MINERALOGICAL AND GEOCHEMICAL CHARACTERIZATION OF THE OLYMPIAS MINE TAILINGS, NE CHALKIDIKI, GREECE

Τα τέλματα της Ολυμπιάδας στην ΒΑ Χαλκιδική, αποτελούν τα κατάλοιπα του εμπλουτισμού του κοιτάσματος Pb-Zn-Au-Ag που εντοπίζεται στα ανθρακικά πετρώματα της Ενότητας Κερδυλίων. Στην παρούσα εργασία, η ορυκτολογική σύσταση των τελμάτων προσδιορίστηκε με τη χρήση περιθλασιμετρίας ακτίνων-Χ (XRD), ηλεκτρονικής μικροσκοπίας σάρωσης (SEM) και οπτικής μικροσκοπίας, ενώ επιπλέον πραγματοποιήθηκαν χημικές αναλύσεις και μετρήσεις pH. Τα αποτελέσματα έδειξαν πως τα τέλματα συνίστανται από σύνδρομα ορυκτά (χαλαζίας, ροδοχρωσίτης, ασβεστίτης, άστριοι, μαρμαρυγίες, καολινίτης και ακτινόλιθος) και σουλφίδια (σιδηροπυρίτης, αρσενοπυρίτης, σφαλερίτης, χαλκοπυρίτης και γαληνίτης), κάτι που δείχνει ότι υπάρχει σχέση με την ορυκτολογική σύσταση της μεταλλοφορίας και των 2089 μητρικών πετρωμάτων. Επίσης, τα τέλματα αποτελούνται από ίχνη οξειδίων Fe (μαγνητίτης, αιματίτης), οξείδια-υδροξείδια Fe (γκαιτίτης) και οξείδια Mn, συχνά εμπλουτισμένα σε Zn και Pb και σε ορισμένες περιπτώσεις Fe, Sb και As. Επιπλέον εντοπίστηκαν δευτερογενή θειικά άλατα (γύψος, ιαροσίτης) και επανθίσματα θειικών αλάτων (σιδηροεξαϋδρίτης, εξαϋδρίτης, αλοτριχίτης). Τα τέλματα της Ολυμπιάδας είναι γενικά μη οξειδωμένα, δημιουργώντας ένα αλκαλικό περιβάλλον. Παρόλα αυτά, λόγω μεταβολών στη σύσταση, σχηματίζονται ξεχωριστές φάσεις περιορισμένης έκτασης, όπως λεπτές στρώσεις και φακοί οξειδωμένου υλικού, οι οποίες δημιουργούν όξινο περιβάλλον. Από την άποψη της περιεκτικότητας σε πολύτιμα μέταλλα, τα τέλματα της Ολυμπιάδας είναι εμπλουτισμένα σε Au (έως 12 g/t) και Ag (έως 20 g/t).The Olympias tailings of NE Chalkidiki, Greece represent the mine wastes produced by the beneficiation of the Pb-Zn-Au-Ag ore deposit, which is hosted within the carbonate rocks of the Kerdylia Unit. In the present study X-Ray diffraction (XRD), scanning electron microscopy (SEM), optical microscopy, chemical analyses and pH measurements were conducted to determine the tailings mineralogy and chemical composition. The results indicated that they consist of gangue (quartz, rhodochrosite, calcite, dolomite, feldspars, micas, kaolinite and actinolite) and sulfide minerals (pyrite, arsenopyrite, sphalerite, chalcopyrite and galena), reflecting the source ore and its host rock composition, accompanied by traces of Fe-oxides (magnetite, hematite), Fe oxyhydroxides (goethite) and Mn-oxides, often enriched in Zn and Pb and in some cases Fe, Sb and As. Secondary sulfates (gypsum, jarosite) and surface efflorescent salts (ferrohexahydrite, hexahydrite, halotrichite) have also been recognized. The Olympias tailings are generally unoxidized, generating an alkaline environment. However, variations in composition result in the formation of restricted separate phases, such as thin layers and lenses of oxidized material that generates an acidic environment. In terms of precious metals content, the Olympias tailings are enriched in Au (up to 12 g/t) and Ag (up to 20 g/t)

