1,721,271 research outputs found
Geochemical investigations on the shales of the Frido Unit (southern Italy): a key to early Jurassic evolution of the Tethyan Ocean.
No full textThe phreatic water system of Vulcano, Aeolian Island: time-variations of chemical and isotopic parameters.
No full textThe Arno river catchment, northern Tuscany: chemistry and sulfur isotopes of waters and sediments from Elsa and Era river sub-basins
No full textSpatial distribution of elements in near surface sediments as a consequence of sediment origin and anthropogenic activities in a coastal area in northern Italy
Full text linkThe study reports the results of a geochemical survey in a coastal area of northern Italy with focus on the distribution of chemical elements in near surface sediments as result of both sediment origin and anthropogenic activities. In addition to emphasizing the source-to-sink element dynamics in the area, the main purpose of this paper is to ascertain if anthropic presence could have altered the composition of near surface sediments in urban and industrial areas. We considered 173 sampling sites, and collected soil material from a depth of 90–110 cm. Major and trace elements assessment on milled 2 mm fraction was conducted using WDXRF for Al, As, Ba, Ca, Ce, Co, Cr, Cu, Fe, K, La, Mg, Mn, Na, Nb, Ni, P, Pb, Rb, Si, Sr, Th, Ti, V, Y, Zn and Zr. In addition, Loss On Ignition (LOI) was determined. Principal component analysis (PCA) and cluster analysis (CA) were performed for data interpretation. The distribution of element concentration is heavily related to sediment origin. The major presence of Al, Fe, K, LOI, Mg, Nb, Rb and V characterizes alluvial plain sediments. These materials of Apenninic origin have a finer texture and a major presence of carbonates in respect to the other sediments of the area. Coastal sediments display a general wider range of variation in element concentrations (i.e. Al, Ca, Cr, K, Mg, Mn, P, Si, Ti and Zr) due to a dual origin. In particular, the greater Cr, Mn and Zr content is related to sediments enriched by heavy minerals (e.g. garnet, chromite, zircon) of Alpine origin, while the lesser concentrations trace back to Apenninic origin. Near surface sediments of urban and industrial areas always contain higher Cu, Pb and Zn concentrations with respect to the same sediments not impacted by urban and industrial settlements. This is likely a consequence of the movement of materials made by men over the last 2000 years. These results suggest that the adopted depth of sampling for the calculation of background values might need to be increased in urban and industrial areas to reach unaltered near surface sediments
Geochemical analysis of the upper shoreface sediments between Livorno and the Serchio River (Tuscany): a focus on heavy metals
No full textThis study, conducted in collaboration with the Geologica! office of Province of Pisa, was
carried out in order to assess the spatial distribution of some heavy metals of environmental
relevance (Cr, N i, Pb, Zn, Cu) in near-surface (1 0-20 cm deep) coastal marine sediments (upper
shoreface), collected along the coastline of the province of Pisa, between the Serchio River and
Livorno (northern part of Tuscany, ltaly).
The research enabled the evaluation of the quality status of the near-surface sediments,
allowing the identification of the various sources of heavy metal on the marine basin.
The samples were collected along the upper shoreface at 1 m of water depth over 25 km of
coast. T o evaluate the possible variation of distribution of the heavy metal with the water depth, the
sampling was extended also to six transects normal to the shore up to -10m. Moreover, sediments
from the rivers (Serchio, Arno and Scolmatore canal) feeding the studied area were sampled and
analyzed. Finally, samples from analogous depositional environment dating back to the Holocene
and obtained through continuous cores were included in the study as representative of the natural
background values.
The geochemical analyses provided for ali samples an evaluation of the total concentration
of Cr, Ni, Pb, Zn, Cu by X ray fluorescence spectrometry, that offered information also on other
chemical elements (Si02, Ti02, AI20s, Fe20s(tot)• MgO, MnO, CaO, Na20, K20, P205, Se, V, Rb, Sr,
Y, Zr, Nb, Ba, La, Ce, Th). On some samples (marine, fluvial and borehole), an acqua regia
digestion coupled to ICP-AES analysis has been performed. This analytical method allows the
direct comparison to the thresholds quality imposed by the legislation currently in force (DM
367/2003).
