Browsing by Author "Travin, Serghei"

Now showing 1 - 8 of 8

Climatic changes and surface water quality on Republic of Moldovas territory [Articol]
(Springer Nature Switzerland AG, 2020) Duca, Gheorghe; Nedealcov, Maria; Gladchi, Viorica; Travin, Serghei
The current state of global warming requires the expansion of the overall knowledge as well as regional particularities of climate change. The study finds that the Republic of Moldova is facing an accelerated pace of climate change that contributes to a more intense aridisation process and heat waves, with long periods of manifestation in the last years and argues that adaptation to the effects of climate change must be an important element for national policies and actions. Also, the authors establish that for Moldova climate change is a new challenge for water quality that requires great attention and a distinct scientific approach, which implies the participation of various domains of science. In this context, the study proposes an integrated knowledge based approach towards adapting to climate change effects in a broad context of natural and social systems, which incorporate scientific, legal, economic and ecological measures. The authors propose the development of plans and actions based on knowledge transfer and new technologies in order to achieve a better protection and adequate management of water resources in vulnerable areas.
Fotoliza directă a unor substanțe tiolice în mediul acvatic și rolul lor în procesele ecochimice din apele naturale [Articol]
(CEP USM, 2022) Lis, Angela; Gladchi, Viorica; Travin, Serghei
Fotoliza directă a unor substanțe tiolice în mediul acvatic și rolul lor în procesele ecochimice din apele naturale [Articol]
(CEP USM, 2022) Lis, Angela; Gladchi, Viorica; Travin, Serghei
Lucrarea prezintă rezultatele studiului fotolizei directe a unor substanțe tiolice de origine autohtonă și alohtonă în mediul acvatic și rolul lor în procesele ecochimice din apele naturale. Tiolii supuși fotolizei directe, la diferite surse artificiale de iradiere, au fost cisteina (Cys), glutationul (GSH), tioureea (TU) și acidul tioglicolic (ATG). Rezultatele obținute pe sisteme model indică asupra faptului că Cys, GSH și TU se supun fotolizei directe la acțiunea tuturor surselor de iradiere folosite în studiu. Vitezele de fotoliză directă și randamentele cuantice pentru Cys și GSH sunt foarte mici, pentru condițiile apropiate de celor din sistemele acvatice, respectiv această cale de degradare a lor în condiții naturale poate fi neglijată. Spre deosebire de Cys și GSH, TU se va supune fotolizei directe în condițiile sistemelor acvatice destul de efectiv, fapt confirmat și prin valorile randamentelor cuantice, care s-au dovedit a fi subunitare. Iar ATG, spre deosebire de celelate substraturi a demonstrat o stabilitate mai mare și nu s-a supus fotolizei directe, din cauză că spectrul de absorbție al acestuia nu se suprapune cu spectrele de emisie ale surselor de iradiere folosite în studiu.
Regional climate change and surface waters [Articol]
(2019) Duca, Gheorghe; Nedealcov, Maria; Travin, Serghei; Gladchi, Viorica
The actual period marred by the global warming requires expanding our knowledge on the regional particularities of climate changes manifestations as consequences of global climatic changes. It was stated that within the limits of Republic of Moldova’s territory the pace of warming is much more accelerated than the global one. These consequences, in their turn, had led to the increase in degree of evaporation of surface waters, which had conditioned the doubling of still water’s pollution in the region (Lake Beleu). We consider that the obtained results could contribute to the adequate management of water resources in the new climatic conditions.
Regional climate change and surface waters [Articol]
(Alexandru Ioan Cuza University Press, 2019) Duca, Gheorghe; Nedealcov, Maria; Travin, Serghei; Gladchi, Viorica
The actual period marred by the global warming requires expanding our knowledge on the regional particularities of climate changes manifestations as consequences of global climatic changes. It was stated that within the limits of Republic of Moldova’s territory the pace of warming is much more accelerated than the global one. These consequences, in their turn, had led to the increase in degree of evaporation of surface waters, which had conditioned the doubling of still water’s pollution in the region (Lake Beleu). We consider that the obtained results could contribute to the adequate management of water resources in the new climatic conditions.
Self-purification of aquatic media from hexachlorocyclohexane in a radical process [Articol]
(2019) Travin, Serghei; Duca, Gheorghe; Gladchi, Viorica
It is known, that highly toxic pesticide hexachlorocyclohexane (HCH) is resistant to decomposition and has a long-term accumulating capacity. Nevertheless, it undergoes complete degradation in reactions with hydroxyl radicals in Fenton-like systems. The goal of this work was to study the influence of HCH on the processes of radical self-purification of water bodies and to explain the mechanisms of chemical transformation of substances occurring in natural waters, as well as to reveal the kinetic characteristics of the processes of radical self-purification of water bodies. It was found, that HCH plays a dual role for aquatic ecosystems – it is not only a scavenger of free radicals, but also an additional initiator. Under the influence of light in the surface layer of water, HCH generates radicals, thus contributing to the self-purification processes.
Self-purification of aquatic media from hexachlorocyclohexane in a radical process [Articol]
(Institutul de Chimie al AŞM, 2019) Travin, Serghei; Duca, Gheorghe; Gladchi, Viorica
It is known, that highly toxic pesticide hexachlorocyclohexane (HCH) is resistant to decomposition and has a long-term accumulating capacity. Nevertheless, it undergoes complete degradation in reactions with hydroxyl radicals in Fenton-like systems. The goal of this work was to study the influence of HCH on the processes of radical self-purification of water bodies and to explain the mechanisms of chemical transformation of substances occurring in natural waters, as well as to reveal the kinetic characteristics of the processes of radical self-purification of water bodies. It was found, that HCH plays a dual role for aquatic ecosystems – it is not only a scavenger of free radicals, but also an additional initiator. Under the influence of light in the surface layer of water, HCH generates radicals, thus contributing to the self-purification processes.
Sensitized photolysis of thioglycolic acid in aquatic environment [Articol]
(Institutul de Chimie al AŞM, 2021) Lis, Angela; Gladchi, Viorica; Duca, Gheorghe; Travin, Serghei
It is known that thioglycolic acid (TgA) is widely used in industry and, unlike many other thiols, has a negative influence on organisms, similar to cysteine (Cys). The goal of this work was to study the TgA photochemical transformations in waters using model systems and to determine the kinetic parameters by varying the irradiation sources. It was found that TgA undergoes destruction on induced photolysis in the presence of humic substances (HSs), and its half-life can be estimated as 10-14 days, depending on weather conditions (cloudiness, time of day, season etc.). Results obtained in the course of this study on model systems were transferred to natural waters, and it was concluded that TgA has a positive influence on the chemical self-purification processes of water, in the natural aquatic environment. This is manifested by increasing the self-purification capacity of water, due to the generation of active oxygen species (ex.: O2¯•, •OH, 1O2), which lead to the degradation not only of this thiol, but of other pollutants present in aquatic environment, as well. At the same time, the products of the transformations are harmless to the aquatic environment and hydrobionts.