Development of methods for the determination of metal ions and their species interlaced with biomolecules by atomic spectrometry techniques and use of chemimetric methods for the optimization

The aim of the present dissertation study was to develop and optimize analytical methods for the analysis of eight different metals: Cd, Co, Cr, Cu, Mn, Ni, Pb and Hg in the human blood and its fractions as well as the elements Hg and methylmercury in human urine and natural water reserves (drinking water and sea water). Since the concentrations for most of the above mentioned metals are especially low, two different spectroscopic techniques were used in order to minimize the time of analysis and to achieve the best possible accuracy in the measurements. Inductively coupled plasma atomic emission spectrometry (ICP- AES) was used as a multi-element analytical technique and the electrothermal atomic absorption technique (ET-AAS) was used complementarily for very low concentrations. Finally, only in the case of mercury and methylmercury a novel nonchromatographic on-line cold vapour atomic absorption spectrometric method (CV-AAS) was utilized for analysis. In the beginning an analytical method was developed using inductively coupled plasma atomic emission spectrometry (ICP-AES) for the direct determination of seven elements (Cd, Co, Cr, Cu, Mn, Ni and Pb) in the fractions of human blood: plasma, cytoplasm and whole blood. The optimum wavelength for each metal was chosen according to several criteria such as sensitivity, linearity and the estimated recovery of the standard aqueous solution. The procedure of pretreatment of each sample was also studied such as the centrifugal conditions, the necessity of utilizing digestion procedures for the sample and the necessary dilution of the digests. For the plasma sample it was possible to avoid utilizing digestion procedures, but for the cytoplasm and the whole blood such a procedure was unavoidable. The samples were acid digested with HNO3 in closed tubes made of PTFE under high temperature and pressure conditions and then they were diluted before their injection in the ICP-AES. In addition, the optimization of inductively coupled plasma conditions was performed such as the Argo flow rate, the sample flow rate and the power of the radiofrequency for each of the samples. Finally, the impact of the calibration technique on the total variation of the method was examined. The standard addition technique was found to be the most accurate for the determination of the metals, as far as the retention of the metals was concerned. The recovery for all the samples examined with this particular method was satisfactory (Cd 99 %, Co 101 %, Cr 100 %, Cu 99 %, Mn 101 %, Ni 100 %, and Pb 97 %). Based on the analytical characteristics of the previously mentioned method, the detection limits which were achieved and the control of the accuracy of the method was examined using Seronorm trace elements whole blood L-3. It is recommended that this method could be used to monitoring people who have been exposed to high concentrations of those metals. Especially for the quantitative determination of copper, which usually is present at high concentrations, it is possible to implement this method directly even in cases of samples taken from people that have not been exposed.