Lo studio dei processi biogeochimici che avvengono all’interfaccia acqua-sedimento riveste grande importanza per comprendere quali fattori ambientali siano responsabili di un eventuale modifica nel bilancio del carbonio organico e di altri elementi maggiori o minori e può` fornire un' indicazione su quali siano le aree più sensibili a tali processi. In questo studio sono stati analizzati i meccanismi che guidano la mineralizzazione della sostanza organica in aree caratterizzate da differenti condizioni idrodinamiche, batimetriche e trofiche nel Mediterraneo centrale. In particolare sono state prelevate carote di sedimento e analizzate le acque interstiziali in siti localizzati nell'Adriatico centro-meridionale, caratterizzati da basse profondità, alti tassi di sedimentazione e elevati apporti di sostanza organica, e in siti localizzati nello Ionio centro-settentrionale, caratterizzati da profondità crescenti, minori tassi di sedimentazione e ridotti apporti fluviali. L'analisi dei processi di degradazione della sostanza organica evidenzia differenze regionali tra il bacino adriatico e quello ionico: processi di mineralizzazione ossica e subossica appaiono intensi nei sedimenti adriatici, diversamente il bacino ionico appare caratterizzato principalmente da processi di degradazione ossica della sostanza organica. Inoltre, relativamente ai flussi bentici di Carbonio Inorganico Disciolto (DIC) flussi inversi sono stati registrati nei due bacini: i sedimenti adriatici si comportano come sourse di DIC, mentre i sedimenti Ionici si comportano come dei sink di DIC suggerendo una possibile precipitazione di carbonati nel bacino ionico. / It is known that the burial of organic carbon (OC) in marine sediments is one of the major long-term sinks of reduced carbon on Earth and the long-term sink of particulate OC in marine sediments contribute to moderate atmospheric CO2 levels on geological time scales. For this reason several efforts have been made to understand early diagenetic zonation and evaluate the associated benthic fluxes. In this study we investigate the features controlling the early diagenetic processes in areas of different sedimentation in the central Mediterranean Sea. Sediments core were collected in 7 stations characterized by different bathymetry, hydrological setting and trophic conditions. Northern stations, located in the central and southern Adriatic depressions, are characterized by shallow depths, higher sedimentation rates and higher organic matter inputs. Southern stations, located in the Northern and Central Ionian Sea, are characterized by increasing depths, different provenances of terrigenous sediments, lower productivity, lower sedimentation rates and organic matter inputs. The early diagenesis processes recorded in the Adriatic and Ionian seas showed regional differences between the Adriatic and Ionian basins. Higher inputs of reactive organic matter promote a northern-southern and shallow-deep trend in Adriatic sediments. These sediments are characterized by oxic-suboxic degradation processes and a lowering of remineralization processes in accord with distance from terrestrial inputs is evident. In the Ionian basin the remineralization processes takes place mainly by means of oxic reactions. The inputs of reactive organic matter in this area are lower for the lower productivity of this basin and for the higher distance from fluvial inputs. However, inverse DIC fluxes occur, Adriatic sediments are a net source of DIC while Ionian sediments show a sink of DIC suggesting a possible precipitation of carbonate in the Ionian basin.

Terrestrial radioactivity for most individual is the major contributor to the total dose and is mostly provided by 238U, 232Th and 40K radionuclides. In particular indoor radioactivity is principally due to 222Rn, a radioactive noble gas descendent of 238U, second cause of lung cancer after cigarettes smoking. Vulsini Volcanic District is a well known quaternary volcanic area located between the northern Latium and southern Tuscany (Central Italy). It is characterized by an high natural radiation background resulting from the high concentrations of 238U, 232Th and 40K in the volcanic products. In this context, subduction-related metasomatic enrichment of incompatible elements in the mantle source coupled with magma differentiation within the upper crust has given rise to U, Th and K enriched melts. Almost every ancient village and town located in this part of Italy has been built with volcanic rocks pertaining to the Vulsini Volcanic District. The radiological risk of living in this area has been estimated considering separately: a. the risk associated with buildings made of volcanic products and built on volcanic rock substrates b. the risk associated to soil characteristics. The former has been evaluated both using direct 222Rn indoor measurements and simulations of “standard rooms” built with the tuffs and lavas from the Vulsini Volcanic District investigated in this work. The latter has been carried out by using in situ measurements of 222Rn activity in the soil gases. A radon risk map for the Bolsena village has been developed using soil radon measurements integrating geological information. Data of airborne radioactivity in ambient aerosol at two elevated stations in Emilia Romagna (North Italy) under the influence of Fukushima plume have been collected, effective doses have been calculated and an extensive comparison between doses associated with artificial and natural sources in different area have been described and discussed.

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