Search results for "MINERALOGY"
showing 10 items of 1516 documents
The Impact of Grain Size Composition and Organic Matter Content on Magnetic Susceptibility of Anthropogenically Transformed Bottom Sediments, as Exem…
2017
The article presents the results of an analysis of the surface layer of bottom sediments in the naval harbour in Hel. During field work conducted in June 2013, 54 sediment samples were collected. The aim of the study was to examine magnetic susceptibility of harbour sediment as a parameter determining the degree of anthropopressure. As part of laboratory tests, grain size analysis was performed in order to determine organic matter content and magnetic susceptibility of the sediment. The study also measured the impact of environmental factors on fluctuations in the other studied parameters. The results demonstrate increased dynamics of sedimentary environment in the open part of the naval ha…
Air Pollution Research Based on Spider Web and Parallel Continuous Particulate Monitoring—A Comparison Study Coupled with Identification of Sources
2021
Air pollution is monitored mainly in urban or industrial areas, even if it is known that in rural ones, low emission can significantly worsen air quality. Hence, cheap and easily accessible methods of monitoring are needed. Recently, spider webs biomonitoring is getting popular, however, there is no information about its comparison with active methods. In this study, PTEs accumulated on spider webs were compared with results from continuous particulate monitor (CPM). Generally, higher potentially toxic elements concentrations were noted in spider web, with exception in the case of Zn. Zn may be present rather in smaller fractions, hence it needs more time for accumulation on spider web whil…
Inorganic geochemistry of roadway dust from the metropolitan area of Palermo, Italy
2003
Inorganic matter from roadway dust collected in the urban area of Palermo, Italy, was analysed to identify the chemical elements introduced into the environment as a result of human activities. Metals of environmental concern exhibit very high enrichment factors, which in some cases exceed 100. Metal size distribution indicates that Pd, Pt, Au, Sb, Zn, S, Ni, V, Mo and Cr substantially accumulate in the finest particles, whereas Pb, Br, As, Cu, Ag and Ba are almost independent of the size fraction. SEM/EDS analyses revealed that some individual particles contain clusters of foreign particles (<10 μm) made up of Fe-Ni, Cr-Ni or Fe alone, typical of the abrasion of stainless steel. Others are…
Geochemical records of limestone façades exposed to urban atmospheric contamination as monitoring tools?
2008
International audience; Magnetic susceptibility, surface rock soiling, elemental composition and lead isotope ratios were measured in surface stone samples collected at different heights of a late 19th century building in Dijon, France. We targeted four limestone facades that differ in orientation and proximity to car traffic. It seems that zinc, copper, sulphur and cadmium are present as diffuse pollutants in urban atmosphere, at least at the scale of the building studied. In contrast, lead and arsenic exhibit point sources: automotive traffic and past coal-burning fly-ash emissions; both coherent with lead isotopic composition measurements. Parameter variations primarily result from expos…
Use of lichens in detecting environmental risk and in geochemical prospecting
1995
This paper provides data on variations in the contents of As, Sb, Ni, V, Pb, Cu, Cr, Au, Zn, Sc, and Al, measured in the thalli of a saxicolous lichen species,Xanthoria calcicola Ochsner s.l., collected in northeastern Sicily, near an industrial zone and along a belt crossing areas of known ores containing sulfides of heavy metals. A total of 91 lichen samples were collected on roof tiles (39) and on rocks (52). In the industrial zone, analysis of lichen thalli revealed high contents of nickel and vanadium, decreasing at increasing distances from the source of contamination. The results have also revealed the versatility ofXanthoria calcicola in geochemical prospecting for heavy metals such…
Releasing rates of inorganic ions in lichens monitored by capillary zone electrophoresis as indicators of atmospheric pollution
2000
Abstract The releasing rates of inorganic ions in lichens when a thallus sample is sonicated under water, were studied. Ramalina farinacea samples taken from two locations exposed to atmospheric pollution sources at Els Ports (Castellon, Spain), and from three control locations, were used. Samples without visual symptoms of injuries were sonicated from 3 to 6 successive 10-min periods while renewing the water layer in between. Experiments with successive 2-min-sonication periods were also performed. The extracts were analysed by capillary zone electrophoresis, and K + , NH 4 + , Na + , Ca 2+ , Mg 2+ , Cl − , SO 4 2− and NO 3 − were detected. The apparently undamaged lichens sampled at locat…
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…
Occurrence of platinum, palladium and gold in pine needles of Pinus pinea L. from the city of Palermo (Italy)
2003
Abstract Preliminary data on the presence of Pt, Pd and Au in airborne particulate matter from the urban area of Palermo (Sicily, Italy) are presented. They were obtained by analysing 40 samples of pine needles (Pinus pinea L.) collected in and around the city. Observed concentrations range from 1 to 102 μg/kg for Pt, 1 to 45 μg/kg for Pd and 22 to 776 μg/kg for Au. Platinum and Pd concentrations in pine needles are up to two orders of magnitude higher than their crustal abundances. They exhibit a high statistical correlation (R2=0.74) which suggests a common origin. Precious metal concentrations measured within the city centre are much higher than those occurring outside the town. The dist…
Maya Blue as a nanostructured polyfunctional hybrid organic–inorganic material: the need to change paradigms
2009
Maya Blue, an ancient nanostructured organic–inorganic hybrid material resulting from the attachment of indigo, a natural dye, to a phyllosilicate clay, palygorskite, has received considerable attention of late. Despite intensive research, several aspects remain unsolved, in particular the nature of the indigo–palygorskite association. Recent results suggest that the Maya Blue pigment is a complex system in which different topological isomers of various indigoid molecules attached to the palygorskite matrix coexist.
Rheology of Sodium Hyaluronate Saline Solutions for Ophthalmic Use
2007
The aim of this work was to investigate the rheological properties of different saline solutions of sodium hyaluronate (NaHA) with special interest for medical applications. The experimental results were compared with literature data for commercial ophthalmic viscosurgical devices (OVDs) used in cataract surgery. We offer some tools to tailor the rheological behavior of OVDs for different purposes. We have investigated to which extent surgical requirements can be fulfilled by adjusting either the molecular weight of NaHA or its concentration, parameters that are in some respects equivalent but not in others. Furthermore, we demonstrate that moduli and complex viscosities of NaHA saline solu…