterations which are reflected also in changes of the degree of connectivity between surface waters and groundwater. Pollution, irrigation withdrawal, alteration of freshwater flows, road construction, surface water diversion, soil erosion in agriculture, deforestation and dam building have led to some irreversible species losses and severe changes in community composition of freshwater ecosystems. Taking into account the impact of damming and flow diversion on natural river discharge, the present study is aimed at (i) evaluating the effects of anthropogenic changes on groundwater/surface water interactions; (ii) analyzing the fate of nitrogenous pollutants at the floodplain scale; and (iii) describing the overall response of invertebrate assemblages to such changes. Hydrogeological, geochemical and isotopic data revealed short- and long-term changes in hydrology, allowing the assessment of the hydrogeological setting and the evaluation of potential contamination by nitrogen compounds. Water isotopes allowed distinguishing a shallow aquifer locally fed by zenithal recharge and river losses, and a deeper aquifer/aquitard system fed by surrounding carbonate aquifers. This system was found to retain ammonium and, through the shallow aquifer, release it in surface running waters via the hyporheic zone of the riverbed. All these factors influence river ecosystem health. As many environmental drivers entered in action offering a multiple-component artificial environment, a clear relationship between river flow alteration and benthic and hyporheic invertebrate diversity was not found, being species response driven by the combination of three main stressors: ammonium pollution, man-induced changes in river morphology and altered discharge regime.

Boron-rich groundwater in Central Eastern Italy: a hydrogeochemical and statistical approach to define origin and distribution

Analysis of boron within groundwater was undertaken for an area of Central Eastern Italy. Although boron is a minor analyte in groundwater, concentrations can often be above limits set by legislation. A hydrogeochemical study, supported by a statistical multifactorial analysis, was undertaken to investigate the most likely origin of the boron within the groundwater. It was possible to distinguish contamination caused by anthropogenic activities from natural pollution within the study. Hydrochemical analysis has highlighted that anomalous concentrations of boron are only seen in groundwater from the alluvial valley deposits. A strong correlation between high boron concentrations and groundwater with chloride-sodium facies was also identified. The principal components analysis has confirmed the results from the assessment undertaken with hydrochemical analysis. The most important component is characterised by high loading of boron, sodium, chloride and electrical conductivity. The most likely origin of the boron within the hydrogeochemical context of the area appears to be connected to the uprise of chloride-sodium connate groundwaters naturally enriched in boron.

Hydrogeological mapping of the highly anthropogenically influenced Peligna Valley intramontane basin (Central Italy)

This paper presents hydrogeological mapping of the Peligna Valley (Central Italy) intramontane basin. The basin is hydrogeologically complex due to the significant surface and underground water resources which are extensively used for potable, industrial, agricultural and healing purposes. The basin history is characterised by significant fluvio-lacustrine deposition whose thickness can reach as much as 500 m. The depositional environment is completely surrounded by calcareous mountains. These represent extensive aquifers which feed large regional point and linear springs with total discharges of 16 m3/s. The highly complex hydrogeology of the study area and the varied use of water resources required extensive data collation and geological and hydrogeological assessments. Two years worth of hydrodynamic and hydrochemical monitoring of wells, springs, rivers and particularly artificial channels that convey water for industrial, hydroelectric and irrigational purposes were also undertaken. The construction of an accurate spatial-temporal database allowed the assessment and mapping of complex relationships between superficial water and groundwater. These relationships are shown in the 1:25,000 scale map. The map has been compiled using a detailed descriptive legend, various hydrogeological sections, schematics of anthropogenic activities, diagrams and tables and, finally, four schematics at 1:150,000 scale showing risk of contamination. It is hoped that this layout will assist in reading the map independently from any other supporting material.

