Nitrogen behavior in the shallow groundwater–soil system within agricultural landscapes

The research is devoted to the analysis of the changes in the chemical composition of shallow groundwater within the agricultural landscapes of the Poyang Lake area taking into account the peculiarities of soil composition. The analysis is based on field data collected during 2011–2017 by the sampling of the shallow groundwater from the private and public wells and adjoining soils. Correlations between the content of the N-compounds and the Eh values in autumn as well as a relationship of the NH4+ concentration with the DOC content reflect the processes of the organic matter transformation in the aquifer. Correlations between the N content in the upper soil horizon and the concentrations of the N-compounds in the shallow groundwater indicate a strong connection of the origin of the groundwater chemical composition with the soil composition

Size fractionation of trace elements in the surface water and groundwater of the Ganjiang River and Xiushui River basins, China

The research of trace element behaviour and size fractionation is significant to understand the processes in the water-rock system. Moreover, the aqueous speciation of trace elements is strongly related to their distribution and toxicity. In this research, trace elements behaviour and their size fractionation are investigated in the natural water (the surface water and shallow groundwater) of the Ganjiang River and Xiushui River basins. Trace element concentrations were measured by ICP-MS. The authors estimated the size fractionation of the trace elements between suspended forms (>0.45 [mu]m) and dissolved fractions, which included truly dissolved (1 kDa) and colloidal particles (0.45 [mu]m-1 kDa)), after filtration through a 0.45 [mu]m acetate cellulose membrane filter. The distinct features of the trace element size fractionation were identified. The size fractionation of the trace elements under different conditions (in the surface water and shallow groundwater) was studied

Water–rock interaction within the oligotrophic peat bog (part of the Vasyugan Swamp, Western Siberia)

Geochemical conditions of the formation of various minerals were studied within the oligotrophic pine-shrub and sphagnum peat bog. It was shown that at least two complex barriers function within the peat deposit. These barriers correspond to the changes in the advective and diffusion transfer of substances and promote the immobilization of Fe and a number of other chemical elements. The upper complex geochemical (redox, sulfide and sorption) barrier occurs approximately at the depths of 0.40 to 1.25 m. The lower complex geochemical (alkaline and sorption) and mechanical barriers are located at the bottom part of the peat deposit (the depth of 2.25–2.50 m)

Predicting potential pollutant release from waste rock at the abandoned Beck mine (Karelia, Russia) by equilibrium kinetic modeling

The Beck mine, located in the Republic of Karelia, Russia, is an abandoned mining site with significant potential for environmental contamination due to the presence of potential pollutants in its waste rocks. In this study, we investigated the chemical composition of mine waters and waste rocks and developed a theoretical model to understand waterrock interactions and the release of potential pollutants. Water samples collected from various locations on the Beck mine property were analyzed for chemical composition and showed low concentrations of total dissolved solids with pH values ranging from 6.42 to 7.74. The chemical composition of natural waters was determined by ICP-MS, ICP-AES, ion chromatography, potentiometric titration, and spectrophotometry. Equilibrium kinetic modeling was used to simulate water-rock interactions. The model predicted the concentrations of major and trace elements, demonstrating that dissolution-precipitation and complexation are the primary mechanisms shaping the chemical composition of mine waters. The dynamics of dissolution-precipitation of Fe-containing minerals highlighted the importance of the duration of water-rock interaction, with stagnant mine waters exhibiting higher concentrations of heavy metals. In addition, the presence of dissolved organic matter played a critical role in the accumulation of iron and arsenic in the studied mine waters. Overall, this study highlights the utility of equilibrium kinetic modeling in understanding the behavior of heavy metals during water-rock interactions and provides valuable insights into the potential environmental impacts of abandoned mine sites such as the Beck mine

Preliminary studies of surface water quality in Damodar River basin (West Bengal, India)

The purpose of the research was to study the main parameters of the chemical composition of surface water and its quality in the Damodar River basin near the Durgapur city where the surface water is used for water supply of the local community. During fieldwork water of the Damodar River, its tributaries (Tamla River and small streams - receivers of industrial wastewater and drainage water) and the Maithon Reservoir was sampled from the layer 0.1-0.5 m. Preliminary studies have shown that the main pollutants in the study area are organic compounds, ammonium, phosphate and fluoride ions. Deterioration of water quality in some sampling points is connected with a low content of dissolved oxygen and high concentrations of nitrite, chloride and sulfate ions

