Flavia Ferranti

Geochemical modeling and multivariate statistical evaluation of trace elements in arsenic contaminated groundwater systems of Viterbo Area, (Central Italy).

Contamination of groundwater by naturally occurring arsenic has recently become a disturbing environmental problem in Viterbo area, Central Italy. Arsenic concentrations in most of the public supply networks exceed the maximum allowable limit of 10 μg/l (WHO) for drinking water. The primary purpose of this paper is to obtain a better understanding of the factors contributing to the high levels of As in water supply networks. This study focuses on (a) the determination of basic hydrochemical characteristics of groundwater, (b) the identification of the major sources and processes controlling the As contamination in public supply networks, (c) to find out possible relationships among the As and other trace elements through principal component analysis (PCA). Groundwater samples from public water supply wells and springs were collected and analysed for physico-chemical parameters and trace elements. Springs and well water samples are predominantly of the Na–HCO3, Na –Ca–HCO3 and Ca–HCO3 types and the highest arsenic concentrations were observed in Na–HCO3 type water. Eh-pH diagrams reveal that H2AsO4− and HAsO42−, As(V) arsenate, are the dominating As species highlighting slightly to moderately oxidizing conditions. Geochemical modeling indicates that arsenic-bearing phases were undersaturated in the groundwater, however most of the samples were saturated with respect to Fe (i.e. magnetite, hematite and goethite) and Al (diaspore and boehmite) oxide and hydroxide minerals. Concentrations of As, Li, B, Co, Sr, Mo, U and Se are highly correlated (r > 0.7) with each other, however in some groundwater samples As show also good correlations (r > 0.5) with Fe and Mn elements reflecting the relationships among the trace elements result from different geochemical processes. Evaluation of the principal component (PCA) analysis and geochemical modeling suggest that the occurrence of As and other trace element concentrations in groundwater are probably derived from (i) weathering and/or dissolution of volcanic source aquifer materials and (ii) adsorption/desorption processes on the Fe and Al oxide and hydroxide minerals.

Environmental Impact of a Motorway Tunnel Project on an Important Karst Aquifer in Southern Latium Region: The Case of Mazzoccolo Spring (Formia, Italy)

Due to the heavy traffic problems in Formia downtown, a motorway project was designed to reduce traffic congestion in the fastly growing city. The proposed motorway passes over one regionally an important karst aquifer feeding Mazzoccolo spring, in the southeast part of Latium Region. This paper deals with the analysis of the most important environmental impacts on this vulnerable karst aquifer and, as a consequence, on groundwater coming out form the Mazzoccolo Spring, which feeds one of the most important drinking water supply network in South Latium Region. A multisystem approach has been applied for vulnerability analysis using SINTACS method. The climatic, topographic, geomorphological and hydrogeological data and field investigations of previous works has been employed. On the other hand, this approach was also evaluated by geochemical and isotope tracers techniques of groundwater samples for the identification of environmental impacts. According to the proposed project, the Motorway tunnel has a significant environmental impact, on the vulnerability of the karst aquifer and hence, on the water supply networks. Thus, based on these analyses the highway investment strategy adapted to Variant of the SS 7 (Appian Way) project should ensure the protection of groundwater resources designing a new variant route avoiding the construction of Mola Mountain tunnel.

Vulnerability Assessment of Mazzoccolo Spring Aquifer (Central Italy), Combined with Geo-Chemical and Isotope Modeling

The present study deals with the characterization of Mazzoccolo karst spring which feeds the most important water supply network in southern part of Latium region, in Central Italy. During sample collections from 2006 to 2008, a series of in situ measurements were conducted for pH, electrical conductivity (EC), total dissolved solids (TDS) and temperature. The environmental isotopic and hydrochemical measurements were carried out for the vulnerability assessment and geochemical modeling with the aim of achieving (i) proper management and protection of this important resource, (ii) hydrochemical processes controlling the evolution of groundwater and (iii) identification of recharge areas. All sampled spring waters are characterized as Ca-HCO3 type waters reflecting the main rock types in the area investigated, where limestones and Pliocene conglomerates are the most dominant formations. The electrical conductivity (EC) and TDS values of water samples from springs varies from with a maximum value of 341 µS/cm and 268 mg/l and minimum value of 28 µS/cm and 104 mg/l, respectively. The pH values of spring samples range from 7.4 to 9 indicating alkaline nature. The anion composition is quite stable showing HCO3 −>Cl−>SO4 2− (in mg/l), while calcium is the dominant cation, followed by magnesium, sodium and potassium. The comparison of δ18O and δ2H values of spring water samples with meteoric water lines shows that most of the samples fall to the Local Meteoric Water Line suggesting input to local rain-fall derives from the Mediterranean Sea. The elevation of the recharge areas range between 600 and 800 m a.s.l confirming the Aurunci karst aquifer is feeding Mazzoccolo spring.

Un approccio integrato al Piano di Monitoraggio Ambientale della sorgente Pertuso (Alta Valle del Fiume Aniene)@@@An integrated approach to the Environmental Monitoring Plan of the Pertuso spring (Upper Valley of Aniene River)

Quantitative assessment of groundwater and surface water is an important tool for sustainable management and protection of these important resources. This paper deals with the design of a multi-disciplinary monitoring plan related to the catchment project of the Pertuso spring, in the Upper Valley of Aniene River, which is going to be exploited to supply an important water network in the South part of Roma district. According to the Legislative Decree 152/2006, as modified by DM 260/2010, any infrastructure design should take in consideration an Environmental Monitoring Plan for the hydrogeological settings of the study area. Thus, the hydrogeological characterization combined with an Environmental Monitoring Plan provides to evaluate the potential adverse environmental impacts due catchment works. For water resources assessment and management, the quantification of groundwater recharge is a preliminary step. As a matter of fact, it has been included the quantitative characterization of the Pertuso spring, in the aim of to protect catchment area, which is directly affect by the natural hydrogeological balance of this aquifer. Thus, a multi-disciplinary monitoring plan has been set up, including quantitative and hydrogeochemical measurements, both for groundwater and surface water of the Upper Valley of Aniene River. The target of this Environmental Monitoring Plan is to set up the background framework on the hydromorphological, physico-chemical and biological properties of water resources in the water basin influenced aim by any potential environmental impact due to the construction activities. The Environmental Monitoring Plan and main features of the monitoring network will be presented in this study.