Στα πλαίσια της παρούσας διδακτορικής διατριβής αναπτύχθηκαν και βελτιστοποιήθηκαν αναλυτικές μέθοδοι για την ανάλυση οχτώ μετάλλων, Cd, Co, Cr, Cu, Mn, Ni, Pb και Hg σε ολικό ανθρώπινο αίμα και κλάσματά του, καθώς επίσης και Hg και μεθυλ-υδραργύρου σε ανθρώπινα ούρα και φυσικά ύδατα. Γνωρίζοντας ότι για τα περισσότερα από τα μελετούμενα μέταλλα οι συγκεντρώσεις είναι ιδιαίτερα χαμηλές στα προαναφερθέντα δείγματα χρησιμοποιήθηκαν δύο φασματομετρικές τεχνικές προκειμένου να μειωθεί ο χρόνος ανάλυσης και να επιτευχθεί η μέγιστη ακρίβεια στην ποσοτική αποτίμηση των αποτελεσμάτων. Έτσι αρχικά χρησιμοποιήθηκε η φασματομετρία ατομικής εκπομπής επαγωγικά συζευγμένου πλάσματος (ICP-AES) ως πολυστοιχειακή τεχνική ανάλυσης και η ατομική απορρόφηση ηλεκτροθερμικού φούρνου γραφίτη (ET-AAS) ως πιο ευαίσθητη τεχνική ανάλυσης συγκριτικά με την προηγούμενη. Τέλος για την περίπτωση και μόνο του υδραργύρου και του μεθυλ-υδραργύρου χρησιμοποιήθηκε η ατομική απορρόφηση ψυχρού ατμού (CV-AAS). Σε πρώτη φάση αναπτύχθηκε αναλυτική μέθοδος που χρησιμοποιεί την φασματομετρία ατομικής εκπομπής με επαγωγικά συζευγμένο πλάσμα (ICP-AES) για γρήγορο και ταυτόχρονο προσδιορισμό επτά βαρέων μετάλλων (Cd, Co, Cr, Cu, Mn, Ni και Pb) στα κλάσματα του ανθρώπινου αίματος, όπως το πλάσμα, το κυτταρικό κλάσμα του αίματος και το ολικό αίμα.Το βέλτιστο μήκος κύματος για κάθε μέταλλο επιλέχτηκε χρησιμοποιώντας ως κριτήριο την ευαισθησία, τη γραμμικότητα και την υπολογιζόμενη ανάκτηση των υδατικών προτύπων διαλυμάτων. Μελετήθηκε η διαδικασία προκατεργασίας του κάθε δείγματος, οι συνθήκες φυγοκέντρησης, η αναγκαιότητα υποβολής του δείγματος σε πέψη και η απαιτούμενη αραίωση των δειγμάτων. Για τα δείγματα πλάσματος ήταν δυνατό να αποφευχθεί η διαδικασία της πέψης του δείγματος, αλλά για το κυτταρικό κλάσμα και το ολικό αίμα η πέψη είναι απαραίτητη. Τα δείγματα υποβλήθηκαν σε όξινη πέψη με HNO3 σε κλειστά δοχεία από PTFE, υπό συνθήκες υψηλής θερμοκρασίας και πίεσης και αραιώθηκαν πριν από την εισαγωγή στο ICP-AES. Επίσης, πραγματοποιήθηκε βελτιστοποίηση των συνθηκών λειτουργίας του φασματομέτρου ατομικής εκπομπής με επαγωγικά συζευγμένο πλάσμα, όπως η ροή αργού στον εκνεφωτή, η παροχή εισαγωγής του δείγματος και η ισχύς της γεννήτριας ραδιοσυχνοτήτων για κάθε είδος δείγματος. Τέλος, εξετάστηκε η επίδραση της τεχνικής χάραξης της καμπύλης αναφοράς στην ολική διακύμανση της μεθόδου. Η τεχνική της προσθήκης προτύπου αποδείχθηκε ακριβέστερη για τον προσδιορισμό των μετάλλων από την άποψη της ανάκτησής τους στα δείγματα. Για το σύνολο των εξεταζομένων κλασμάτων παρουσιάζονται η ευαισθησία και η ανάκτηση(Cd 99 %, Co 101 %, Cr 100 %, Cu 99 %, Mn 101 %, Ni 100 % και Pb 97 %) για τη συγκεκριμένη μέθοδο που αναπτύχθηκε. Με βάση τα καλά αναλυτικά χαρακτηριστικά της μεθόδου, τα όρια ανίχνευσης που επιτεύχθηκαν και τον έλεγχο της ακρίβειας της μεθόδου με το πρότυπο υλικό αναφοράς ολικού αίματος ιχνοστοιχείων, επιπέδου 3 του οίκου Seronorm (Seronorm trace elements whole blood L-3) προτείνεται η εφαρμογή της μεθόδου για άτομα, τα οποία έχουν εκτεθεί σε υψηλές συγκεντρώσεις των μελετούμενων μετάλλων και γενικότερα για τη γρήγορη παρακολούθηση (monitoring) των επιπέδων των επτά αυτών στοιχείων. Ιδιαίτερα για τον ποσοτικό προσδιορισμό του χαλκού, ο οποίος εμφανίζει υπό φυσιολογικές τιμές υψηλές συγκεντρώσεις είναι δυνατή η άμεση εφαρμογή της μεθόδου ακόμη και σε περιπτώσεις δειγμάτων, όπου δεν υφίσταται κάποια επιπλέον επιβάρυνση

