25 research outputs found
HEAVY METALS IN STREAM SEDIMENTS AFFECTED BY A LANDFILL AND ASSOCIATED IMPACT ON GROUNDWATER QUALITY
Sanitary landfill facilities are essential to modern societies as repositories for municipal solid wastes. However, they always entrain a certain risk of environmental impact. For this reason monitoring is essential to their operation. In the present work, the environmental impact of such a landfill is studied. Soil samples were collected in and around the landfill and their mineralogy was studied. Top layers of stream sediments were collected to examine possible dispersion of pollutants in the environment. Chemical analyses showed enrichment in As, Cu, Zn, and Pb in the stream sediments compared to uncontaminated samples. The presence of anions such as chloride, sulphate and phosphate adsorbed on clay minerals suggest the interaction of stream sediments with run-off water from the landfill. The groundwater near the landfill site was characterised as not potable and not suitable for irrigation purposes, because some parameters such as NO3 - and Cl- were close or exceeded the permissible limits given by EE, EPA and WHO
Chromium and Nickel distribution in sediments of a coastal area impacted from metallurgical activities: the case of the Larymna Bay
In the present study, the distribution of Cr and Ni was investigated in the surface sediments from the Larymna Bay (Northern Evoikos Gulf) and in metallurgical slag samples discharged in the marine environment. The results were compared to concentrations of Cr and Ni in parent rocks that outcrop extensively in the catchment area of N. Evoikos in order to distinguish natural and anthropogenic sources of these two elements. Elevated concentrations of Cr and Ni as well as high values of magnetic susceptibility were determined in all samples. Low leachability was determined for Cr since chromite is the major crystalline phase of Cr in the samples analyzed whereas higher leachability was observed for Ni
GEOMORPHOLOGY, SEDIMENTOLOGY AND GEOCHEMISTRY IN THE MARINE AREA BETWEEN SIFNOS AND KIMOLOS ISLANDS, GREECE
Στην ελάχιστα μελετημένη θαλάσσια περιοχή μεταξύ των νησιών Σίφνου και Κιμώλου πραγματοποιήθηκε μια εκτεταμένη ωκεανογραφική μελέτη, με σκοπό την καταγραφή της υποθαλάσσιας μορφολογίας και των χαρακτηριστικών των επιφανειακών ιζημάτων, καθώς και της πηγής προέλευσης αυτών. Έγιναν καταγραφές με πολυδεσμικό βυθόμετρο και δειγματοληψίες επιφανειακών ιζημάτων με box corer με το Ω/Κ Αιγαίο και ακολούθησαν αναλύσεις μεγέθους κόκκων, ορυκτολογίας και γεωχημείας. Ένα μεγάλο βαθυμετρικό βύθισμα εντοπίστηκε βόρεια της Κιμώλου, με μέγιστο βάθος 743 μ., που συγκεντρώνει λεπτόκοκκα ιζήματα. Η κατανομή των ιζημάτων ως προς το μέγεθος κόκκων χαρακτηρίζεται από σταδιακή μείωση του μεγέθους από νότο προς βορρά. Η ορυκτολογική σύσταση περιλαμβάνει ασβεστίτη, Mg-ασβεστίτη, αραγωνίτη, δολομίτη, χαλαζία, Κ-άστριους, πλαγιόκλαστα, αμφίβολους και αργιλικά ορυκτά. Οι κύριες ιζηματολογικές επαρχίες που αναγνωρίστηκαν είναι 1) η ρηχή περιοχή πλησίον της Κιμώλου, με υψηλό περιεχόμενο σε Si, Al, K, Rb και Ba, 2) η βαθιά περιοχή δυτικά της Σίφνου, όπου εμφανίζεται και το μεγάλο βύθισμα, που χαρακτηρίζεται από υψηλό περιεχόμενο σε Fe, Ti, Na, Mg, S, Cr, Cu, Ni, V, Zn και 3) το στενό μεταξύ Σίφνου και Κιμώλου, με υψηλότερο περιεχόμενο σε Ca, S και Sr. Στο βύθισμα αυτό, παρατηρήθηκε σημαντικός εμπλουτισμός των ιζημάτων σε μαγγάνιο, ενώ τα οξείδια του Mn φαίνεται να προσροφούν διάφορα μέταλλα.An extensive oceanographic survey was conducted in the marine area between Kimolos and Sifnos Islands, a rather poorly-studied sector of the Aegean Sea, in order to gain better understanding of submarine geomorphological features and associated sediment provenance. Multi-beam bathymetry and surface sediment sampling with a box corer were carried out on board R/V Aegaeo, followed by grain-size analysis, XRD and XRF measurements. A large circular depression was identified north of Kimolos reaching a water depth of 743 m, filled with fine grained sediments. Surface sediment distribution is characterized by gradual decrease in grain-size from silty sand to silt in a S-N direction. The mineralogical composition comprises calcite, Mgcalcite, aragonite, dolomite, quartz, K feldspars, plagioclase, amphiboles and clay minerals. Major sediment provinces identified were: (i) the shallow sector proximal to Kimolos, characterized by higher contents in Si, Al, K, Rb and Ba; (ii) the deep area west of Sifnos, including the large depression, characterized by higher contents in Fe, Ti, Na, Mg, S, Cr, Cu, Ni, V, Zn; and (iii) the south passage between Kimolos and Sifnos, which exhibits higher Ca, S, and Sr contents. Manganese enrichment was observed in and around the bathymetric depression, where Mn oxides act efficiently as scavengers of a suite of metals
Subscription management and charging for value added services in UMTS networks
In this papers we propose a novel architecture for value added services
provision in UMTS networks. The key idea is to introduce a model, which
is capable of handling efficiently subscription management, as well as
charging, billing and accounting for value added services that are
provided either by the network provider or third trusted parties. We
propose a flexible business model inline with the arising requirements
for openness and dynamic subscription and introduce an integrated system
that employs a flexible charging scheme for each type of service usage
(transport and value added), so that the user will receive only one
itemised bill for all services. As a result, the user is able to access
a large number of services provided by independent providers, without
the need for any additional contracts