West Balkan Region Research Articles

Analysis of Air Quality Observations with the Aid of the Source-Receptor Relationship Approach

In this study, an attempt was made to analyze time series of air quality measurements (O3, SO2, SO4 2−NOx) conducted at a remote place in the eastern Mediterranean (Finokalia at Crete Island in 1999) to obtain concrete information on potential contributions from emission sources. For the definition of a source-receptor relationship, advanced meteorological and dispersion models appropriate to identify “areas of influence” have been used. The model tools used are the Regional Atmospheric Modeling System and the Lagrangian-type particle dispersion model (forward and backward in time), with capabilities to derive influence functions and definition of “areas of influence.” When high levels of pollutants have been measured at the remote location of Finokalia, particles are released from this location (receptor) and traced backward in time. The influence function derived from particle distributions characterizes dispersion conditions in the atmosphere and also provides information on potential contributions from emission sources within the modeling domain to this high concentration. As was shown in the simulation results, the experimental site of Finokalia in Crete is influenced during the selected case studies, primarily by pollutants emitted from the urban conglomerate of Athens. Secondarily, it is influenced by polluted air masses arriving from Italy and/or the Black Sea Region. For some specific cases, air pollutants monitored at Finokalia were possibly related to war activities in the West Balkan Region (Kosovo).

Distribution of the silver in Bulgaria ore deposits

The content of silver in the different, in terms of genesis and macrochemism, endogenic mineralisations in Bulgaria varies from 1-2 to 200 g/t, most frequently 5-35 g/t. The highest concentrations of this element are registered in the West Balkan region (lead-silver ores near Chiprovtsi, gold-sulphide ores near Govezhda and polymetallic ores Iskar-Vratsa ore region as well as Kremikovtsi deposit); in the Central Rhodopes region (lead-zinc deposits in Laki, Madan and Davidkovo ore fields, Ardino silver-polymetallic deposit); in the lead-zinc ores in Ossogovo ore region; in the East Rhodopes ore region (gold-silver-polymetallic ores in Madzharovo ore field and Popsko, silver-gold ores in Sedefche and Sarnak); in the East Srednogorie (gold-copper-polymetallic ores near Bakadzhik and Zidarovo). Some of the more significant favourable geological prerequisites for the accumulation of silver in the ores are: Late Paleozoic or Tertiary (Oligocene-Miocene) age, geodynamic environments of collision and zones with thick earth crust, anticlinoria and big horst-like uplifts, WNW and NW host structures, close to the surface or flange sections of the mineralisations. The mineralisations with higher content of silver are, as a rule, related to granites. Their host rocks are carbonates with development of metasomatic processes such as dolomitisation and granitoids with periore alterations of the quartz-sericite, quartz-mica (beresite), adular-sericite or quartz-adularia metasomatites and argillizites. The composition of the ores includes lithophile-chalcophile geochemical associations with prevalence of antimony. A favourable factor for the accumulation of silver is the lead-zinc macrochemism with prevalence of lead in zones with thick earth crust and the polymetallic - in zones with basificated (subocean type) earth crust. The mineral composition of the ores includes galena, sulphosalt silver minerals, the especially high silver-bearing tetrahedrite-tennantite series with prevalence of tetrahedrite and participation of magnesium and iron carbonates (siderite, ankerite, dolomite). The character of the silver-bearing mineralisations in Bulgaria is medium to low-temperature and, according to their peculiarities, they can be related to the mesothermal, epithermal or telethermal genetic classes.