Shallow Electrical and Seismic Imaging of The Pineto Mud Volcano (Central Italy)

Shallow underground electrical and seismic imaging was undertaken at the Pineto (Central Italy) Mud Volcano site using 2D-3D electrical resistivity tomography (ERT) and 2D reflection seismic surveys. This mud volcano or mud lump (known by the local population as “Cenerone Mud Volcano”) appears as a dome of about 15x10 m in size. The height is approximately 2 m with a crater 2.5 m of diameter where emission of fluids and solids (cold brine, mud, gas) occurs. Upper Pliocene-Lower Pleistocene foredeep pelitic deposits (clays with silty-sandy levels) overlain by clayey-silty deposits outcrop in the area. Below the Middle Pliocene deposits, a NNW-SSE anticline which runs approximately 2 kilometers to the WSW of the site represents the main element of the compressional tecnonic setting. Ditchs and streams in the area run along fault systems that are oriented NW-SE and NE-SW. These could be related to the upward migration of deep mud fluids. 2D-ERT results were used to determine the geometry of the high conductivity body related to the uprising of mud fluids and detecting changes in deposits. Detailed geometry reconstruction of the shallow upward migration of mud fluids was obtained by using 3D-ERT. A shear wave reflection seismic survey was undertaken to determine stratigraphic limits and to assess the occurrence of fractured zones along which mud fluids could migrate towards the surface. The survey results revealed that the uprising of deep fluids doesn’t occur exactly below the mud volcano at present. Instead, a high conductivity body occurs at approximately 60 m to the ENE, within a fractured zone in the undercompacted clays. The probable occurrence of a high permeability layer approximately between 20 m and 30 m below ground level, confined by clay layers, gives rise to an overpressured mud reservoir. This is the source of mud fluids which flow to the surface through a mud conduit that appears nearly horizontal at depth and then inclined towards the surface up to the mud volcano crater.

Ring maps applied to hydrogeological and environmental studies in alluvial aquifers, central Italy

Analysis of hydrogeological data of aquifers requires assessment of multiple variables and this is difficult to visualise in a single map with commonly used techniques. Ring maps are presented in this paper as a useful option to overcome this limitation. Four alluvial aquifers from Central Italy were assessed and are presented as case studies, evaluating the hydrogeological setting, the groundwater chemistry and the distribution of representative contaminants (Boron, Iron, Manganese and Nitrates). The final result is a graphical representation showing the ring maps, which simultaneously depict 12 numerical variables and two other variables: the geographical position and the main lithological properties of the aquifers. The research indicates that coastal alluvial aquifers show higher contamination when compared to the intramontane alluvial aquifers. Boron is exclusively present in the coastal alluvial aquifers where maximum concentrations are associated with the uprising of deeper saline groundwater with a chloride-sodium chemistry. Iron and manganese are generally associated and their presence is inversely correlated to that of nitrates. The presence of Nitrates is less common in the intramontane aquifers. The ring maps presented in this paper have been effectively used as a geovisualisation tool for multivariate hydrogeological and environmental data. The technique simultaneously and clearly shows several variables in one single graphical representation.

Detection of the natural origin hydrocarbon contamination in carbonate aquifers (central Apennine, Italy)

The water–rock interaction is discussed in this study for some Central Apennine aquifers and their relative springs, where the geological and hydrogeological setting is potentially responsible for hydrocarbon contamination. The contamination is related to the presence of limestone formations with high organic content that are connected to the genesis of hydrocarbons in the Central-Southern Apennines. Thanks to a multidisciplinary approach based on a seasonal monitoring of hydrogeological, hydrogeochemical, organic chemical, and isotopic variables, and to a detailed geological analysis, it was possible to demonstrate that the bituminous schists within the bituminous dolomite formation (a Triassic Formation presents in the Gran Sasso acquifer), the bituminous intercalations within the Bolognano Formation (an Olocenic calcareous Formation in the Majella acquifer), and the petroleum-saturated rocks of the Bolognano Formation (in the Morrone acquifer) are all able to leach hydrocarbons into groundwater. The results suggest that more detailed studies are required for areas where lithologies with fossil organic components are present. Insights should further investigate the interaction between groundwater and rocks in terms of organic compounds as well as inorganic compounds. In particular, the study also suggests that the supplementary quantification of hydrocarbon compounds in bituminous rock and the leaching tests are analyses that provide reliable results. From the normative point of view, the results of the study can be useful when dealing with hydrocarbon contamination resulting from anthropogenic activities within catchments where formations with high concentration of organic matter are present. In these cases, it will possible to assess the natural background concentrations and review the threshold values upwards.

