Giancarlo Rampazzo

Temporal variability and effect of environmental variables on airborne bacterial communities in an urban area of Northern Italy

Despite airborne microorganisms representing a relevant fraction of atmospheric suspended particles, only a small amount of information is currently available on their abundance and diversity and very few studies have investigated the environmental factors influencing the structure of airborne bacterial communities. In this work, we used quantitative PCR and Illumina technology to provide a thorough description of airborne bacterial communities in the urban area of Milan (Italy). Forty samples were collected in 10-day sampling sessions, with one session per season. The mean bacterial abundance was about 104 ribosomal operons per m3 of air and was lower in winter than in the other seasons. Communities were dominated by Actinobacteridae, Clostridiales, Sphingobacteriales and few proteobacterial orders (Burkholderiales, Rhizobiales, Sphingomonadales and Pseudomonadales). Chloroplasts were abundant in all samples. A higher abundance of Actinobacteridae, which are typical soil-inhabiting bacteria, and a lower abundance of chloroplasts in samples collected on cold days were observed. The variation in community composition observed within seasons was comparable to that observed between seasons, thus suggesting that airborne bacterial communities show large temporal variability, even between consecutive days. The structure of airborne bacterial communities therefore suggests that soil and plants are the sources which contribute most to the airborne communities of Milan atmosphere, but the structure of the bacterial community seems to depend mainly on the source of bacteria that predominates in a given period of time.

Role of desert aerosol in metal fluxes in the Mediterranean area.

The chemical composition of aerosols and precipitation collected over Sardinia primarily reflect Saharan and European inputs. European background aerosols in Sardinia show a 3- to 25-fold decrease in EF crust values for Cd, Zn, Pb, and Cr compared with coastal stations in the Western Mediterranean. Partitioning of total atmospheric deposition between soluble and insoluble phases shows that Al, Si, Fe and Pb originating from the atmosphere are mostly in an insoluble form. For Ca, Cd and Cr metals, the dissolved fraction represents 50-90% of the total input. Aerosol dissolution experiments performed at particle concentrations ranging from 3 to 300 mg l -1 show that Cd and Pb have low solubilities at high mass particle concentrations. The solubility of Pb increases with EF crust values and the finest grain-size of the aerosols (<1μm), and is also affected by pH. Dissolution of Al and Fe decreases significantly from 30% (13% for Fe) at aerosol loads lower than 5 mg l -1 to less than 1% for both metals at total aerosol concentrations greater than 100 mg l -1 . The fluxes (dry + wet) of metals in Sardinia show that ∼ 30% of the Cd and Pb to more than 80% of the Fe and Al come from the Sahara.

Measurement of atmospheric deposition of polychlorinated dibenzo-p-dioxins and dibenzofurans in the Lagoon of Venice, Italy

Data on atmospheric fall-out of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) were provided by collecting bulk deposition in four stations inside the Lagoon of Venice. A total of 44 monthly samples was collected during the period July 1998-July 1999 in one site near an industrial area (Porto Marghera), one site in the city of Venice, and two sites in the southern- and northernmost ends of the Lagoon. Fluxes of PCDD/Fs were between 0.1 and 470 pg m(-2) d(-1), corresponding to 0-9.2 pg of 2,3,7,8-TCDD equivalents (TEQ) m(-2) d(-1), with a gradient increasing from remote to urban/industrial stations. Thus, annual deposition of PCDD/Fs to the Lagoon (total area=550 km2), calculated with various methods, turned out to be approximately 12 g, corresponding to approximately 400 mg TEQ. Significant differences were found among the stations, with a clear fingerprinting signature (PCDF/PCDD>1) of the deposition collected near Porto Marghera, and a reversed pattern (PCDF/PCDD<1) in the rest of the Lagoon, which pattern was similar to the sediments collected in the same locations. Lastly, the amount of bulk sigmaTEQ of all stations was compared with the guide values for dioxins in depositions proposed by De Fré et al. [Organohalogen Compounds 45 (2000) 324].

Characterization of PM10 sources in a coastal area near Venice (Italy): An application of factor-cluster analysis

In this study a factor-cluster analysis (FCA) applied to chemical composition of atmospheric particulate matter was carried out. Relating specific wind data and back-trajectories to the daily samples grouped using FCA can be useful in atmospheric pollution studies to identify polluting sources and better interpret source apportionment results. The elemental composition and water soluble inorganic ions content of PM(10) were determined in a coastal site near Venice during the sea/land breeze season. From the factor analysis four sources were identified: mineral dust, road traffic, fossil fuels and marine aerosol. From a hierarchical cluster analysis, applied on the factor scores, samples with a similar source profile were grouped. Five clusters were identified: four with samples highly characterized by one identified source, one interpreted as general background pollution. Finally, by interpreting cluster results with wind direction data and back-trajectory analysis further detailed information was obtained on potential source locations and possible links between meteorological conditions and PM(10) chemical composition variations were detected. The proposed approach can be useful for air quality assessment studies and PM(10) reduction strategies.

Geochemical characterization of PM10 emitted by glass factories in Murano, Venice (Italy)

The atmosphere in Venice, like in other European cities, is influenced by complex PM(10) multi-emission sources with a net tendency to exceed the limits fixed by the directive 99/30/EC. This study investigated the composition of an ensemble of similar industrial sources, the Murano Glassmaking Factories (MGFs), and their influence on the Venice air quality, using a modelling approach, statistical analysis and geochemical considerations. Preliminary modelling simulations were conducted to select three sampling sites along the way of preferential transport of pollutants from source between February and April 2003. Subsequently, a sampling campaign was carried out in the same period of simulations. Concentrations of PM(10), eight major elements (Al, Ti, Ca, Mg, Na, K, Fe, Mn), 20 minor and trace elements (Li, V, Cr, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Ru, Rh, Cd, Sb, Ba, Ce, Pt, Pb) and four PAHs (BaA, BbF, BkF, BaP) were quantified. The analytical results were statistically processed for exploring the relationships between inorganic elements and organic compounds, and results were interpreted using geochemical considerations. Results show a MGF component of PM(10) characterised by two different fingerprints: the first linked to glass raw material composition and the second mainly related to glass additives. Particularly, Cd, Se, As and Li preserve their ratios in all study area, and are interpreted as principal components of the MGF emissions. Other fingerprints can be traced to urban sources from the Venetian mainland.

