Emma Petrella

Mixing of water in a carbonate aquifer, southern Italy, analysed through stable isotope investigations

O,δ 2 H). The input signal (rainwater) was compared with the isotopic content of a 35-meter groundwater vertical prof ile, over a 1-year period. Within the studied aquifer, recharge and flow are diffuse in a well-connected fissure network. At the test site, the comparison between input and groundwater isotopic signals illustrates that no efficient mixing takes place in the whole unsaturated zone, between the fresh infiltration water and the stored water. When analysing the stable isotope composition of groundwater, significant variations were observed above the threshold elevation of 1062 m asl, while a nearly constant composition was observed below the same threshold. Thus, temporal variations in stable isotope composition of rainwater are completely attenuated just in the deeper phreatic zone. On the whole, taking into consideration also the results of previous studies in the same area, the investigations showed that physical characteristics of the carbonate bedrock, as well as aquifer heterogeneity, are factors of utmost importance in influencing the complete mixing of water. These findings suggest a more complex scenario at catchment scale.

Updating of a DRASTIC-based Method for Specific Vulnerability Assessment in Carbonate Aquifers

Abstract Some methodological modifications are suggested to improve a DRASTIC-based method as a reliable predictor of microbial contamination in extensively fractured and subordinately karstified carbonate aquifers. These modifications will allow a better assessment of vulnerability induced by the concentrated infiltration of surface runoff in two different scenarios: (a) when the karst system is entirely located within an unsaturated aquifer and (b) when the karst system is partially located within a saturated medium. The effectiveness of the updated method has been experimentally verified by comparing the vulnerability values with the results of a hydrogeological and microbiological study at a test site.

Microorganisms as contaminants and natural tracers: a 10-year research in some carbonate aquifers (southern Italy)

Limestone aquifers provide the main drinking water resources of southern Italy. Due to cattle grazing and/or manure spreading, these aquifers are often characterized by microbial contamination of groundwater. The aim of this paper is to summarize the results obtained during a 10-year research carried out in experimental field sites in southern Italy, analyzing (1) the influence of the topsoil of pyroclastic origin on the migration of microbial cells from the ground towards the groundwater, and then on the groundwater vulnerability, (2) the influence of the rainfall regime on the breakthrough at the springs, (3) the reliability of thermotolerant coliforms and fecal enterococci as bacterial indicators of microbial contamination, and (4) the effectiveness of microorganisms as natural tracers for some hydrogeological purposes. The results obtained showed that fecal enterococci are a more reliable indicator than thermotolerant coliforms for detecting contamination and that the entity and distribution over time of microbial contamination of fecal origin are influenced by several factors, such as precipitation regime, thermal regime and existence and thickness of the topsoil of pyroclastic origin. Moreover, the migration of a significant amount of bacterial cells through the topsoil and the underlying carbonate rocks allows the utilization of microorganisms as effective natural tracers, to be coupled with other classic tracers to study the recharge and the flow processes. In a broader perspective, these results can be used to optimize the investigations in other hydrogeological scenarios, with emphasis on those where different water types coexist and interact in same aquifer systems.

A conceptual hydrogeological model of ophiolitic aquifers (serpentinised peridotite): The test example of Mt. Prinzera (Northern Italy)

&NA; The main aim of this study is the experimental analysis of the hydrogeological behaviour of the Mt. Prinzera ultramafic massif in the northern Apennines, Italy. The analysed multidisciplinary database has been acquired through (a) geologic and structural survey; (b) geomorphologic survey; (c) hydrogeological monitoring; (d) physico‐chemical analyses; and (e) isotopic analyses. The ultramafic medium is made of several lithological units, tectonically overlapped. Between them, a low‐permeability, discontinuous unit has been identified. This unit behaves as an aquitard and causes a perched groundwater to temporary flow within the upper medium, close to the surface. This perched groundwater flows out along several structurally controlled depressions, and then several high‐altitude temporary springs can be observed during recharge, together with several perennial basal (i.e., low altitude) springs, caused by the compartmentalisation of the system because of high‐angle tectonic discontinuities.

