Photochemical origin of reactive radicals and halogenated organic substances in natural waters: A review

2021 ◽  
Vol 401 ◽  
pp. 123884
Author(s):  
Yongxia Dong ◽  
Wenya Peng ◽  
Yunjiao Liu ◽  
Zhaohui Wang
1918 ◽  
Vol 11 (1-10) ◽  
pp. 557-571
Author(s):  
Morris Wells

Carbon monoxide and carbon dioxide are both present in the waste that is diverted into natural waters by many works where illuminating gas is manufactured and, since the waste as a whole is known to be exceedingly poisonous to aquatic organisms, the role played in its toxic action by the two gases in question was investigated at the time that the many other organic substances of which the waste is composed were studied by Shelford. The investigation has shown that both of the gases are poisonous to fresh-water fishes even when present in the water in relatively small proportions, but the monoxide has been found to be by far the more deadly of the two.


2021 ◽  
Vol 937 (2) ◽  
pp. 022060
Author(s):  
Denis Butko ◽  
Yana Lazareva ◽  
Marina Sharkova

Abstract The paper presents a study of quality of natural waters and water in a centralized water supply system during the period of an increase in the “Smell” indicator in the spring of 2021. The chemical and physical properties of water, the results of quality and quantity of studying the variety I phytoplankton in the most difficult period of deterioration in quality of river water. Low water and exceeding MPC concentrations of organic substances in river water. The Don River causes altered form odorant substance as evidenced by the results of determination in water 1,2,3- t rihlorbenzol and geosmin, hexachloroethane and aniline shown in operation. Barrier function of reagent treatment methods used at water treatment plants in the lower reaches of the river. The Don River, even when combined with carbonated water, is deficient in odor-producing substances.


2021 ◽  
Author(s):  
Marina Dinu

<p>The reactions of toxicants with organic substances of a humic nature are complex and depend on many geochemical factors. Differences in the mechanisms of the selected toxicants binding with organic natural substances of various natural waters - atmospheric precipitation, lake waters (acidic and alkaline), lysimetric waters are especially interesting. Due to significant concentration differences, features of functional groups and size distribution of components, the inactivation features of humic substances are selective and highly variable. We studied the waters of an acid lake near the city of Valday (Valday National Park, conditionally a background lake) and alkaline lake Valday (city of Valday, local technogenic influence). Near each lake there was a sediment collector (a container for collecting atmospheric precipitation) and a lysimeter (a container under the soil for collecting soil moisture) under the humus horizon (about 20 cm). Particular attention was paid to soil (lysimetric) waters with varying degrees of anthropogenic impact. We considered the behavior of a large group of heavy metals, as well as benzopyrene. To assess the composition and qualitative features of organic substances, gas chromatography-mass spectrometric methods of analysis were used. Chromatographic methods were used to assess the molecular weight distribution of the components. Possible reaction mechanisms were studied by IR spectral methods. Evaluation of the reactivity of organic substances was carried out by the methods of dynamic light scattering (zeta potential, MM, size) using the "Zeta-sizer nano". In addition to humic substances in the waters, the contents of autochthonous organic matter were estimated, especially in an alkaline lake, which in some periods prevailed over humic ones. In addition to humic substances in the waters, the contents of autochthonous organic matter were estimated, especially in an alkaline lake, which in some periods prevailed over humic ones. For separation, exchange technique and fluorometric evaluations were used. We conducted research in the period 2015-2020, sampling was carried out in spring, summer, autumn. Thus, we studied the circulation (in miniature) of changes in the protective properties of humic substances, depending on a large number of factors.</p>


Vestnik MGSU ◽  
2019 ◽  
pp. 1180-1195
Author(s):  
Yu Dan Su ◽  
Alexei G. Pervov ◽  
Xuan Quyet Nguyen

Introduction. In this paper, we investigate the interaction of organic pollutants with nanofiltration and reverse osmosis membranes in natural water on the basis of experimental data and available literature information. The rates of formation of various organic deposits (humic acids changing the water colour and forming low-molecular organic compounds characterised by an oxidation index) on membranes during purifying river and pre-treated water are presented. Aim: To determine the required efficiency of removing organic substances from surface waters at the pre-treatment stage prior to water treatment by reverse osmosis on the basis of measuring the rates of adsorption of organic substances on membranes and predicting the amount of as-formed organic deposits. Methods and materials. Methods for determining the adsorption rate of organic pollutants using gas-liquid chromatography and total carbon determination are described. The advantages of spectrogram analysis in assessing water quality are specified. The formation rates of high- and low-molecular organic substances, which produce colouring and characterise water oxidisability, respectively, were determined using a membrane test unit. Results. According to the rates of forming organic deposits on membranes both during the processing of river water with a colour of 60 PCU and purified (tap) water with a colour of 18 PCU, organic substances adsorbed on membranes are shown to have little effect on the efficiency of the reverse osmosis process. In addition, the rate of depositing organic substances on the membranes under study is established to be significantly lower than that using sparingly soluble salts (calcium carbonate). Conclusion. Our results demonstrate that organic deposits formed on the membranes under study have an insignificant effect on the membrane performance. Therefore, pre-treatment aimed at removing organic substances when purifying natural waters with colour indices of up to 60 PCU is not required.


2021 ◽  
Vol 99 (12) ◽  
pp. 1365-1369
Author(s):  
Ivan A. Hlystov ◽  
Tat’yana N. Shtin ◽  
Vladimir B. Gurvich ◽  
Elena A. Kuz´mina ◽  
Aleksandra V. Bugayeva ◽  
...  

Introduction. Increased content of organic substances in natural waters, expanding the list of input substances to water bodies, owing to industrial and economic activities of a person, and climate changes is an urgent issue. Against this background, compounds with unknown chemical and toxic properties are likely to appear. The purpose of this study is to collect data concerning the ways for organic compounds entering water bodies and the human body, study data on interaction mechanisms of organic substances with metals, reveal the fate of known organic chelators, complexing agents as well as organometallic compound shaped by them inside the body. The literature search was carried out in Scopus, Web of Science, CyberLeninka databases. Sources of organic substances entering water bodies, properties of organic substances. There are three types of organic substances in water bodies, divided by the sources of their occurrence (inflow): terrigenous origin, shaped inside water bodies and coming from man-made sources. Organic compounds may produce soluble and insoluble compounds with metals and colloids. Mechanisms of interaction of organic substances with metals. Bonding of organic substances takes place by the type of chelation and complexation. There are factors for bonding: functional group content, the molecular mass of substances, ion radius, and competitive interaction with binding sites. Substances having binding properties include phenolic compounds, carboxylic acids, polysaccharides, and flavonoids. Considering that phenolic compounds are located in large quantities in plant and animal tissues, this group of compounds has been researched more thoroughly in terms of interactions with metals and toxicometry. Intake of organic and organometallic compounds into the body, their kinetics, metabolism and decay. Organic compounds, chelates, and complexes enter the body with drinking water, food, and drugs. They are also generated in the body, including by replacing ions. Data on biochemical and toxicological studies of currently known compounds is given


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