Supervisors info:
Αριάδνη Αργυράκη Αναπλ. Καθηγήτρια (Επιβλέπουσα), Άνθιμος Ξενίδης Αναπλ. Καθηγητής, Αθανάσιος Γκοντελίτσας Επίκ. Καθηγητής
Summary:
This Thesis presents the results of a lithogeochemical survey conducted in the
Athens Basin, Greece. Forty-six rock samples have been collected and analysed.
The total concentrations of major and trace elements have been used in order to
assess their geochemical associations within the examined rock-types. Moreover,
these concentrations were used to investigate the effect of bedrock composition
on the PHEs enrichment in Athens soil with special emphasis on As which had
been found to be particularly enriched in soil during a previous survey (max
concentration about 200 mg/kg). The examined elements include Si, Al, Mg, Mn,
Ca, Na, Ti, Fe, P, Cr, Ni, K, Rb, Ba, Th, Pb, Nb, P, Sr, As, Sn, Co, Zn, Cu and
Sb. The analyses were conducted using Powder-XRF spectroscopy.
The highest concentrations of arsenic were found in rock samples from the
central and western parts of the Athens Basin. The areas that recorded the
highest average concentrations are Tourkovounia in the north-central part of
the basin and the flanks of Hymettus Mt in the western part of the basin. In
these areas high As is found mainly inside paleosole formations and reach up to
320 mg/kg and in the metamorphosed mica-schists that were highly affected by
weathering phenomena (up to 100 mg/kg). The highest concentrations of Cr and Ni
are found in greenstone of the Hymettus area (396 and 105 mg/kg of Cr and Ni
respectively) and serpetinised ultramafic rocks of Aigaleo (up to 3000 mg/kg
for both elements).
Spider diagrams showed that there is a considerable enrichment in PHEs in the
various rock types of Athens Basin compared to the upper continental crust
concentrations. Also, the Index of Geoacummulation and Enrichment Factor have
been estimated for selected soil-samples collected in a previous top-soil
survey by setting as background values results of the present survey. A
significant output of the present study is its contribution to the availability
of geochemical background data in the Athens Basin concerning total
concentrations of major and trace elements in various rock types. This
information is particularly useful in the assessment of contaminated land as it
provides a basis for comparison against the real geogenic content of the
elements, enables the calculation of realistic elemental enrichment factors in
soil and allows the setting of rational remediation goals in the surface
environment.
Keywords:
Geochemical survey, Athens Basin, Petrology-Geochemistry, bulk chemistry, PHEs
