Monitoraggio idrogeochimico e modellazione numerica dei processi di salinizzazione dell'acquifero costiero ferrarese

Because of the potentially irreversible impact of groundwater quality deterioration in the Ferrara coastal aquifer, answers concerning the assessment of the extent of the salinization problem, the understanding of the mechanisms governing salinization processes, and the sustainability of the current water resources management are urgent. In this light, the present thesis aims to achieve the following objectives: Characterization of the lowland coastal aquifer of Ferrara: hydrology, hydrochemistry and evolution of the system The importance of data acquisition techniques in saltwater intrusion monitoring Predicting salinization trends in the lowland coastal aquifer Ammonium occurrence in a salinized lowland coastal aquifer Trace elements mobility in a saline coastal aquiferA causa dell'impatto potenzialmente irreversibile del deterioramento della qualità delle risorse idriche , l'obiettivo primario di questa tesi è stato quello di ottenere una comprensione quantitativa dei processi che hanno causato la salinizzazione delle acque sotterranee nella falda acquifera costiera ferrarese. In secondo luogo si è voluto indagare l’impatto che i cambiamenti climatici potranno avere sul processo di salinizzazione in atto e le eventuali conseguenze che un aumento di salinità possono avere sulla mobilizzazione di contaminanti sia maggiori che in tracce. Alla luce di quanto detto sin qui, lo studio in oggetto si propone di raggiungere i seguenti obiettivi: - Caratterizzazione della falda acquifera costiera della pianura di Ferrara: idrologia, idrochimica ed evoluzione del sistema - Importanza di tecniche di monitoraggio nella comprensione dei processi di salinizzazione - L’influenza della salinizzazione sui trend di concentrazione dell’ammonio e degli elementi nell’acquifero costiero - Previsione dei trend di salinizzazione della falda acquifera costier

High-resolution global grids of revised Priestley–Taylor and Hargreaves–Samani coefficients for assessing ASCE-standardized reference crop evapotranspiration and solar radiation

Abstract. The objective of the study is to provide global grids (0.5°) of revised annual coefficients for the Priestley–Taylor (P-T) and Hargreaves–Samani (H-S) evapotranspiration methods after calibration based on the ASCE (American Society of Civil Engineers)-standardized Penman–Monteith method (the ASCE method includes two reference crops: short-clipped grass and tall alfalfa). The analysis also includes the development of a global grid of revised annual coefficients for solar radiation (Rs) estimations using the respective Rs formula of H-S. The analysis was based on global gridded climatic data of the period 1950–2000. The method for deriving annual coefficients of the P-T and H-S methods was based on partial weighted averages (PWAs) of their mean monthly values. This method estimates the annual values considering the amplitude of the parameter under investigation (ETo and Rs) giving more weight to the monthly coefficients of the months with higher ETo values (or Rs values for the case of the H-S radiation formula). The method also eliminates the effect of unreasonably high or low monthly coefficients that may occur during periods where ETo and Rs fall below a specific threshold. The new coefficients were validated based on data from 140 stations located in various climatic zones of the USA and Australia with expanded observations up to 2016. The validation procedure for ETo estimations of the short reference crop showed that the P-T and H-S methods with the new revised coefficients outperformed the standard methods reducing the estimated root mean square error (RMSE) in ETo values by 40 and 25 %, respectively. The estimations of Rs using the H-S formula with revised coefficients reduced the RMSE by 28 % in comparison to the standard H-S formula. Finally, a raster database was built consisting of (a) global maps for the mean monthly ETo values estimated by ASCE-standardized method for both reference crops, (b) global maps for the revised annual coefficients of the P-T and H-S evapotranspiration methods for both reference crops and a global map for the revised annual coefficient of the H-S radiation formula and (c) global maps that indicate the optimum locations for using the standard P-T and H-S methods and their possible annual errors based on reference values. The database can support estimations of ETo and solar radiation for locations where climatic data are limited and it can support studies which require such estimations on larger scales (e.g. country, continent, world). The datasets produced in this study are archived in the PANGAEA database (https://doi.org/10.1594/PANGAEA.868808) and in the ESRN database (http://www.esrn-database.org or http://esrn-database.weebly.com)

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

PHREEQC hydrogeochemical and geochemical modeling course

This three-day course introduces participants to the modeling of hydrochemical and isotope geochemical processes with PHREEQC-2. The basics will be covered in the first two days, while simulation of isotope fractionation in geochemical models is explained at the final day. Simulation of all major hydrochemical processes will be explained and practiced step-by-step starting from simple systems and going towards more complex integrated cases in the end. The course is designed for people who want to refresh their knowledge on (isotope) hydrochemistry and learn how to construct (isotope) biogeochemical models for their own studies. The course focuses on applications in contaminant hydrogeology and environmental chemistry in groundwater and soils

Natural attenuation processes in the Corona Protocol: application to the "NIT" field site

