DISTRIBUTION OF THE FORMS OF MERCURY OCCURENCE IN THE PROFILE OF TYPICAL SOILS OF SOUTH SIBERIA

The article presents original data on the gross concentration of Hg in typical soils of steppe and forest-steppe landscapes, lacustrine-accumulative plains, as well as systems of intermontane depressions in Southern Siberia. Quantitative estimates of the distribution of Hg in soil profiles in the Tomsk Region, Altai Territory, and the Republic of Buryatia. The features of the distribution of Hg concentrations in soil profiles depending on the particle size distribution, hydrogen index, electrical conductivity and magnetic susceptibility were revealed. The forms of occurrence of Hg in soil profiles of different types of soils have been determined. In the studied soil types, the largest proportion of Hg falls on forms that evaporate in the temperature range 170-4000C, i.e. highly volatile low molecular weight organomercury compounds, HgCH3, Hg (CH3) 2), HgCl2, HgS alkyl radicals, aryl radicals, as well as in organo complexes. These forms are the most accessible and toxic for living organisms, the proportion of inaccessible and inert forms is minimal.

Neutral and cationic cyclic (alkyl)(amino)carbene mercury [cAAC–Hg(ii)] complexes: scope of hydroamination of alkynes with organomercury compounds

[cAAC·HgBr(μ-Br)]2 catalyzed intermolecular hydroamination of phenylacetylenes with anilines has been demonstrated under mild conditions.

Action of Some Organomercury Compounds on Photosynthesis in Spinach Chloroplasts

The effects of five organomercury compounds (methylmercuric chloride, phenylmercuric acetate, phenylmercuric borate, phenylmercuric citrate and diphenylmercury) on photosynthetic electron transport (PET) in spinach chloroplasts were investigated. The IC50 values of organomercury compounds related to PET inhibition in spinach chloroplasts varied in the range from 468 mmol dm-3 to 942 mmol dm-3 and were approximately by one order higher than the corresponding value determined for HgCl2 applied also in DMSO solution (IC50 = 58 mmol dm-3). Due to extremely low aqueous solubility of diphenylmercury, the corresponding IC50 value could not be determined. Using EPR spectroscopy as probable sites of action of organomercury compounds in photosynthetic apparatus ferredoxin on the acceptor side of PS 1 and the quinone electron acceptors QA or QB on the reducing side of PS 2 were suggested.