Los ostràcodos actuales de la laguna de Venecia (NE de Italia)

In the Venice lagoon, ostracods from 99 recent samples were studied. The biocoenosis is more abundant in the inner margin, near some little channels. The microfaunal analysis delimited three estuarine associations, with numerous valves of Cyprideis torosa, and one marine association (Pontocythere turbida). Salinity, hydrodynamics, nutrients and substrate are the main factors which control the distribution of these microorganisms. This distribution is very similar in other recent lagoons of Italy.

SULPHIDE SPECIATION IN SURFACE SEDIMENTS OF THE LAGOON OF VENICE : A GEOCHEMICAL AND MINERALOGICAL STUDY

Abstract Three 1-m cores of recent sediments from the Lagoon of Venice were sampled to obtain the vertical distribution of Fe, Zn, Cu, Pb and Cd, and to study authigenic iron sulphides from the geochemical and mineralogical viewpoints. Zn, Cu, Pb and Cd occur in superficial sediments in concentrations many times higher than those of their natural background; the existence of ZnCd and CuPb couples were revealed by their very similar depth profiles. The latter couple is also closely correlated with sulphide-sulphur. Iron is characterized by quite a different behaviour, showing a sharp increase at a depth of 35 cm. From a geochemical viewpoint, authigenic sulphides were distinguished into pyrite and Acid Volatile Sulphides (greigite and mackinawite). Their distribution is characterized by high concentrations of AVS in the first 25 cm of sediments, dramatically decreasing with depth. Pyrite, present in lower amounts, shows the opposite trend, although in one core both species were present in comparable amounts. Mineralogical study of the heavy mineral fraction revealed that the iron sulphides are composed of pyrite (organised both in the classic framboidal growth and in unordered micro-crystal swarms) and iron “mixed sulphide” aggregates, with variable optical patterns and colloform, botroidal or massive growth. No heavy metals were detected in the crystalline lattice of the sulphides. Down to 25 cm all types of sulphides occur, and with increasing depth pyrite clearly prevails. This behaviour may have various causes, e.g. chemico-physical control by specific microniches, temporal and spatial variations favouring the formation of different types, evolution of iron mixed sulphides into more stable forms.

Geochemical considerations on trace element distributions in suspended matter and sediments at the river-sea interface, Adige River mouth, northern Adriatic sea

Abstract The particulate matter at the Adige River mouth has been investigated in order to determine the natural geochemical processes in the estuarine environment, and the anthropogenic influence on the biogeochemical cycling of heavy metals. The determination of suspended matter and sediment physico-chemical characteristics (grain size, mineralogy, organic matter content, specific surface area), and of concentrations of major and trace elements in the Adige River mouth in different hydrological conditions, has shown that this mouth acts as a trap for most heavy metals. Heavy metals were found to be preferentially bonded to the particulates, and in the estuarine mixing zone scavenging of most dissolved metals occurs, due to salinity and pH gradients, and to the formation of new particulate organic matter. The surface characteristics of suspended particulate matter [fine grain size, abundance of clay minerals, large specific surface area (SSA), organic and inorganic coatings] favour the adsorption of heavy metals. The sedimentation pattern (rapid deposition due to flocculation of fine particles, and to low environmental energy and estuarine circulation) causes accumulation of particulate matter, enriched in heavy metals, in the prodelta zone. Moderate anthropogenic influence on Cu, Pb, Cd, and Cr concentrations has been recognised in the Adige River. The environmental fate of these elements is determined by the same natural processes, and therefore accumulation in front of the river mouth occurs. The elevated partitioning in the organic phase of the anthropogenically influenced elements, could favour their mobility in different environmental conditions.

Sedimentation of riverborne material in a shallow shelf sea: Adige River, Adriatic Sea

Fast sedimentatio of fine grained riverborne suspended matter occurs in the prodelta zone of the Adige River mouthdue to deceleration of river flow and spreading into the low-energy environment in front of the river mouth. Process is probably associated with flocculation processin brackish water.

Biogeochemistry, grain size and mineralogy of the central and southern Adriatic Sea sediments: a review

This review aims to present the current status of studies on geochemical (major minor and trace elements), biochemical (total organic carbon, total nitrogen, isotopic carbon composition, Bacteria, Archaea, phytopigments, proteins, carbohydrates, lipids, humic and fulvic acids), mineralogical (light and heavy minerals, clay minerals) and pollutant (trace metals, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, pesticides, organic stannic compounds) parameters, grain-size composition and sediment–water interactions (early diagenesis and benthic fluxes) for the bottom sediments of the central and southern Adriatic Sea. The review highlighted gaps in or completeness of the parameters needed for research, of areas in which the parameters were investigated, as well as the interdisciplinary nature of the studies. In general, biogeochemical, mineralogical, grain-size and pollutant studies in the central and southern Adriatic Sea are restricted to limited areas, consider only single parameters without an interdisciplinary approach and, except for some more recent projects, are predominatly out of date. On the whole, there is a lack of an organised study concerning the various parameters for the entire central and southern Adriatic Sea and their evolution over time.