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The effect of microstructure modifiers, Sn and Ag, on the corrosion rate of commercial Pb-Ca alloy in H 2 SO 4 electrolyte was investigated by the potentiodynamic polarization and by the weight loss corrosion rate measurement at the open circuit potential. The effect of microstructure modification of the Pb-Ca alloy, provoked by the alloying with tin and silver as well as by the proper thermo-mechanical treatment, is recorded by optical microscopy. The weight loss experiments have shown three-to five-fold decreases in the corrosion rate of ternary Pb-Ca-Sn and quaternary Pb-Ca-SnAg alloys, compared to the results for primary Pb-Ca alloy. It is largely in accordance with the results of potentiodynamic polarization measurements that showed comparable decrease in the passive current density of the modified alloys. The obtained results are discussed in terms of the synergetic effect of the addition of modifiers and the thermo-mechanical treatment on to the Pb-Ca alloy microstructure refinement, and accordingly the increase in their corrosion resistance.

Zinc, copper, iron, chromium and cobalt are essential elements for human health, showing toxicity only in high concentrations, while lead and cadmium are extremely toxic even as traces. Therefore, it is important to monitor the contents of toxic metals in vegetables. Large number of vegetables is grown and used in nutrition, in Kosovo. The concentrations of selected elements in vegetables (radish, onion, garlic and spinach) from Kosovo were determined using ICP-OES method. Oral intake of metals and health risk index were calculated. Statistical analysis indicated numerous positive correlations between concentrations of selected elements in vegetables. As a result of principal component analysis, 15 new variables were obtained which were characterized by eigenvalues. The sequence of health quotients for the heavy metals followed the decreasing order Zn = Mn > Pb > Cu > Ni > Fe > Cd > Co > Cr. The health quotients for all investigated heavy metals were below 1 (one), which is considered safe. The vegetables from Kosovo are mainly safe for use in everyday diet.

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The dependence of disproportionation reaction kinetics of iodous acid, HOIO, in aqueous solutions of sulfuric acid on the solution acidity is examined. The rate constants of the disproportionation reaction are determined at temperatures of 18, 25 and 30°C, based on kinetic data obtained under stationary conditions. The average value of the activation energy is determined to be 42 kJ/mol.