Mineral, chemical and radiological investigation of a black sand at Touzla Cape, near Thessaloniki, Greece

A black-sand formation located at Touzla Cape, near Thessaloniki city, Greece, was investigated using optical microscopy, powder-XRD, SEM-EDS, INAA and in-situ -ray spectrometry. This black sand is mainly composed of ilmenite, magnetite, garnet, zircon and rutile. Also present, in minor or trace amounts, are quartz, sphene, pyroxenes, sillimanite, feldspars, biotite, haematite, tourmaline, chromite, niobian-rutile and pyrrhotite. Niobian-rutile and pyrrhotite were found as inclusions in ilmenite and magnetite respectively. The radioactivity measurements indicated contributions of the uranium and thorium radioactive series and of 40K and 137Cs, and the maximum value of the total absorbed dose rate in air was found to be 62, 172, 8 and 2 nGy h-1 respectively. The main radioactivity of the uranium and thorium series is attributed to the fractions of zircon (304 µg Th g-1 and 157 µg U g-1), of ilmenite (89 µg Th g-1) and to a lesser extent to the fraction of garnet (5 µg Th g-1). The zircon fraction also contained 5076 µg Hf g-1. Some minerals and elements (Ti, Zr, Hf, Th, U) contained in the black sand could be of potential economic value. The high proportions of monomineralic grains along with the variations observed in mineral phases, in colour, in sphericity, in roundness, in grain size, in composition and in mineral inclusions, imply that the minerals and grains were subjected to several cycles of weathering and sedimentation, as well as being derived from multiple source rocks and areas.     

Unregulated urban sprawl and spatial distribution of fire events: evidence from Greece

Fire events are an annual phenomenon in Greece with damages and even casualties, making their understanding and management important. In this paper, we present fire events provided by NASA Fire Information for Resource Management System and place them along a number of spatial types defined by relief and land cover classes. Results demonstrate that the occurrence of fire events is related more to some land cover classes than others. The most important in terms of overall frequency in all types of terrain is ‘Agricultural Areas’, as a result of farming practices that involve fire. The second more important type of areas is ‘Artificial Surfaces’, especially in low lying areas. These events are related to urban growth and sprawl and are very often a direct outcome of speculation practices with land properties, encouraged by the absence or poor implementation of spatial planning.     

Behavior study of trace elements in pulverized lignite, bottom ash, and fly ash of Amyntaio power station, Greece

The Kozani–Ptolemais–Amyntaio basin constitutes the principal coal field of Greece. Approximately 50 % of the total power production of Greece is generated by five power stations operating in the area. Lignite samples, together with the corresponding fly ash and bottom ash were collected, over a period of 3 months, from the power plant of Amyntaio and analyzed for their content in 16 trace elements. The results indicate that Y, Nb, U, Rb, Zr, Ni, Pb, Ba, Zn, Sr, Cu, and Th demonstrate an organic affinity during the combustion of lignite, while V has an inorganic affinity. Three elements (Co, Cr, and Sc) show an intermediate affinity.     

Extra-framework cation release from heulandite-type rich tuffs on exchange with NH(4)(+)

The outgoing cations of Greek heulandite-rich tuff samples (heulandite type-III, 91wt.%, mica 4wt.%, feldspar 5wt. %, CEC 2.22meq/g) were analysed upon exchange with ammonium acetate using atomic absorption spectrometry (AAS). The kinetic curves of each cation were investigated over a total time of contact of 720h with sampling at frequent intervals. The materials were examined by powder X-ray diffraction, SEM-EDS, and AAS. The sorption ability was measured using the ammonium acetate saturation method. It was found that Ca(2+) presents an unexpected extra-framework release and a surprisingly high degree of exchange (90%). The exchange of Mg (57%) is also worthy of note whereas the behavior of K(+) showed an expected rapid initial release. The behavior of Na(+) must be similar. However, its lower concentration in the zeolitic material minimizes its overall significance somewhat. On the other hand, Ca(2+) and Mg(2+) release is kinetically much slower, compared to that of alkali metal ions, and this phenomenon indicates that different exchange energies are needed till final equilibrium.     

Investigation of the uptake ability of fly ashes produced after lignite combustion

Fly ash samples from the five steam electric power stations of the Lignite Center of Western Macedonia were used in this study. They consisted mainly of anhydrite, lime, quartz and amorphous material as well as feldspars, calcite, micas + clays, portlandite and gehlenite which were all present in minor amounts. Anhydrite, lime and portlandite in the fly ash samples diminished upon treatment with ammonium acetate aqueous solution, whereas quartz, feldspars, gehlenite and amorphous material were enriched. The uptake ability of the fly ash samples ranged from 89 to 101 mequ./100g. The uptake ability of the samples was mainly attributed to the amorphous material and the microporous minerals, micas + clays. The amorphous material content was estimated at between 17 and 20 wt% in the treated fly ashes and may be unburned organic matter and amorphous inorganic material that resulted during the combustion of the lignite. A positive correlation was observed between the uptake ability and the total percentage of amorphous material and micas + clays. The relatively high uptake ability of the fly ash samples could lead to additional industrial and environmental uses of the fly ashes. The environmental advantage of fly ash exploitation will be particularly important for large electric power centers, such as the LCWM.     

Coastal landscape and the Greek spatial planning: evidence from windpower in the South Aegean islands

This paper discusses issues about the coastal and the insular landscape integration in the Greek spatial planning framework. Case study area is the region of the South Aegean, where the proliferation of wind turbines is one of the principal factors of landscape change. The methodological approach adopted is mainly quantitative and is based on viewshed analysis. This paper is also demonstrates that zones with varying impact on landscape can be identified. It also emerges that the spatial planning framework in Greece promotes an ad hoc project-led instead of a plan-based approach to coastal and insular landscape management.     

Major and trace element contents in apples from a cultivated area of central Greece

Forty-two soil and apple samples from central Greece were collected and analyzed with regards to the content in major (Ca, Fe, K, Mg, Na, P, and S) and trace elements (As, B, Ba, Cd, Co, Cr, Cu, Hg, Mn, Mo, Ni, Pb, Sb, Sc, Se, Sr, Ti, and Zn). Soil samples were analyzed by inductively coupled plasma atomic emission spectrometry, while for the apples inductively coupled plasma mass spectrometry was implemented. Several elements such as As, B, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Se, Ti, and Zn, represent high concentrations in apples from the study area. These relatively high concentrations may be a consequence of the local geology, along with the excessive application of agricultural products such as fertilizers and agrochemicals.