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The effect of bottom sediments on the content of heavy metals in meadow soils

Kabzińska K., Szczesio M., Świętosławski J., Turek A.

Geology, Geophysics and Environment

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2015

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Vol. 41, no. 1

25--32

EN

The objects of the study were grasslands situated along the watercourse that collect matter directly from surface runoff from the surrounding fields and ditches. Therefore, the chemical composition of the bottom sediments can be varied. The aim of the study was to determine the content of anthropogenic fractions of selected heavy metals in meadow soils where the material from the watercourse maintenance was stored. Soil samples were collected along the banks of the Witonia “A” Channel (soil with sediment), and 30 meters from the watercourse (soil without sediment). The pH of soils without sediment was in the range 6.2–6.6, whereas the soil with sediment had a pH ≥ 7.0. The content of organic matter was 5.7–31.5%. The concentration of anthropogenic fractions of elements was determined by atomic absorption spectrometry after extraction with a (1 + 4) HCl solution. The anthropogenic enrichment coefficients (AEC) calculated in relation to the geochemical background level, were within the range: 0.9–2.8 for Zn, 1.2–3.5 for Cu, 0.7–3.1 for Pb, 1.0–2.8 for Ni and 0.3–0.9 for Cd. The AEC values for lead, copper, cadmium and nickel were usually higher in samples without sediment. A significant correlation between the metal and organic content ( R2 = 0.7–0.9) was found. On two sites, the level of heavy metals under investigation shows a significant local influence from anthropogenic pressure.

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Strukturalne zagadki kompleksowanych gramicydyn w ich kryształach

Główka M.L., Olczak A., Bojarska J., Szczesio M.

Wiadomości Chemiczne

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2007

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[Z] 61, 3-4

167-187

EN

Gramicidin D (gD) is a naturally occurring mixture of six linear pentadecapeptides produced by Bacillus brevis species in soil, which exhibit significant antibacterial activity against all Gram+ bacteria. The peptides are modified at both ends and the six forms differ at 1st (Val or Ile) and 11th (Trp, Phe or Tyr) positions. The most populated gramicidin A (VgA) has a sequence CH(O)-Val_1-Gly-Ala-D-Leu-Ala-D-Val-Val-D-Val-Trp-D-Leu-Trp_11-D-Leu-Trp-D-Leu-Trp-NHCH_2CH_2OH. Gramicidin was isolated in 1939 and its sequence was determined five years later. First models of its secondary structure based on helical conformation were proposed in 1971-1974 explaining channel-like properties of the peptide. Despite over 60 years of studies on gramicidin, there are still numerous unans-wered questions concerning its structure and functioning. Even fundamental issues of dimers type and handedness of helices in the gramicidin channel formed by the peptide in the bacterial cell membranes are not univocally accepted. After refining several crystal structures of gramicidin D complexes with alkali metal salts, we have at hands not only more facts concerning double-stranded antiparallel gramicidin dimers, but also new puzzled observations due to very high reso-lution data collected. These, among others, include visible asymmetry of cations' sites and occupations in the gramicidin channels, as well as specific arrangement of heterodimers in the crystals. The paper describes these interesting features of the complexed gramicidin structure and proposes some new explanations.

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Geometry of alfa-Diaryl Type CH-NH Acids of Pharmacological Interest. Crystal Structures of alfa-(4-Chlorophenyl)- and alfa-(2,4-Dichlorophenyl-alfa-2-pyrazilideneacetonitrilles

Główka M., Olczak A., Bojarska J., Szczesio M., Kozłowska K., Foks H.

Polish Journal of Chemistry

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2005

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Vol. 79 / nr 8

1275-1284

EN

alfa-Diarylacetonitriles represent a very interesting model for studying the structure-activity relationship, due to restricted freedom of conformational diversity and, on the other hand, a very wide range of biological activities, including analgesic, non-narcotic antiinflammatory and antirheumatic. The two studied representatives have in the crystal state very uniform molecular structures, which may be characterized by a dihedral angle between the two aromatic rings, being 77 graduate in 4-chlorophenyl; 74 graduate and 80 graduate in 2,4-dichlorophenyl derivative, respectively. Despite the presence of groups capable of weak C-H hydrogen bonds formation there is only one short C-H...X contact (X = N in 4 position of the pyrazinyl ring) of 2.40 ?, being significantly shorter than the sum of van der Waals radii of respective atoms. The contact found in the 2,4-dichlorophenyl derivative crystal is in accord with CH-NH proton transfer observed in these compounds.