Bacterial migration through low-permeability fault zones in compartmentalised aquifer systems: a case study in Southern Italy

*emma.petrella@unimol.it Microbial contamination is frequently detected at different springs discharging within this type of aquifer system (Celico et al., 2004; Naclerio et al., 2008, 2009) and in carbonate environments in general (e.g., Personné et al., 1998; Pronk et al., 2006; Flynn & Sinreich, 2010). Nevertheless, no information is available concerning the role low-permeability fault zones play in the migration of microorganisms between adjacent compartments. Whether a fault zone will act as a conduit, barrier, or combined conduit-barrier system is controlled by the relative percentage of fault core and damage zone structures (e.g., in carbonates, Mollema & Antonellini, 1999; Salvini et al., 1999; Billi et al., 2003; Billi, 2005a; Agosta & Aydin, 2006; Billi et al., 2007; Balsamo et al., 2008; Storti & Balsamo, 2010). A fault zone can impede fluid flow when the fault core is well developed (e.g., Antonellini & Aydin, 1994; Newman & Mitra, 1994; Goddard & Evans, 1995; Caine et al., 1996; Bense et al., 2003; Fairley & Hinds, 2004). Fault cores can include single slip surfaces (Caine et al., 1991), highly indurated, INTRODUCTION

Use of molecular approaches in hydrogeological studies: the case of carbonate aquifers in southern Italy