Geochemical signature of surface water and stream sediments of a mineralized drainage basin at NE Chalkidiki, Greece: A pre-mining survey

The geochemical characteristics of surface water and stream sediments in Asprolakkas drainage basin, an area of Tertiary mineralization within amphibolite, located at NE Chalkidiki peninsula, Greece, were investigated in order to establish the geochemical baseline conditions prior to any type of new mining activities. The area represents the only example of active mining and processing of base metal sulfide ore in Greece and also includes an unmined porphyry Cu-Au ore deposit at Skouries. In a wider context, this research represents a pre-mining baseline geochemical study that can be used as an analog for similar metallogenetic provinces in areas with a Mediterranean type climate. Concentrations of dissolved major ions and trace metals displayed wide variability within the study area. Kokkinolakkas stream, draining the exploited Pb-Zn (±Ag) ore bodies, is strongly influenced by chemical weathering of sulfide minerals and presents elevated levels of SO 4 (429-857mgl -1), Pb (4-64μgl -1), Zn (290-1350μgl -1), Mn (1680-7899μgl -1), Ni (12-50μgl -1), Cd (2-8μgl -1), As (8-45μgl -1) and Sb (9-16μgl -1). Stream water of unmined areas demonstrated a different chemical composition with elevated values mainly for Pb (up to 45μgl -1) and As (up to 141μgl -1). Hydrological conditions highly influence the behavior of major elements and metals. Stream bed sediments from Kokkinolakkas and Tsarkia Lakkos, located at the head waters of Asprolakkas basin, have anomalous values in Pb (1165-3439mgkg -1), Zn (1368-4538mgkg -1), As (964-2714mgkg -1), Sb (30-70mgkg -1), Cd (3.8-21.6mgkg -1) and Mn (6811 up to >10,000mgkg -1). Mobility of selected trace metals was investigated through the application of a 5-step sequential extraction procedure. Results show that, despite the high total metal content, the majority of analyzed elements are mainly bound to relatively immobile operationally defined geochemical phases of amorphous to poorly crystalline Fe and Mn oxides and the residual fraction. Considering the planned mining developments in the area, the results of this study may assist mine planners to set realistic goals for monitoring and remediation programs. © 2012 Elsevier B.V

Distribution and accumulation of metals in tadpoles inhabiting the metalliferous streams of eastern chalkidiki, northeast Greece

The present study investigates the accumulation of heavy metals [copper (Cu), lead (Pb), zinc (Zn), magnesium (Mn), cadmium (Cd), nickel (Ni), and chromium (Cr)] in tadpoles inhabiting the metalliferous streams flowing within the Asprolakkas River basin (northeast Chalkidiki peninsula, Greece) and the effect of potentially harmful elements in stream water and sediment on the corresponding levels in their tissue. Animals were collected from six sampling sites influenced by a wide range of surface water and stream sediment trace element concentrations. The results of the chemical analyses showed that tadpoles accumulated significant levels of all of the examined metals. The range of whole-body mean measured concentrations were (in dry mass) as follows: Cu (46-182 mg/kg), Pb (103-4,490 mg/ kg), Zn (494-11,460 mg/kg), Mn (1,620-13,310 mg/kg), Cd (1.2-82 mg/kg), Ni (57-163 mg/kg), and Cr (38- 272 mg/kg). The mean concentrations of Pb, Zn, Mn, Ni, Cr, and Cd in Kokkinolakkas stream, which drains a currently active mining area, were the highest ever reported in tadpoles. Our results indicate that whole-body levels of Pb, Zn, Cu, and Cd increase with stream sediment concentrations and that these organisms tend to accumulate metals bound to Fe and Mn oxides. In addition, high dissolved concentrations and significant concentrations associated with more labile geochemical phases of sediments for specific metals were contributing factors determining whole-body levels. Given the observed bioconcentration factors, as well as the correlation with sediment concentrations, it is proposed that these organisms could be considered as bioindicators of environmental contamination and may be used for monitoring purposes within this metal-rich zone and, perhaps, within other rivers affected by metal mining. © Springer Science+Business Media, LLC 2012