Preliminary studies of surface water quality in Damodar River basin (West Bengal, India)

The purpose of the research was to study the main parameters of the chemical composition of surface water and its quality in the Damodar River basin near the Durgapur city where the surface water is used for water supply of the local community. During fieldwork water of the Damodar River, its tributaries (Tamla River and small streams - receivers of industrial wastewater and drainage water) and the Maithon Reservoir was sampled from the layer 0.1-0.5 m. Preliminary studies have shown that the main pollutants in the study area are organic compounds, ammonium, phosphate and fluoride ions. Deterioration of water quality in some sampling points is connected with a low content of dissolved oxygen and high concentrations of nitrite, chloride and sulfate ions

Thermodynamic modeling of aqueous migration of chemical elements in irrigation water

Research of migration forms in irrigation water of flooded fields contributes to understanding geochemical barrier formation and functioning. It can improve pollution and nutrification control in the soil-water-plant system since geochemical barriers promote concentrating chemical elements at different depths of a soil cross-section. The research aimed to simulate the aqueous migration of chemical elements and their precipitation in the flooded rice fields’ irrigation water to determine the potential of removing them from the solution at the sorption geochemical barrier. The samples of irrigation water were taken after harvesting in the Poyang Lake basin (China) and analyzed with a standard set of methods for natural water, including ICP-MS and ICP-AES. To assess the migration forms, the HCh software package was used. The thermodynamic values database was supplemented with free energies of formation of metal complexes with fulvic and humic acids for standard conditions. Modeling has shown that most of the considered chemical elements migrate in positively charging simple ions. The main agents of complexation with humic substances are Fe, Ca, and U. Kaolinite potentially precipitates from the irrigation water. Results show that sorption of positively charged simple ions and MoO42− on clay minerals should be under special attention

Nitrogen behavior in the shallow groundwater–soil system within agricultural landscapes

The research is devoted to the analysis of the changes in the chemical composition of shallow groundwater within the agricultural landscapes of the Poyang Lake area taking into account the peculiarities of soil composition. The analysis is based on field data collected during 2011–2017 by the sampling of the shallow groundwater from the private and public wells and adjoining soils. Correlations between the content of the N-compounds and the Eh values in autumn as well as a relationship of the NH4+ concentration with the DOC content reflect the processes of the organic matter transformation in the aquifer. Correlations between the N content in the upper soil horizon and the concentrations of the N-compounds in the shallow groundwater indicate a strong connection of the origin of the groundwater chemical composition with the soil composition

Water–rock interaction within the oligotrophic peat bog (part of the Vasyugan Swamp, Western Siberia)

Geochemical conditions of the formation of various minerals were studied within the oligotrophic pine-shrub and sphagnum peat bog. It was shown that at least two complex barriers function within the peat deposit. These barriers correspond to the changes in the advective and diffusion transfer of substances and promote the immobilization of Fe and a number of other chemical elements. The upper complex geochemical (redox, sulfide and sorption) barrier occurs approximately at the depths of 0.40 to 1.25 m. The lower complex geochemical (alkaline and sorption) and mechanical barriers are located at the bottom part of the peat deposit (the depth of 2.25–2.50 m)

Isotopic composition ([delta]{18}O and [delta]D) of the shallow groundwater in the Poyang Lake basin

The article is focused on the identification of evaporation and other natural processes which affect the isotopic composition of shallow groundwater in the Poyang Lake basin, such as water-rock interaction and mixing of the shallow groundwater and surface water. For this purpose the dual isotope approach ([delta]D–H[2]O and [delta]{18}O–H[2]O) was used. The samples were collected from domestic wells around the Poyang Lake. The value of [delta]D obtained for the shallow groundwater ranges from -21.5 to -42.6/. The [delta]{18}O value varies from -3.5 to -7.1/. It was found that the shallow groundwater of the Poyang Lake catchment is of meteoric origin. The influence of evaporation on the isotopic composition of shallow groundwater is negligible and observed mainly during the dry season. The deviation from the local meteoric water line, especially during the rainy season, may be explained by the processes in the water-rock system, but this issue is required further research