Chemistry Journal of Moldova. General, Industrial and Ecological Chemistry

21-26

Authors: Tudor Spataru, Francisco Fernandez

The hydrogen molecule interaction with CpCr (CO)3 catalyst has been studied using the B3LYP, B86 functionals and the 6-311++G** , LACV3P basis sets. The best results in the testing calculations of the analyzed reaction have been obtained by using the B86/6-311++G** DFT version giving quite good agreement between experimental and theoretical calculated enthalpies. The dispersion corrected DFT Grimme’s and Head-Gordon and coworkers’ functionals have been attempted without any improvement of the results. The free energies of the initial reactants, transition states, intermediate compounds and final products of the typical six-ring bond modification mechanism have been calculated. The energy barriers of the reaction pathways are too high in the DFT approximation.

29-39

Authors: S.P. Li., R.P. Koroleva, K.A. Kydralieva, and Sh.J. Jorobekova

This research demonstrated development and properties of detoxicants of integrated effect based on humic derivatives. Set of samples of humic-based derivatives including carbonylated, hydrophobizated, oxygenated, cryodestructed and biosolubilized have been synthesized. It has been demonstrated that all the produced detoxicants possessed plant growth promoting activity and detoxifying potential in relation to heavy metals.

50-53

Authors: Popov Leonid, Ciudin Gheorghe, Rotaru Serghei

The Republic of Moldova is endowed with fertile soils. Soil pollution is a major concern since no effective treatment method exists to restore the natural qualities of the soils. Polluted soil can only be rehabilitated under the long-lasting influence of natural factors.A major source of anthropic impact on soils is the application of fertilizers and pesticides in agriculture. At the same time, manure and livestock excreta often are transported to communal dump sites, where they are mixed with other wastes, or are left in ravines, along the local roads and in other unauthorized places. Instead of improving the soil productivity the nutrients find their way to and pollute the surface and ground waters.At the same time, pollution of the soils in the vicinity of former pesticide storehouses remains a problem. More than 200 storehouses have been dismantled during the last years and some of the remaining are in a poor condition, unfenced, unguarded, without doors and windows, thus being sources of chemical pollution. Moldovan soils are prone to erosion and this is how agrichemicals can travel to the water environment thus endangering water life and limiting water uses. Investigations found HCH and DDT residuals in bottom sediments from several reservoirs and lakes as well as the main rivers, Nistru and Prut (concentrations ranged between 0.2 and 15.8 ppb). The concentration of PCBs in the topsoil collected beneath the capacitors battery at the Vulcănesti substation reached a level of 7100 ppm which is exceeding the MAC by five orders of magnitude (!). With no exception, allowable concentrations of PCBs in soil were exceeded also on the territory of other investigated substations, with peaks registered at the Briceni substation (2545 ppm) and the Orhei substation (1959 ppm). The degradation of soils implies the reduction or total loss of their biologic or economic productivity caused by anthropic or natural processes.

56-69

Authors: A.B. Yankauskas, S.N. Lukashenko, A.A. Amirov, P.V. Govenko

The ecological situation in the former Semipalatinsk test site is characterized by a combination of both radiative and “nonradiative” factors. There were investigated near-portal areas of the tunnels with water seepage at “Degelen” site. All the tunnel waters are characterized by higher concentrations of uranium, beryllium, and molybdenum. The watercourse of the tunnel # 504 is unique for its elemental composition, in particular, the content of rare earth elements, whose concentration in the water is in the range n*10-5 – n*10-7 %. Of all the rare earth elements in the samples were found 13, the concentrations of aluminum, manganese, zinc are comparable to the concentrations of macro-components. Concentration of 238U in the studied waters lie in the range of n*10-4 – n*10-6 %, which suggests the influence of uranium, not only as a toxic element, but its significance as the radiation factor. The analysis of complex data obtained showed that the elevated concentrations of heavy metals in the soils of the areas under study, as a rule, are a consequence of the carry-over of these metals by water flows and their subsequent deposition in the sediments.

74-77

Authors: Armen Saghatelyan, Lilit Sahakyan, Olga Belyaeva

This research is focused on the level of heavy metal contents in dust of a near-ground layer of atmosphere. The dust load level was evaluated as medial. Indicated was a quality composition of dominating dust pollutants. The level of summary load of metals was low.

