Hypericum perforatum L. and Achillea millefolium L. are plants which can be characterized as heavy metal accumulators. Including relating soils samples differing in pH reaction, 14 samples of St. John's wort and 9 samples of yarrow were collected from different localities in Yugoslavia and Republic Srpska. The total heavy metal content (Mn, Zn, Cu, Pb, Ni and Cd) was determined in the collected herb material (for St. John's wort-25 cm from the top of plant and for yarrow-30 cm) by standard analytical methods. Heavy metal content in the herb mostly dependent on soil composition, for both species. Concentration of Mn and Zn in the herb decreased linearly with the increase of soil pH (Mn: r =-0.62* for yarrow and r =-0.66* for St. John's wort; Zn: r =-0.71* for yarrow and r =-0.62* for St. John's wort), while Cd concentration decreased exponentially (r =-0.77* for yarrow and r =-0.58* for St. John's wort). Cd content in St. John's wort was mostly above limit of 0.5 ppm when soil pH (in nKCl) was lower than 5.9, and 4.5 for yarrow. Higher Cd content in the yarrow herb, and especially St. John's wort herb from acidic soils, points to significance of: 1. Required control of Cd content in the raw materials collected in the wild and 2. Necessary avoidance of such soils for cultivated production of those species. A relationship of Ni content in the herb with soil pH was found only for St. John's wort (r =-0.80***). Correlation between heavy metal content in the herb and humus content in the soil was analyzed but statistically significant regression coefficients were not obtained. Positive linear dependence was found between Pb and Ni content in the herb and their total content in the soil, for Achillea millefolium L. (r = 0.88** and r = 0.65*, respectively), which can be explained by the origin of the samples. Also, there is increase of Cu, Pb and Ni content in the yarrow herb with the increase of their available content in the soil (r = 0.67*, r = 0.88**, r = 0.65 *, respectively), while such dependence was obtained only for Pb content in St. John's wort herb (0.56*).

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Bentonite samples from Petrovac and Aleksinac were treated with sulfuric acid of different molarities. Differences in structure and texture of the initial and modified bentonite were determined by chemical analysis and Xraypowder diffraction (XRPD), infra-red spectroscopy (FTIR), scanning electron microscopy (SEM) and physisorption nitrogen at −196°C. Sulfuric acid caused an exchange of Al3+, Fe3+ and Mg2+ with H+ ions which led to a modification of the smectite crystalline structure. The Mg and Fe substitution in the octahedral sheet promoted the dispersion of those layers and forming of amorphous silicon. The sequence according to which the cations left the octahedral sheets was as follows: Mg2+>Fe3+>Al3+. The sulfuric acid activated bentonites exhibiting a lower cation exchange capacity (CEC) and а change of specific surface area (SBET) from 6 to 387 for bentonite from Petrovac and from 44 to 1784 m2 g-1 for bentonite from Aleksinac, positioning them as an excellent absorber in wine technology and in the protection of soil and environment

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