The results suggest that for ali the heavy metals (except Cr) a grain-size control is relevant
with the highest concentrations in the samples with more abundant fine fraction. Cr appears at
particularly high values (51-484 ppm Cr) in the section between the mouths of the rivers Arno and
Serchio due to the selective deposition of heavy minerals. Zinc concentrations are not unusual
within sandy sediments (24-56 ppm Zn), with the highest values observed near Tirrenia an d up t o
the mouth of the Scolmatore canal. Marine sediments do not evidence particularly high values for
Ni (23-58 ppm), Pb (11-28 ppm) and Cu (5-15 ppm) with a limited dispersion of the data. On the
contrary, ali the examined metals display high concentrations in the fine-grained fraction of river
sediments. However, they are transported and accumulated offshore beyond the isobath of 1Om,
not compromising the quality of the analyzed coastal sediments, which are on average composed
of fine or very fine sands.
Core sediments were used to calculate reference values used in the calculation of the
Enrichment Factor (EF=[Me/AI]sample/[Me/AI]reference). The element with more frequent high values
(EF> 1.4) is Cr: they occur from the estuary of the Serchio up to Tirrenia and partly at the mouth of
Scolmatore, and are believed to be mainly originated by natural processes, such as current
dynamics. This leads to an enrichment in Cr-rich heavy metals, that analogously to N i is contained
in ultramafic rocks (ophiolites) outcropping along the drainage basins especially of the Arno River.
High EF for Zn occur at the mouth of the Scolmatore and the village of Tirrenia and could be
related to anthropogenic sources.
Furthermore, although data of pseudototal concentrations (ICP-AES analysis) show that Cr
total and Ni exceed the quality threshold (respectively of 50ppm and 30ppm) in samples from the
beach and from the rivers, the same high value observed in the background samples deriving by
continuous cores (average of pseudototal concentrations of Cr is 67ppm and of Ni is 48ppm)
suggest the existence of high natural background concentrations for Cr and Ni in the examined
area
Life Charting dei disturbi affettivi ricorrenti: Una guida completa alla valutazione clinica di Leverich GS e Post RM
No full textGeochemical and magnetic data on anthropogenic ashes from municipal solid waste incineration (MSWI)
Full text linkThis paper reports supplementary information to “Understanding room-temperature magnetic properties of anthropogenic ashes from municipal solid waste incineration to assess potential impacts and resources” [1]. The sample-set is composed of 47 samples of bottom (BA) and fly (FA) ashes from Municipal Solid Waste Incineration (MSWI), including eight magnetic extracts of selected BA and FA materials. The sampling relies on a simple random sampling strategy at four different MSWI sites in Northern Italy [2]. X-Ray Fluorescence (XRF) analysis on pressed powder pellets, microscopic observations on thin sections and stubs, and magnetic analysis were carried out. Various magnetic measurements are presented: the magnetic susceptibility measured at two different frequencies (0.47 and 4.7 kHz); the mass-specific susceptibility of ARM (χARM), expressed in m3/kg, calculated after mass-normalization and bias DC field correction; experiments for isothermal remanent magnetization (IRM) experimented were also conducted. The latter measurement allowed the calculation of additional parameters, such as the coercivity of remanence (B0cr) and the S-ratio [3]. The IRM acquired in a field of 1.0 T was regarded as the saturation IRM (SIRM). Mass-specific magnetic susceptibility (χ) was calculated by dividing the volume susceptibility by the sample mass. Finally, hysteresis loops and backfield curves at room temperature were measured on selected samples and are available. Data can be reused as groundwork information in future studies on MSWI residues. It would be essential to produce new data on geochemical and magnetic characteristics of MSWI residues to assure good coverage of data for enhanced sustainability of these heterogeneous streams of anthropogenic materials. This combination of methods will contribute to paving the way for quick and reliable resource assessment as well as to promote environmental sustainability
Weathered biotites from granitoids: the fractionation of REE, Th and transition elements and the role of accessory and secondary phases
No full textGeochemical evidence for fluid-rock interaction along high angle faults in the Alpi Apuane, NW Tuscany, Italy,
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