83-90

Authors: Burlakovs Juris, Vircavs Magnuss

Waste and the pollution of ecosystems are direct consequences of the use of resources for the modern society development. Waste dumps are evident witnesses of former economic and industrial management without sustainable waste management planning. Particular attention in this article is paid to the research of two waste dumps in the capital city of Latvia – Riga, which are planned to be re-cultivated in the nearest future and one site, which is former toxic hazardous soil dump site, where the remediation of site is of priority need. Waste dumps, mentioned in the article below, were created without environmental planning and in many cases the location of waste dumps are very problematic for secondary use of dumped material, remediation and re-cultivation. The present study is giving a general overview of contamination level in two waste dumps in Riga, which were made in the period from 50-ties to 70-ties of the 20th century, also the case of hazardous soil dump site formed in a period of more than 100 years is described. Planned actions as well as direct remediational technologies to reduce the poisonous impact to the urban environment and the role of recultivation in the urban planning in general are proposed. The fate of contaminants, including heavy metals, macrocomponents, oil products, various chemicals and other chemical oxygen demand (COD) and biological oxygen demand (BOD) agents must be estimated in the process of re-cultivation. Special technologies can be applied such as: a) in-situ and ex-situ technologies – excavation with separation and concentration of valuable materials, stabilization/ solidifi cation of some areas in site and out of site; b) in-situ technologies – soil as the infi ltrate source fl ushing for groundwater contamination level diminishing, barriers/ treatment walls around the waste dump areas, chemical treatment and phytoremediation; c) ex-situ technologies – soil washing and bioremediation in some cases. Legislative aspects as well as the possible land remediation technologies for reduction of the waste dump generated contamination in Latvia are also discussed.

95-97

Authors: Vladimir Kiriliuc

The scale of environmental regulation (content and pollution levels) of trace element in soils of Moldova was proposed. Contamination levels are justified, depending on the adverse effects that have trace elements in soils, plants, groundwater and more - per person. Proposed scale has 6 content and 4 pollution levels. Along with equalized MPC it may help to consider a number of deficiencies that are met in this area and improve the practical application of the assessment of soil contamination. Scale Indicators are flexible values, taking the large variability content of trace elements.

104-106

Authors: V.M. Nikolskiy, L.N. Tolkacheva, Ya.M. Khalyapina, T.I. Smirnova, A.A. Yakovlev

In the laboratory and plot experiments the effect of ethylenediaminedisuccinic acid (EDDS) and iminodisuccinic acid (IDS) on chlorophyll content in wheat germ leaves and adult plants was investigated. It was estimated that both complexons increased chlorophyll content in leaves and crop yield.

110-114

Authors: Ecaterina Emnova

The aim of this research was to assess how biochemical processes driven by microbial activity and extracellular enzymes have developed in the long-term under farming system with different fertilizer and crop types. It was concluded that the crop types had a more considerable impact on the soil biochemical processes compared to long-term Org or mixed Min+Org fertilizers amendments.

122-123

Authors: Violeta Elena Copcia, Ion Sandu, Nicolae Bilba, Simona Dunca

To guarantee the microbiological quality of the water, which has been affected by the pollution of the bacterium, it is necessary to implement a tertiary drinking system in the resident houses. A possible complementary system is the utilization of clay for treatment of drinking water.

129-132

Authors: Bilanchyn Yaroslav, Rezvaya Svetlana, Medinets Sergiy, Pitsyk Vasiliy

Results of chemical processes’ dynamic studies of many years (1971-2011) in the soils of Odessa Region have been described. The most signifi cant in the last 15-20 years have been changes of humus content and ecological & agrochemical status of black soils. In spite of some increase in the norm of fertilizers input for the last 5 years the negative balance of plant nutrition elements in soils is preserved. Ways of optimization of humus and ecological & agrochemical status of soils in the region and increase of their fertility have been proposed.

140-144

Authors: Andreea Stanila, Sorin Stanila

The [Cu(L)2]·H2O, [Co(L)2]·2H2O, [Zn(L)2]·H2O complexes with methionine (L) as ligand, were synthesized in water solution and analyzed by means of: elemental analysis, atomic absorption spectroscopy, thermogravimetry, FT-IR, UV-VIS and EPR spectroscopies. The atomic absorption spectroscopy and elemental measurements confi rm the ratio 1:2 metal ion: methionine composition for the synthesised compounds.The IR spectra show that amino acids act as bidentate ligands with coordination involving the carboxylic oxygen and the nitrogen atom of the amino group. Spectral UV-VIS data confirmed the covalent metal-ligand bonds, the pseudotetrahedral symmetry around the copper and zinc ions and the octahedral environment for the cobalt ion. Powder ESR spectra at room temperature are typically for monomeric species.

157-161

Authors: Nazarchuk G. І., Melnyk І. V., Zub Yu. L.

Spherical silica particles were synthesized by modified Stöber method using tetraethoxysilane and 3- mercaptopropyltrimethoxysilane (MPTMS). It was shown that their size (500-760 nm) depends on the nature of the catalyst used in the prehydrolysis of MPTMS (at constant alkoxysilanes ratio). Elemental analysis, thermogravimetry and IR spectroscopy data indicate the presence of thiol groups (2.8 mmol/g) in the surface layer. It was established that obtained nanospherical silica particles can adsorb Ag(I) ions from their acidified aqueous solutions.