NATURAL DEGASSING OF CARBON DIOXIDE AND HYDROGEN SULPHIDE AND ITS ENVIRONMENTAL IMPACT AT MILOS ISLAND, GREECE


Published: Jan 1, 2010
Keywords:
Volcanic gases Health hazard Environmental impact South Aegean Volcanic Arc Milos Island
G.K. Kyriakopoulos
Abstract

The Aegean region represents an active convergent zone, where continental micro-plates exhibit a complex interaction between the African and the Eurasian plates. The calc-alkaline volcanic activity of the Southern Aegean region developed in various volcanic centers from Soussaki to Nisyros through Methana-Poros, Milos and Santorini. Milos Island has been an active volcano till the middle of Quaternary and is at present characterized by a high enthalpy geothermal system. The volcanism started 3.5 Ma ago and still continues up today in the form of post-volcanic manifestations. Most quiescent volcanoes released large amounts of CO2 and H2S through fumarolic activity and soil diffuse degassing. Numerous small fumaroles occur in various places, mainly at Kalamos and Adamas volcanic areas. Also along the southern coast of the island there are volcanic gas manifestations in the sea. Gases were sampled from fumaroles at Kalamos area as well as from north east part of Adamas village. Furthermore many soil gases were sampled at 50 cm depth and analyzed for their chemical composition. Apart from atmospheric gases (N2 and O2), which sometimes contaminate the samples, the main gas phase is CO2. Sometimes also H2S, CH4 and H2 are present in high amounts while CO and He are always present in trace amounts. The He isotopic composition highlights a significant mantle component. CO2 and H2S concentrations higher than in the normal atmosphere can be stimulating for plant growth until certain levels and detrimental above them. As for many active geothermal areas of the world also H2S and CO2 concentrations measured in the area of Milos could be of concern for human health.

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  • Geochemistry and Ore Deposit Geology
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References
Angelier, J., Cantagrel, M., Vilminot, C., 1977. Neotectonique cassante et volcanisme plioquaternaire
dans l’arc eggeen interne: I’lle de Milos (Grece). Bull. Soc. Geol. France, 19, 119-121.
Beauchamp, R.O., Jr, Bus, J.S., Popp, J.A., Boreiko, C.J., Andjelkovich, D.A., 1984. A critical review of
the literature on hydrogen sulfide toxicity. Crit Rev Toxicol 13:25–97.
Chiodini, G., Cioni, R., Leonis, C., Marini, L., Raco, B., 1993. Reactions governing the chemistry of
crater fumaroles from vulcano island Italy, and implications for volcanic surveillance. Appl. Geochem.,
, 357-371.
Delmelle, P. and Stix, J., 2000. Volcanic Gases. In: Encyclopedia of Volcanoes (eds. H. Sigurdsson B.
Houghton S. McNutt H. Rymer J. Stix), Academic Press, San Diego, 803-815.
Dewey, J.F. and Sengor, A.M.C., 1979. Aegean and surrounding regions: complex multiplate and continuum
tectonicsin convergent zone. Bull. Geol. Soc. Am. 90, 84-92.
Dominco, P. and Papastamataki, A. 1975. Characteristics on Greek geothermal waters. 2nd U.N. Symp.
Dev. Use Geoth. Resources. S. Francisco.
Fytikas, M. Giuliani, O. Innocenti, F. Marinelli, G., Mazzuoli, R., 1976. Geochronological data on recent
magmatism of the Aegean Sea. Tectonophysics, 31, T29-T34.
Fytikas, M., Innocenti, F., Kolios, N., Manetti, P., Mazzuoli, R., Poli, G., Rita, F., Villari, L., 1986. Volcanology
and petrology of volcanic products from the island of Milos and neighbouring islets. J. Volcanol.
Geotherm. Res. 28, 297-317.
Fytikas, M., 1989. Updating of the geological and geothermal research on Milos Island. Geothermics, 18,
-496.
Giggenbach,W.F., 1996. Chemical composition of volcanic gases. In: Monitoring and Mitigation of Volcano
Hazards (R. Scarpa, R.I. Tilling, editors) Springer, Berlin, pp. 221-256.
(5) XLIII, No 5 – 2371
Kelepertzis, A. and Kyriakopoulos, K., 1991. Mineralogy and geochemistry of the Mn-mineralization
from Vani area of Milos island-its genesis problem. Prakt. Acad. of Athens, vol. 66, pp. 107-121.
Kyriakopoulos, K., 1998. K-Ar and Rb-Sr isotopic data of white micas from Milos island geothermal
boreholes field. Annal. Geol. Pays Hell. 38, p. 37-48.
Loppi, S., 1996. Lichens as bioindicators of geothermal air pollution in Central Italy. Bryologist 99, 41–48.
Marty, B. and Jambon, A., 1987. C/3He in volatile fluxes from the solid earth: implications for carbon geodynamics
Earth Planet. Sci. Lett, 83,16-26.
Minissale, A., Duchi, V., Kolios, N., Nocenti, M., Verrucchi, C., 1997. Chemical patterns of thermal
aquifers in the volcanic islands of the Aegean arc, Greece. Geothermics, 26, 501-518.
Mitropoulos, P., Tarney, J., Saunders, D., Marsh, N., 1987. Petrogenesis of cenozoic volcanic rocks from
the Aegean Island Arc. J. Volcanol.Geotherm. Res, 32, 177-193.
McKenzie, D., 1972. Active tectonics of the Mediterranean region. Geoph. J. R. Astr. Soc., 30, 55-71.
Mörner, N.A., Etiope, G., 2002. Carbon degassing from the lithosphere, Global Planet. Change 33, 185-
Papadopoulos, B.A., Kondopoulou, D.P., Leventakis, G.A., Pavlides, S.B., 1986. Seismotectonics of the
Aegean Region. Tectonophysics, 124, pp. 67-84.
Papazachos, B.C., 1990. Seismisity of the Aegean and surrounding area. Tectonophysics, 178, 287-308.
Spakman, W., Wortel, M.J.R., Vlaar, N.J., 1988. The Hellenic subduction zone: a tomographic image and
its geodynamic implications. Geophys. Res. Lett. 15, 60-63.
Tretiach, M., Ganis, P., 1999. Hydrogen sulphide and epiphytic lichen vegetation: a case study on Mt.
Amiata (Central Italy). Lichenologist 31, 163–181.
Truffert, C., Chamot-Rooke, N., Lallemant, S., De Voogd, B., Huchon, P., Le Pichon, X., 1992. A crustalscale
cross section of the western Mediterranean ridge from deep seismic data and gravity modelling.
Geophys. J. Int. 114, 360-372.
Witham, C.S., 2005. Volcanic disasters and incidents: A new database. J. Volcanol. Geotherm. Res., 148,
–233.
WHO, 2003. Hydrogen sulphide: human health aspects. Concise International Chemical Assessment
Document 53, World Health Organization, Geneva, pp 26.