Hydrogeochemical features of the groundwater in the Bodrak river basin (Kachinskoe Uplift Mountain Crimea)

The hydrogeochemical composition of groundwater in the Bodrak River basin (area of the geological practical studies and field works for students of SPbU, Lomonosov MSU, Dubna and Voronezh Universities) was investigated. The study determined role of lithology in the hydrochemical composition of groundwater and surface waters of the region. Three hydrochemical generations of groundwater have been identified by statistical analysis, geochemical features of groundwater in the region have been revealed, stable natural association of chemical elements in the groundwater of the Bodrak River has been obtained: Ba(2,0–58,2)–B(1,1–10,3)–Ag(3,2–8,6)–Sr(1,6–8,4)–Sn(3,4–4,9). The study analyzed the intensity of water migration of chemical elements in the groundwater and river waters of the Bodrak River, and the variability of the water migration coefficient was obtained along the river.

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.

Distribution of heavy metals in cutover peat bog soils

The paper contains the research results on content of total and mobile heavy metals compounds (lead, cadmium, copper, and zinc) in soils of the cutover peat bog Zenginsky located in the central part of the Kirov Region. As a result of the conducted researches it is revealed that the content of elements in different peat layers in control site (zinc - up to 2,60; copper - up to 0,90; lead - up to 5,60; cadmium - up to 0,59 mg/kg of soil) does not exceed the level of their maximum-permissible concentration and background contents in soils of the Kirov Region. For the undeveloped site the increased content of total and mobile compounds of the studied metals in the top layers is noted; it can be caused by biogenous accumulation of these elements by plants. The developed soils (the drained sites) are characterized by considerable fluctuations of elements content both in different profiles, and in the different layers of the same profile. Here the maximum content of elements in separate layers is much higher than control (zinc - up to 126,0; copper - up to 34,0; lead - up to 17,0; cadmium - up to 1,2 mg/kg of soil). Economic use of the peat bogs leads to an active mineralization of the top part of the remained peat mass. As a result of these processes stability of biogeochemical cycles of separate elements is broken. At the same time, the received data allow to consider soils of control sites as indicators of surrounding environment condition. The good safety of peat deposits gives the opportunity to study processes of accumulation and migration of chemical elements.

FORMS OF THE MIGRATION OF CHEMICAL ELEMENTS IN THE THERMAL WATERS OF THE BANG DEPOSIT (CENTRAL VIETNAM)

Calculation results for the forms in which chemical elements migrate in the thermal waters of the Bang deposit (Central Vietnam) are reported for the first time. The studied waters are divided into two groups with respect to temperature: 24.3–34.5 оС for the first group and 62.1–97.1 оC for the second group. The first type relates to the waters of HCO3-Cl-Na-Mg composition, has very low mineralization (44–87 mg/dm3) and is characterized by рН from weakly acidic to weakly alkaline (5.71-7.84). The second type relates to the waters of HCO3-Na composition with total mineralization up to 256-659 mg/dm3 and рН from 8.03 to 8.51. Calculations of the forms of migration of chemical elements showed substantial differences in their behavior for two revealed groups. For example, in waters with the temperature of 24.3–34.5 оC, the dominating form is migration of free ions. For thermal waters with the temperature of 62.1–97.1 оC, migration of the elements in compounds with carbonates and sulfur is characteristic, as well as in the form of free ions.