Department of Geology and Geoenviromment
Library of the School of Science

2018-03-05

2018

Valla Poulcheria

Αριάδνη Αργυράκη, Αναπληρώτρια Καθηγήτρια Tομέα Οικονομικής Γεωλογίας και Γεωχημείας, Τμήμα Γεωλογίας και Γεωπεριβάλλοντος, Εθνικό και Καποδιστριακό Πανεπιστήμιο Αθηνών

Υδατο-εκχυλίσιμο εξασθενές χρώμιο σε πυρωμένα σερπεντινικά εδάφη

Greek

Water-leachable hexavalent chromium in calcined serpentine soils

The enrichment of soils overlying ophiolithic complexes in hexavalent chromium after fires has already been identified in previous studies. Chromium is contained in the minerals (mainly chromite) of the ophiolithic rocks, such as peridotite and dunite. This paper presents the results of laboratory experiments carried out on soil samples of the area of Grevena in order to examine and measure the presence of hexavalent chromium (CrVI) in extracts of soils, especially serpentine soils, which have been burned.
The study of hexavalent chromium (CrVI) concentrations in the soil sample extracts of three different geological backgrounds (carbonate rocks, molassic sediments, serpentinated ultramafic rocks) was performed by firing the samples at 600 °C for 1 hour, then preparing solutions (6g of soil / 120 mL of deionized water) with both the raw and the calcined samples, which after being shaken for 5 minutes, were leached under vacuum. Finally, pH, TDS and CrVI concentrations tests were carried out to the resulting extracts. Mineralogical analysis by X-ray diffraction (XRD) and SEM analysis has been conducted on selected soil samples before and after the firing process.
The highest CrVI concentrations are observed in soils with serpentinated ultramafic background in both the burned (mean 1110 μg/L) and raw samples (mean 20 μg/L). The firing time appears to affect chromium concentrations, while the shaking time is not. The pH levels increase after the firing process on all samples, creating alkaline conditions (pH ≥7-9) favoring the stabilization of hexavalent chromium. The hexavalent chromium leached from the calcined samples from all three categories of geological background exceeds the permitted concentration of hexavalent chromium in drinking water (50 μg/L), and might pose an additional environmental hazard in case agricultural and terrestrial areas were burned.

Science

Ophiolites, Calcination, Leaching, Hexavalent chromium (CrVI)

Yes

3

Yes

33

109

File access is restricted only to the intranet of UoA.

https://pergamos.lib.uoa.gr/uoa/dl/object/2680908