An electrochemical method is proposed for the modification of the surface of semiconductor gallium arsenide sensors. The electrochemical modification of the surface of GaAs-electrodes leads to the improvement of their electrochemical characteristics: an increase in the slope of the electrode function, a decrease in response time, and the extension of the concentration range. Potentiometric titration using unmodified and modified GaAs-electrodes for the determination of chlorides with silver nitrate in soil has been performed. The application of the modified sensors ensures the detection of the titration end-point with a higher accuracy.

—A general characteristic of the river basin of the interstate Ural River and data on the economic use of the Ural River in its upper, middle, and lower reaches are given. Information on the hydrology of the liquid and solid flow of the Ural River is presented. Hydrochemical monitoring of the water bodies of the Ural River basin was performed during the flood period, the summer low-water period, and the autumn low-water period in the years 2017–2018. The hydrochemical monitoring of the water quality in the natural water bodies of the Ural catchment basin has revealed an excess in the MPC of heavy metal ions in the water of the studied water bodies for drinking water and for fishery water bodies. An excess in the MPC of cadmium ions for drinking water by 1.2–1.4 has been recorded in the Ilek River during low water periods, as well as in the Ural River near the border with the Russian Federation in the amount of 3.1–3.4 MPC for drinking water during the flood period and near the village of Zharsuat in the amount of 1.5–2.6 MPC for drinking water during summer and autumn low water periods. An excess in the MPC of lead ions for fishery water bodies by 1.2–1.4 has been revealed in the middle and lower reaches of the Ural River in different seasons of the year. Excessive concentrations of ions of different heavy metals compared to their MPC for fishery water bodies have been found in all water bodies in different periods of the year. The greatest excess of zinc ions compared to the MPC for fishery water bodies was observed during the low water period.

A general characteristic of the river basin of the interstate Ural river and information on the economic use of the Ural river in its upper, middle and lower reaches are given. Information on the hydrology of the liquid and solid flow of the Ural river is presented. Hydrochemical monitoring of water bodies of the Ural river basin was conducted during the flood period, during the summer low water period and during the autumn low water period of 2017–2018. The hydrochemical monitoring of the water quality in natural reservoirs of the Ural drainage basin made it possible to identify an excess of the MPCs for residential use and for fishery of heavy metal ions in the water of the examined reservoirs. An excess of cadmium ions by (1.2–1.4) MPC for residential use was found in the Ilek river during its low water as well as in the Ural river near the border with the Russian Federation during the flood period in the amount of (3.1–3.4) MPC for residential use and near the village Zharsuat in the period of summer and autumn low water in the amount of (1.5–2.6) MAC for residential use. An excessive concentration of lead ions by (1.2–1.4) of MPC for fresh water fisheries in the middle and lower reaches of the Ural river at different times of the year was found. Excessive concentrations of ions of different heavy metals in comparison with their MPC for fresh water fisheries were found in all water bodies in different periods of the year. The greatest excess of zinc ions in comparison with its MPC for fresh water fisheries was observed during low water.

This study explores the use of diatomite from West Kazakhstan as a silica-containing raw material for borosilicate glass production. Three glass batches, based on quartz sand, chalk, and diatomite, were synthesized with varying ratios of network-forming and modifying oxides. Partial replacement of quartz sand with diatomite enabled glass melting at 1150 °C, producing a homogeneous melt. Glasses with higher diatomite content showed improved chemical and water resistance; specifically, the sample containing 52% diatomite achieved hydrolytic class III and water resistance class IV (XA = 1.0 cm³·g⁻¹), whereas quartz-based control samples corresponded to classes IV–V. Heat resistance ranged from 120 to 160 °C depending on composition. These findings demonstrate that amorphous SiO₂ and active oxides in diatomite promote a stronger three-dimensional glass network, highlighting the potential of locally sourced diatomite as an alternative SiO₂ source for sustainable, energy-efficient borosilicate glass production.