THE ROLE OF THE HYDROLOGICAL FACTORS IN THE FORMATION OF FIELD CONCENTRATIONS AND FLUXES OF REDUCED GASES, AND MERCURY IN THE SEA OF AZOV

11th International Multidisciplinary Scientific GeoConference SGEM2011, www.sgem.org, SGEM2011 Conference Proceedings/ ISSN 1314-2704, June 20-25, 2011, Vol. 3, 717-722 pp

ABSTRACT

The paper provides an analysis of long-term field studies in the Sea of Azov. The sea is
rich in organic life and is characterized as one of the most bioproductive reservoirs in
the world. During the periods of calm weather the stratification of water mass forms the
fields of hypoxia in some areas of the sea. In the bottom layers of water pockets of
hydrogen sulfide and elevated concentrations of methane and mercury are found.
Mercury coming from both natural and anthropogenic sources is a priority pollutant for
water and sediments. In order to assess the impact on aquatic organisms it’s important
to know not only the content of mercury, but also the predominant forms of its
migration. At the same time these ones are closely related to the salinity and physicochemical
conditions at the interface water – sediments. However, these conditions are
controlled by the dynamics of water masses, suspended matter, as well as the rate of
sedimentation and resuspension of the upper layer of sediments. Long-term field
observations showed a close relationship between the cycles of hydrogen sulfide,
methane, and mercury, on the one hand, and hydrological factors, on the other.

Keywords: Sea of Azov, hydrogen sulfide, mercury, hydrological factors, methane, pH, Eh