The contribution of the CORONA project (Confidence in fORecasting Of Natural Attenuation a research project supported by the European Commission under the Fifth Framework Programme) to the theoretical background and application principles of Monitoring Natural Attenuation (MNA) is presented. A detailed knowledge of hydrodynamical, hydrochemical and microbiological processes occurring inside and, particularly, at the interfacial fringe of the plume is put in evidence as the key factor in assessing the natural attenuation potential. The plume zonation (both in horizontal and vertical direction) in areas where different redox processes are acting is possible only with high resolution sampling devices such as Multi Level Samplers (MLSs). As a representative case study the NIT plant is been chosen as test site for the application of the Corona Protocol

Reactive modelling of 1,2-DCA and DOC in a coastal aquifer

1,2-Dichloroethane (1,2-DCA) was found to be the most abundant compound among chlorinated hydrocarbons detected in a petrochemical plant in southern Italy. This site is located near the coastline, and it is set above an unconfined coastal aquifer, where seawater intrusion is present. The presence of organic and inorganic contaminants at this site has required the implementation of remediation strategies, consisting of pumping wells (hydraulic barrier) and a horizontal flow barrier. The purpose of this work was to assess the influence of salt water intrusion on the degradation rate of 1,2-DCA. This was done on a three-dimensional domain relative to a limited portion of a well characterized field site, accounting for density-dependent flow and reactive transport modelling of 1,2-DCA and Dissolved Organic Carbon (DOC). The modelling procedure was performed employing SEAWAT-4.0 and PHT3D, to reproduce the complex three-dimensional flow and transport domain. In order to determine the fate of 1,2-DCA, detailed field investigations provided intensive depth profile information. Different, kinetically controlled degradation rates were simulated to explain the observed, selective degradation of pollutants in groundwater. Calibration of the model was accomplished by comparison with the two different sets of measurements obtained from the MLS devices and from pumping wells. With the calibrated model, it was possible to distinguish between dispersive non-reactive processes and bacterially mediated reactions. In the non-reactive model, 1,2-DCA sorption was simulated using linear sorption coefficient determined with field data and 1,2-DCA degradation was simulated using a first order decay coefficient using literature data as initial guess. Finally, on the reactive transport model, where a two-step approach with partial equilibrium approach was implemented, the effects of neglecting the cation exchange capacity, omitting density-dependent flow, and refining the vertical discretization of the model were investigated. Comparison of results from various scenarios shows that geochemical changes in inorganic constituents can be used to improve the site's conceptual model, and establishes that natural degradation processes can be suitable for 1,2- DCA as a remediation option

Application of intrinsic groundwater vulnerability indices for the agricultural land of Sarigkiol basin – Greece in GIS environment

The assessment of nitrogen losses from agricultural systems and the degree of related groundwater pollution is fundamental to the standards established by the European Community Framework Directive for water protection (WFD). Intrinsic groundwater vulnerability indices, which can describe nitrogen pollution originating from non-point agricultural sources, are a basic tool for the evaluation of agricultural production as based on environmental policies. Many methods exist to describe intrinsic groundwater vulnerability. In this study, the LOS, SINTACS and GOD indices were used to assess the agricultural lands, located in the Sarigkiol basin, Greece. The first method is based on a deterministic approach and regression analysis; while the other two approaches are parametric methods based on empirical ratings and weights. This study presents the strengths and weaknesses of these different groundwater vulnerability indices and the related opportunities and challenges associated with their wide scale application within Greece. The study found significant differences between the results of the three indices and that this could be attributed to the different approaches and parameters used in the calculations. In contrast with SINTACS and GOD, LOS describes the intrinsic vulnerability of the unsaturated zone to release nitrogen to the groundwater but does not take into account groundwater properties (saturated zone). The SINTACS and GOD methods cannot be applied to highland regions, where an aquifer does not exist; and do not take climatologic conditions into account, which tends to change the nitrogen cycle. In comparison, the LOS index can be adapted to different climatic environments. In the SINTACS and GOD methods, uncertainty is increased in the calibration of weights and ratings because it is based on subjective criteria. In comparison, LOS does not need calibration as it uses more detailed data. The LOS index showed preferred performance because it better described the differences between the lower and higher altitude areas, which have different climatic conditions, and it was applied even on the parts of the study area which were far from the main aquifer

From conceptual to numerical modelling of a complex contaminated site in Italy using hydrogeological and hydrochemical characterization

Chemical, geological and hydrogeological investigations were conducted in a polluted site in southern Italy, with the aim of improving and validating a conceptual model of groundwater flow and contaminant transport. The collected data allowed building of a numerical model, which takes into account groundwater flow interaction with salt water intrusion by a density-dependent model. Simulation results agree with field data, showing that the salt wedge intrusion has reached the pumping wells, the dissolved contaminants are completely intercepted by a P&T system and that around 25% of exploited flow comes from losses from a surface seawater canal. Finally the three dimensional flow model was validated by new data collected in 2009, and it is now used to forecast and to manage the pumping rates of more than 70 wells