The objective of this study was to assess the bulk chemical composition as well as the extent and severity of heavy metal contamination in the paddy soil of Kočani Field (eastern Macedonia). The results revealed that the paddy soil of the western part of Kočani Field is severely contaminated with Pb, Zn, As and Cd in the vicinity of the Zletovska River due to irrigation with riverine water that is severely affected by acid mine and tailing effluents from the Pb-Zn mine in Zletovo. The detected total concentrations of these metals are far above the threshold values considered to be phytotoxically excessive for surface soil. The paddy soil in the vicinity of the Zletovska River was also found to exhibit elevated levels of Ba, Th, U, V, W, Mo, Cu, Sb, Bi, Ag, Au, Hg and Tl, with concentrations above their generally accepted median concentration values obtained during this study. A correlation matrix revealed that the Mn and Fe oxides/ hydroxides are the most important carrier phase for several trace elements, with the exception of rare earth elements (REEs). These also represent a major sink for the observed heavy metal pollution of thesoil. REEs are mostly associated with two phases: light (L)REEs are bound to K-Al, while heavy (H)REEs are bound to Mg-bearing minerals. Although there is no direct evidence of a health risk, the paddy soil in the vicinity of Zletovska River needs further investigation and an assessment should be made of its suitability for agricultural use, particularly in view of the highly elevated concentrations of Pb, Zn, As and Cd.

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The internal oxidation of a two-phase at.% Se alloy in pure oxygen was studied at 750, 800 and 830 • C. The alloy is composed of a dilute solid solution of selenium in silver) and Ag 2 Se intermetallic particles. The internal oxidation of this alloy proceeds through gradual in-situ oxidation of the Ag 2 Se particles as well as through diffusive internal oxidation of selenium from solid solution. Gradual in-situ internal oxidation of Ag 2 Se particles reflects itself in the appearance of two internal-oxidation fronts, inner and outer, marking the beginning and end of the in-situ oxidation of Ag 2 Se particles. The oxide phase formed during in-situ oxidation is the molten double oxide, Ag 2 SeO 3 . A theoretical treatment of the phase relationships in a hypothetical Ag-Ag 2 Se-Ag 2 SeO 3 ternary phase diagram is presented to assist the explanation of the mechanism of in-situ oxidation. The kinetics of oxidation are presented in Part II.KEY WORDS: silver-selenium alloy; Ag 2 Se in-situ oxidation; Ag 2 SeO 3 ; internal oxidation of two-phase alloys.

The northern Karavanke Granitic Massif straddles the Slovenian-Austrian border. The investigated area lies in northern Slovenia, and extends from the western Slovenian-Austrian border to the east for about 30 km, with a maximum width of 2 km. The massif exhibits a bimodal magmatic association comprising mainly syenogranite and syenite with contemporaneous gabbroic rocks. Rocks of intermediate composition are less abundant and show field, textural and chemical features suggesting that they have formed as a result of the interaction (mixing and mingling) between felsic and mafic magmas. Plagioclasemantled alkali feldspars occur in dikes of porphyritic syenite, which cut larger bodies of gabbroic rocks. Field, mineralogical, petrographic and geochemical evidences suggest that the porphyritic syenite is a hybrid rock, formed by the interaction of mafic and felsic magmas. The formation of plagioclase-mantled alkali feldspar can be explained by the introduction of alkali feldspar from felsic, syenogranitic magma into more mafic magma, causing local undercooling in the portion of mafic magma surrounding the crystals. This resulted in the growth of cellular plagioclase, with quartz infilling, in a thermally and compositionally equilibrating system.