Waterborne pathogens represent a significant health risk in both developed and developing countries with sensitive sub-populations including children, the elderly, neonates, and immune-compromised people, who are particularly susceptible to enteric infections. Annually, approximately 1.8 billion people utilize a faecally contaminated water source, and waterborne diseases are resulting in up to 2.1 million human mortalities globally. Although groundwater has traditionally been considered less susceptible to contamination by enteric pathogens than surface water due to natural attenuation by overlying strata, the degree of microbial removal attributable to soils and aquifers can vary significantly depending on several factors. Thus, accurate assessment of the variable presence and concentration of microbial contaminants, and the relative importance of potentially causative factors affecting contaminant ingress, is critical in order to develop effective source (well) and resource (aquifer) protection strategies. “Traditional” and molecular microbiological study designs, when coupled with hydrogeological, hydrochemical, isotopic, and geophysical methods, have proven useful for analysis of numerous aspects of subsurface microbial dynamics. Accordingly, this overview paper presents the principal microbial techniques currently being employed (1) to predict and identify sources of faecal contamination in groundwater, (2) to elucidate the dynamics of contaminant migration, and (3) to refine knowledge about the hydrogeological characteristics and behaviours of aquifer systems affected by microbial contamination with an emphasis on carbonate aquifers, which represent an important global water supply. Previous investigations carried out in carbonate aquifers in southern Italy are discussed.RésuméLes agents pathogènes d’origine hydrique représentent un risqué important pour la santé aussi bien dans les pays développés que dans les pays en développement avec des sous-populations sensibles notamment les enfants, les personnes âgées, les nouveaux nés, et les personnes immunodéprimées, qui sont particulièrement sensibles aux infections entériques. Chaque année, environ 1.8 milliard de personnes utilisent une source d’eau contaminée par des déchets fécaux, et les maladies transmises par l’eau entrainent jusqu’à 2.1 millions de décès de personnes dans le monde. Bien que les eaux souterraines aient traditionnellement été considérées comme moins sensibles à la contamination par les pathogènes entériques que les eaux de surface en raison de l’atténuation naturelle lors de l’infiltration au sein des couches géologiques supérieures, le degré d’élimination microbienne attribuable au sol et aux aquifères peut varier de manière significative selon plusieurs facteurs. Ainsi, une évaluation précise de la présence et de la concentration variable des contaminants microbiens, et de l’importance relative des potentiels facteurs de causalité qui influent sur la pénétration des contaminants, est essentielle pour développer des stratégies efficaces de protection des sources (puits) et des ressources (aquifères). Les méthodologies « traditionnelles » et de microbiologie moléculaire, associées aux méthodes hydrogéologiques, hydrochimiques, isotopiques, et géophysiques, se sont révélées utiles pour l’analyse de nombreux aspects de la dynamique microbienne souterraine. Par conséquent, cet article présente les principales techniques microbiennes actuellement utilisées (1) pour prédire et identifier les sources de contamination fécale dans les eaux souterraines, (2) pour élucider la dynamique de migration des contaminants, et (3) pour affiner les connaissances relatives aux caractéristiques hydrogéologiques et aux comportements des systèmes aquifères affecté par une contamination microbienne, en mettant l’accent sur les aquifères carbonatés, qui représentent une importante source d’approvisionnement en eau potable à l’échelle mondiale. Des recherches antérieures réalisées dans les aquifères carbonatés du Sud de l’Italie sont discutées.ResumenLos patógenos transmitidos por el agua representan un riesgo significativo para la salud en países desarrollados y en desarrollo con subpoblaciones sensibles que incluyen niños, ancianos, neonatos y personas inmunocomprometidas, que son particularmente susceptibles a las infecciones entéricas. Anualmente, aproximadamente 1.8 billones de personas utilizan una fuente de agua contaminada por contaminantes fecales, y las enfermedades transmitidas por el agua están causando hasta 2.1 millones de muertes humanas en todo el mundo. Aunque el agua subterránea ha sido tradicionalmente considerada menos susceptible que el agua superficial a la contaminación por patógenos entéricos debido a la atenuación natural por los estratos suprayacentes, el grado de eliminación microbiana atribuible a los suelos y acuíferos puede variar significativamente dependiendo de varios factores. Por lo tanto, una evaluación precisa de la presencia y la concentración variable de contaminantes microbianos, y la importancia relativa de factores potencialmente causales que influyen en la entrada de contaminantes, es crítica para desarrollar estrategias efectivas de protección de fuentes (pozos) y recursos (acuíferos). Los diseños de estudios microbiológicos “tradicionales” y moleculares, junto con métodos hidrogeológicos, hidroquímicos, isotópicos y geofísicos, han demostrado ser útiles para el análisis de numerosos aspectos de la dinámica microbiana subterránea. En este trabajo se presentan las principales técnicas microbianas utilizadas actualmente (1) para predecir e identificar fuentes de contaminación fecal en agua subterránea, (2) para dilucidar la dinámica de la migración de contaminantes, y (3) para refinar el conocimiento sobre las características y comportamientos hidrogeológicos de los sistema acuíferos afectados por la contaminación microbiana con un énfasis en los acuíferos carbonáticos, que representan un importante suministro de agua a nivel mundial. Se discuten investigaciones previas realizadas en acuíferos carbonáticos en el sur de Italia.摘要水生病原体在发达国家和发展中国家对特别容易受到肠道感染的敏感亚群体包括儿童、老人、新生儿以及缺乏免疫的人群具有很大的健康风险。每年大约18亿人在使用粪便污染的水源,每年水传播疾病导致全球210万人死亡。尽管传统上认为,由于上伏地层的自然稀释,地下水与地表水相比不容易受到污染,但土壤和含水层中的微生物消除程度变化非常大,取决于好几个因素。因此,精确评价微生物污染物存在的变化情况及其含量、以及影响污染物进入的潜在因素的相对重要性至关重要,为的就是提出有效的水源(井)和资源(含水层)保护策略。“传统的”和分子微生物研究设计与水文地质、水化学、同位素以及地球物理方法结合一起时,就能证明对于分析地表之下微生物动力学的众多方面非常有用。因此,本篇综述性文章展示了目前采用的主要微生物技术:(1)预测和确认地下水中的粪便污染源;(2)阐明污染物运移的动力学;(3)提炼受到微生物污染的含水层系统水文地质特征和习性方面的知识,重点放在代表全球重要供水水源的碳酸盐岩含水层上。还论述了先前在意大利南部对碳酸盐岩含水层进行的调查。ResumoPatógenos transmitidos pela água representam um risco à saúde significante tanto em países desenvolvidos quanto em desenvolvimento com subpopulações sensíveis incluindo crianças, idosos, neonatos, e pessoas com imunidade comprometida, que são particularmente susceptíveis a infecções entéricas. Anualmente, aproximadamente 1.8 bilhão de pessoas utilizam fontes de água contaminadas por organismos fecais, e doenças de vinculação hídrica tem resultado em mais de 2.1 milhões de mortes globalmente. Apesar das águas subterrâneas terem sido consideradas tradicionalmente menos susceptíveis à contaminação por patógenos entéricos que as águas superficiais devido à atenuação natural dos estratos de cobertura, o grau de remoção microbiana atribuível ao solo e aos aquíferos pode variar significativamente dependendo de diversos fatores. Consequentemente, a avaliação precisa da presença variável e da concentração de contaminantes microbianos, e a importância relativa de fatores potencialmente causais que afetam a entrada de contaminantes, é crítica para desenvolver estratégias eficazes de proteção de fontes (poço) e recursos (aquíferos). Os projetos de estudos microbiológicos “tradicionais” e moleculares, quando combinados com métodos hidrogeológicos, hidroquímicos, isotópicos e geofísicos, têm se mostrado úteis para a análise de vários aspectos da dinâmica microbiana subterrânea. Assim, este artigo de síntese apresenta as principais técnicas microbianas atualmente utilizadas (1) para prever e identificar fontes de contaminação fecal em águas subterrâneas, (2) para elucidar a dinâmica de migração de contaminantes, e (3) para aperfeiçoar o conhecimento sobre as características e comportamentos hidrogeológicos de sistemas aquíferos afetados pela contaminação microbiana, com ênfase nos aquíferos carbonáticos, que representam um importante suprimento de água global. Investigações anteriores realizadas em aquíferos de carbonatos no sul da Itália são discutidas.