Investigation of Trace and Critical Elements (Including Actinides) in Flotation Sulphide Concentrates of Kassandra Mines (Chalkidiki, Greece)

Pyrite/arsenopyrite (Py-AsPy), galena (PbS), and sphalerite (ZnS) concentrates from the flotation plants of Olympias and Stratoni (Kassandra mines, Chalkidiki, N. Greece) were investigated for their major, trace, minor, and critical element contents, including actinides associated to natural radioactivity. It is revealed that in addition to the Pb, Zn, Ag, and Au being exploited by Hellas Gold S.A., there are also significant concentrations of Sb and Ga (Sb: >0.2 wt.% in PbS concentrate; Ga:25 ppm in ZnS concentrate), but no considerable contents of Bi, Co, V, or REE. Concerning other elements, As was found in elevated concentrations (>1 wt.% in Py-(As)Py-AsPy Olympias concentrate and almost 1 wt.% in Stratoni PbS and ZnS concentrates) together with Cd (specifically in ZnS concentrate). However, actinides occurred in very low concentrations (U < 2 ppm and Th < 0.5 ppm in all examined concentrates), limiting the possibility of natural radioactivity in the Hellas Gold S.A. products. The concentrations of the natural radionuclides (238U, 232Th, and 40K) are much lower than those of commercial granitic rocks, and thus the associated radioactive dose is insignificant

Investigation of trace and critical elements (Including actinides) in flotation sulphide concentrates of Kassandra mines (chalkidiki, Greece)

Pyrite/arsenopyrite (Py-AsPy), galena (PbS), and sphalerite (ZnS) concentrates from the flotation plants of Olympias and Stratoni (Kassandra mines, Chalkidiki, N. Greece) were investigated for their major, trace, minor, and critical element contents, including actinides associated to natural radioactivity. It is revealed that in addition to the Pb, Zn, Ag, and Au being exploited by Hellas Gold S.A., there are also significant concentrations of Sb and Ga (Sb: >0.2 wt.% in PbS concentrate; Ga:25 ppm in ZnS concentrate), but no considerable contents of Bi, Co, V, or REE. Concerning other elements, As was found in elevated concentrations (>1 wt.% in Py-(As)Py-AsPy Olympias concentrate and almost 1 wt.% in Stratoni PbS and ZnS concentrates) together with Cd (specifically in ZnS concentrate). However, actinides occurred in very low concentrations (U < 2 ppm and Th < 0.5 ppm in all examined concentrates), limiting the possibility of natural radioactivity in the Hellas Gold S.A. products. The concentrations of the natural radionuclides (238U, 232Th, and 40K) are much lower than those of commercial granitic rocks, and thus the associated radioactive dose is insignificant. © 2019 by the authors. Licensee MDPI, Basel, Switzerland

Mineral chemistry of sulphide minerals in concentrates of the Kassandra mines (Chalkidiki, Greece)

