Search results for " sedi"

Heavy metals in rivers of Latvia☆

2000

Abstract Total heavy metal concentrations in waters and sediments (HNO 3 digestible Pb, Cu, Co, Ni, Mn, Zn) and their speciation forms in sediments (exchangeable, carbonate bound, iron–manganese oxide bound, organic matter bound and residual) in major and common small watercourses (31 sampling stations) along their flow in Latvia were determined. The metal loads entering the Baltic Sea from Latvia were calculated. Increased metal concentrations were found only in lower reaches of the largest rivers and locally around known industrial pollution sources. Differences in metal concentrations and loads in rivers from different regions of Latvia were related to natural geochemical processes. Meta…

Distribution of Heavy Metals in Marine Sediments of Palermo Gulf (Sicily, Italy)

2008

Concentrations of Cr, Cu, Hg, Pb and Zn have been measured, by atomic absorption spectrophotometry, in the fine fraction (<63 μm) of surface sediments collected in 30 sites in the Palermo Gulf (Sicily, Italy) in order to assess the levels and the spatial distribution of these elements. Enrichment factors calculated with respect to clean areas have been considered to discriminate between levels due to background or to pollution contributions. The sampling stations, which form a grid inside these areas, are characterized by geographic proximity and by the presence of pollution sources. Ratio matching technique along with hierarchical clustering, minimum spanning tree and principal component a…

Composition, distribution, and sources of polycyclic aromatic hydrocarbons in sediments of the gulf of Milazzo (Mediterranean Sea, Italy)

2014

This article describes the characterization of Polycyclic Aromatic Hydrocarbons (PAHs) in sediments of Milazzo Gulf (Italy) located in front of an oil refinery and a power plant. The investigated area is characterized by urban and industrial activities. The sixteen PAHs identified by the USEPA, as requiring priority monitoring, and other non USEPA listed PAHs, namely perylene and some methyl derivatives, were investigated The total PAHs concentrations, expressed as ∑ 19 PAH ranges from 5.6–7402 μg/Kg d.w., with a mean value of 492 μg/Kg d.w. The concentrations of PAHs found in 64 out of 67 samples were lower than the effect range low (ERL = 2460 μg/Kg) concentration, while the remaining sam…

Chemistry, mineralogy and radioactivity inposidonia oceanicameadows from North-Western Sicily

2004

This paper presents measurements of major, minor, metal trace elements and radionuclides in sediments and in Posidonia oceanica samples from north-western Sicily (Italy). The mineralogical and chemical composition of sediments were determined by X-ray diffraction and X-ray fluorescence techniques, respectively. A flame atomic absorption spectrophotometry was used to measure concentrations of Cu, Zn, Cd and Pb in P. oceanica samples and in sediments. Specific activities of selected radionuclides have been determined by high-resolution gamma spectrometry. Standard statistical analysis was used to assess correlations between different elements and different sample types.

Trace metals in “Posidonia oceanica” seagrass from south-eastern Sicily

2005

Heavy-metal concentrations were measured in sediments and tissues of Posidonia oceanica seagrass from south-eastern Sicily (Italy) in order to assess the degree of metal pollution in the coastal area. Seagrasses and sediments were collected at four sites along the south-eastern coast of Sicily. Flame atomic absorption spectrophotometry (FAAS) was used to measure concentrations of Cu, Zn, Cd and Pb. Standard statistical analyses were used to assess significant differences among the levels of the elements measured in different tissues and sediment and spatial distribution. The greatest values of potentially toxic metal concentrations were observed at the station near the industrial sites of A…

Volcaniclastic Deposition and migration of basin depocentres after the eruption of the Neapolitan Yellow Tuff: The Pozzuoli Bay (Naples, Italy)

2012

The Campi Flegrei is an active caldera located on the coastal zone of SW Italy (Fig. 1), close to the town of Naples Bay, that has been characterized by explosive activity and unrest throughout the Late Quaternary. This area represents a very active segment of the Eastern Tyrrhenian margin and may be regarded as an ideal laboratory to understand the mechanisms of caldera dynamics and the interplay between volcanism, tectonics and sedimentary processes along a continental back-arc margin. Recent research at Campi Flegrei has shown that a significant part of the offshore volcaniclastic products and structures, the late-stage geodynamic evolution of the inner caldera resurgence and the stratal…

SULLA APPLICABILITÀ DELLA USLE-MM PER LA STIMA DISTRIBUITA DELLA PRODUZIONE DI SEDIMENTI

2010

Nella memoria è presentata una nuova versione del modello distribuito SEDD (SEdiment Delivery Distributed model) che accoppia la RUSLE o la USLE-MM con un criterio spazialmente distribuito per la stima dei processi di trasferimento delle particelle erose all’interno di un bacino idrografico. In particolare, viene proposta l’applicazione a scala di bacino di un fattore di erosività, che tiene conto anche del processo di deflusso a scala di versante, e di un fattore di erodibilità del suolo determinati utilizzando le misure parcellari condotte nell’area sperimentale di Sparacia in Sicilia. Il modello è stato calibrato utilizzando le misure dei deflussi liquidi e solidi effettuate nei bacini s…

Foglio 619, Santa Margherita di Belice

2013

Clinical characteristics of COVID-19 patients in Latvia under low incidence in Spring 2020

2020

ABSTRACTBackgroundCOVID-19 is a new infectious disease with severe disease course and high mortality in some groups. Blood tests on admission to the hospital can be useful for stratification of patients and timely correction. Our study investigated the clinical features of COVID-19 patients in Latvia and differences in blood tests in groups with different disease severity.MethodsThe retrospective study included 100 patients hospitalized in Riga East Clinical University Hospital in Spring 2020. The severity of the disease course was classified by the presence of pneumonia and its combination with respiratory failure. We have assessed blood cells’ count, hemoglobin, hematocrit, erythrocyte se…

Mineralogical and Chemical Records of Icelandic Dust Sources Upon Ny-Ålesund (Svalbard Islands)

2018

This work aims to identify the geochemical and mineralogical markers of Icelandic dust and to differentiate it from the dust of local origin deposited at the Ny-Ålesund station. We characterized representative sediment samples from Iceland and Svalbard and compared them to a set of aerosol samples collected in Ny-Ålesund to check the existence and type of the mineralogical markers. The sediment samples were analyzed by X-ray diffraction (XRD) to detect the mineralogical constrain of the geochemical markers. Both aerosol and sediment samples were examined by scanning electron microscopy coupled with EDS microanalysis (SEM-EDS) and image analysis to detect and to provide a morpho-chemical cha…