Potential role of Bacillus endospores in soil amended by olive mill wastewater

The main aim of this work was to know how spread is laccase activity in spores of Bacillus species isolated from a soil where Italian law allows olive mill wastewater (OMW) spreading, and to investigate the potential role of such autochthonous soil microorganisms in degradation of OMW phenols, and prevention of groundwater pollution. Laccase activity was detected for the first time in spores of wild-type Bacillus pumilus, B. cereus sensu lato, and B. amyloliquefaciens strains. Because B. pumilus, B. cereus sensu lato, and B. amyloliquefaciens, together with B. subtilis account for a total of 93% of Bacillus isolates at the study site, the nearly totality of Bacillus spores reveals laccase activity. Thus, taking also into consideration that Bacillus spores are more abundant (about 100-fold) than white-rot fungi (that possess a well known extracellular, radical-based ligninolytic enzyme system capable of degrading OMW phenols) in the studied soil, these spores may contribute to in-situ degradation of OMW phenols. This role is further emphasized by dilution of crude OMW during infiltration of rainwater through soil that allows to minimize the antibacterial activity of phenols. The widespread presence of Bacillus spores in soils indicates a potential detoxifying role of these spores in a broader context.

Integrative measures for protection of carbonate aquifers against microbial pollution in central–southern Italy

The refinement of groundwater protection criteria is currently of major importance in Italy. The present study has been focused on the refinement of protection measures for carbonate aquifers in central–southern Italy, taking into consideration their hydrogeological features and the results of several years of experimental research in different test sites. In these aquifers a good protection can be obtained by integrating the Italian law with specific solutions. The “map of land use restrictions” has been identified as the graphic core of a GIS-based sDSS which will aid decision-makers to protect the water resources against pollution.

A Python Script to Compute Isochrones for MODFLOW

MODFLOW constitutes today the most popular modeling tool in the study of water flow in aquifers and in modeling aquifers. To simplify the interface to MODFLOW various GUI have been developed for the creation of model definition files and for the visualization and interpretation of results. Recently Bakker et al. (2016) developed the FloPy interface to MODFLOW that allows to import and use the produced simulation data using Python. This allows to construct model input files, run the models, read and plot simulations results through Python scripts. In this note, we present a Python program (that uses FloPy) interface that allows us to generate time-related capture zones (isochrones) for confined 2D steady-state groundwater flow in unbounded domains, with one or more wells. As an application, we show a validation of the approach and the results of four basic test cases: a homogenous aquifer with one well, a heterogeneous aquifer with one well, an aquifer with four wells located both longitudinal and perpendicular to the flow direction.

A multidisciplinary procedure to evaluate and optimize the efficacy of hydraulic barriers in contaminated sites: a case study in Northern Italy

In the last decades, hydraulic barriers have been activated in a large number of polluted sites with the aim of preventing groundwater pollution outside the contaminated area. From a regulatory point of view, there is the need of evaluating the efficacy of these barriers. For this reason, the goal of the present study is to apply a coupled experimental modelling approach aimed at evaluating the efficacy of the barrier and providing management strategies. In particular, a case study in Italy is investigated. The study case is of main interest because of its complexity due to a heterogeneous aquifer and the presence of surface water that interacts with the below aquifer. The study has been carried out through the experimental characterization of the aquifer system (coupling the classic stratigraphic techniques with the results of radiocarbon dating, as well as through pumping and injection tests) and its hydrogeological behaviour (by means of hydraulic- and the stream-head measurements, as well as some isotopic investigations), and the implementation of a numerical model (through MODFLOW 2005). The results show the effectiveness of the coupled experimental modelling approach to analyse and simulate the hydrodynamics within the test aquifer system, as well as to evaluate the efficacy of the hydraulic barrier. Based on the results of the numerical model, easy solutions were designed to manage the barrier.