Evaluation of processes controlling Fe and Mn contamination in the San Pedro Sula porous aquifer (North Western Honduras)

A multidisciplinary approach has been used, integrating statistical multivariate analysis and hydrogeochemical modeling, in order to evaluate processes that cause high concentration of iron and manganese in drinking water wells exploiting the San Pedro Sula porous aquifer.The analyses carried out have allowed to individuate a close relationship between the heavy eutrophication conditions of surface water, due to uncorrect management of waste water and to land use impact, and redox processes diffusion in groundwater, that cause Fe and Mn mobilisation.

From Korea to Catania: a busy September for IAH Italy

Si è appena concluso Il 45° Congresso internazionale IAH del 2018, che si è tenuto a Daejeon, in Korea, dal 9 al 14 settembre. Il Congresso era articolato in nove main topics sul tema: “Groundwater and Life: Science & Technology into Action”, e nel dettaglio: • T1 Groundwater and Life: Progress towards the Solution of Critical Problems; • T2 Spotlight on Modeling, Emerging Technologies and Their Applications; • T3 Global/Regional Environmental Changes and Their Consequences; • T4 Strategies to Assure the Sustainability of Groundwater Resources; • T5 Groundwater Quality and Contamination; • T6 Groundwater and Surface Water: an Integrated View; • T7 Advances in Karst and Fractured-rock Hydrogeology; • T8 Coastal Zone Management and Water Resources; • T9 Groundwater and Energy. I partecipanti sono stati numerosi (702), provenienti da 63 diverse nazioni e prevalentemente dalla Korea (469) e dal resto dell’Asia, ma con una discreta rappresentanza europea, con l’Italia seconda subito dietro alla Germania come numero di partecipanti (16). Gli abstract presentati sono stati 550 di cui 13 italiani (sesto paese insieme al Canada e davanti agli Stati Uniti). Il congresso IAH ha offerto molti motivi di richiamo: tra le 10 keynote lectures, tutte con un ottimo successo di pubblico, di rilievo quelle di Frank Schwartz e Makoto Taniguchi, ma anche le altre hanno offerto spunti interessanti, rivelando in taluni casi contesti idrogeologici molto diversi dai nostri, ma la cui gestione può essere un modello a scala globale. L’organizzazione delle sessioni orali nelle varie sale del DCC (Daejeon Convention Center) è stata impeccabile, avvalendosi anche dell’alta tecnologia coreana, e le sessioni poster ben organizzate. Il terzo giorno del Congresso è stato dedicato ai field trips, che avevano come oggetto l’illustrazione di casi di studio stimolanti dal punto di vista scientifico e naturalistico (es. il karst e i parchi geologici) nonché tecnico (es. visite a impianti geotermici, idroelettrici e nucleari, a dighe, e discariche). Il gruppo degli idrogeologi italiani è stato accolto prima del convegno a Seoul con una cena in un ristorante tipico coreano (Fig. 1) dall’addetto scientifico dell’Ambasciata d’ Italia, prof. Francesco Canganella, che aveva in precedenza stabilito un contatto con il Kigam (Korea Institute of Geoscience and Mineral Resources), grazie al quale IAH Italia ha potuto interagire e organizzare congiuntamente la sessione bilaterale Korea Italia sul “Monitoring and management of coastal aquifers”. Questa sessione (Fig. 2), convenors Marco Masetti e Heesung Yoon, responsabile per l’idrogeologia del Kigam, visto il cospicuo numero di interventi (11, di cui 5 coreani e 6 italiani) è stata suddivisa in due sotto-sessioni e ha avuto un grande successo, Fig.1: The Italian delegation and the scientific officer of the Italian Embassy, prof. Francesco Canganella, at the dinner in the typical Korean restaurant in Seoul.

Contribution of B and Sr Isotopes to assess boron contamination of groundwater: case studies in Central Italy

The present work aims to assess the origin of the boron contamination of groundwater that affect some areas of central-Adriatic Italy, through the use of boron and strontium isotopic analysis. The research results indicate that boron contamination is mainly related with salinization of groundwater attributable to the uprising of connate groundwater and mixing processes between more shallow fresh groundwater and deeper saline groundwater. As a result, the main boron contamination of groundwater is not related to anthropogenic inputs but rather to natural processes.