Spatiotemporal variability of water quality in the Yertys River: evidence from a dataset of two sampling campaigns

Description

The dataset contains hydrochemical and toxicological measurements of surface waters collected from the Yertys River basin in eastern Kazakhstan during field campaigns conducted in 2018 and 2019. Sampling covered the main channel of the Yertys River, selected tributaries, and two major reservoirs within the basin, namely the Bukhtarma Reservoir and the Shulbinsk Reservoir. In total, 22 monitoring sites were investigated, including six sites located along the main river channel, fourteen tributary sites, and two reservoir sites. For each monitoring station, the dataset includes sampling location, geographic coordinates (latitude and longitude in WGS84), sampling year, and measured concentrations of physicochemical and toxicological parameters. The data contains 37 measured variables grouped into several categories: (i) physical parameters include water temperature (°C); (ii) general hydrochemical indicators comprise pH, dissolved oxygen concentration (mg/L), dissolved oxygen saturation (%), and permanganate oxidizability; (iii) major ion composition includes bicarbonate, sulfates, chlorides, calcium, magnesium, sodium, potassium, and total dissolved ions (TDI); (iv) toxicological indicators include concentrations of heavy metals such as copper, zinc, lead, cobalt, nickel, cadmium, and manganese (Mn). In addition, concentrations of eight PCB congeners (PCB-44, PCB-49, PCB-74, PCB-85, PCB-86, PCB-97, PCB-128, and PCB-155) and total PCB concentrations are included. The hydrochemical composition of river waters shows pronounced spatial variability within the basin. Upstream mountainous tributaries are generally characterized by calcium–bicarbonate water types associated with natural weathering processes of carbonate and silicate rocks. In downstream sections influenced by mining, metallurgical, and industrial activities, elevated sulfate and chloride concentrations are observed, indicating increasing anthropogenic impact on water chemistry. Tributaries affected by industrial regions, including the Ulba and Glubochanka rivers, exhibit comparatively higher mineralization and trace metal concentrations. “NA” means not analysed, while concentrations below analytical detection limits are marked as “ND” (not detected). The dataset can support studies related to hydrochemistry, environmental monitoring, pollution assessment, geochemical processes, ecological risk analysis, and transboundary water resource management in Central Asia. It may also serve as a baseline reference for future long-term monitoring and comparative studies of river water quality in the Yertys River basin.

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Funders

• Science Committee of the Ministry of Science and Higher Education of the Republic of Kazakhstan

  Grant ID: АР26103691 "Ecosystem Assessment of Pollution and Sustainability of the Aquatic Environment in the Buktyrma Reservoir Using Innovative Methods and Development of Recommendations for Maintaining Water Quality”

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