The Kassandra mining district contains porphyry Au-Cu and Au-Ag-Pb-Zn-Cu carbonate replacement deposits that are associated with Oligocene-Miocene intrusions emplaced into polydeformed metamorphic basement rocks belonging to the Permo-Carboniferous to Late Jurassic Kerdilion unit and the Ordovician-Silurian Vertiskos unit. Regional extensional tectonics active since the middle Eocene resulted in the development of widespread normal and transtensional faults, including the Stratoni fault zone that hosts carbonate replacement sulfide ore bodies (Siron et al., 2018). More particularly, Stratoni (Madem Lakkos, Mavres Petres) and Olympias are the two main carbonate-replacement massive sulphide Pb-Zn (Ag-Au) deposits of the district; they are located on the footwall of the Tertiary Stratoni-Varvara fault. Both deposits are interpreted to form the proximal and distal part of a fault-controlled exoskarn-type ore system triggered by nearby small-scale intrusions close to the fault system (Hahn et al., 2012). The mineral chemistry of basic sulfide minerals (major phases) into concentrates from the flotation plants of Stratoni and Olympias mines was investigated by EPMA using a JEOL 8200 SEM equipped with WDS. The chemical formulae of the minerals in their relevant concentrates were calculated as following: Galena (Stratoni Mine): Pb0.975-0.990Zn0.000-0.004Mn0.000-0.002As0.000-0.001S Sphalerite (Stratoni Mine): Zn0.788-0.845Fe0.118-0.167Mn0.006-0.010Pb0.000-0.001S Pyrite (Olympias Mine): Fe1.019-1.051As0.000-0.033Pb0.000-0.001Zn0.000-0.001S2 Arsenopyrite (Olympias Mine): FeAs0.848-0.878S1.065-1.131 In addition, the presence of boulangerite was detected in the pyrite/arsenopyrite concentrate, with microprobe analyses revealing the following chemical formula: Pb5.182-5.253Sb4.214-4.449As0.058-0.154Fe0.040-0.154Zn0.000-0.063Mn0.010-0.020S11 All sulphide minerals studied were found having typical/expected chemical compositions in major elements. Ongoing research on these samples is also targeting the determination of their trace element concentrations, focusing on noble metals (Godelitsas et al., 2015; Kasama et al., 2018) and elements considered as Critical Raw Materials (CRM) for the EU. Aknowledgments. This research is implemented through IKY scholarships programme and co-financed by the European Union (European Social Fund - ESF) and Greek national funds through the action entitled \u201dReinforcement of Postdoctoral Researchers\u201d, in the framework of the Operational Programme \u201dHuman Resources Development Program, Education and Lifelong Learning\u201d of the National Strategic Reference Framework (NSRF) 2014 \u2013 2020

Colloidal gold nanoparticle probe-based immunochromatographic assay for the rapid detection of chromium ions in water and serum samples

An immunochromatographic assay (ICA) using gold nanoparticles coated with monoclonal antibody (McAb) for the detection of chromium ions (Cr) in water and serum samples was developed, optimized and validated. Gold nanoparticles coated with affinity-purified monoclonal antibodies against isothiocyanobenzyl-EDTA (iEDTA)-chelated Cr(3+) were used as the detecting reagent in this completive immunoassay-based one-step test strip. The ICA was investigated to measure chromium speciation (Cr(3+) and Cr(6+) ions) in water samples. Chromium standard samples of 0-80 ng/mL in water were determined by the test strips. The results showed that the visual lowest detection limit (LDL) of the test strip was 50.0 ng/mL. A portable colorimetric lateral flow reader was used for the quantification of Cr. The results indicated that the linear range of the ICA with colorimetric detection was 5-80 ng/mL. The ICA was also validated for the detection of chromium ions in serum samples. The test trips showed high stability in that they could be stored at 37°C for at least 12 weeks without significant loss of activity. The test strip also showed good selectivity for Cr detection with negligible interference from other heavy metals. Because of its low cost and short testing time (within 5 min), the test strip is especially suitable for on-site large-scale screening of Cr-polluted water samples, biomonitoring of Cr exposure, and many other field applications