Both the insufficiency of water resources and the contamination of even transboundary water bodies are serious problems. Water quality analyses of the transboundary (between Russia and Kazakhstan) Ural River and the Kazakh sector of the Caspian Sea, and their assessment are the main research questions of this study. It is shown that the Ural River is heavily contaminated by polychlorinated biphenyls, heavy metals, oil contaminants, and pesticides, arising from industrial enterprises and agricultural objects. The results show that these toxicants are not only present in water, but they are also accumulated in the muscular tissues of all fish (Abramis brama, Sander lucioperca, Aspius aspius). The Caspian Sea is heavily contaminated by petroleum hydrocarbons due to off shore oil production. A sufficiently high level of accumulation of petroleum hydrocarbons, organochlorine pesticides and heavy metals was determined in the muscles of Caspian fish. All these contaminations lead to the loss of biodiversity and bio-productivity of the Caspian Sea. The authors propose a methodology for a quantitative assessment of the environmental safety level in relation to the Kazakh part of the Caspian Sea, based on bioindication methods. Recommendations, aimed for maintaining acceptable values of water resources quality, are suggested.

The huge decrease in water volume in the Aral Sea, which was caused predominately by enormous water withdrawals from the Aral Sea tributaries, has changed the former world’s fourth-biggest inland lake into a new desert called Aralkum. Due to its long-term use in agriculture, persistent organic pollutants (POPs), including organochlorine pesticides (OCPs), and polychlorinated biphenyls (PCBs) play a special role in the pollution of the Aral Sea tributaries and in the Aral Sea itself. For the first time, POPs, OCPs, and PCBs were studied in the Large Aral Sea, Small Aral Sea, and the Syrdarya River. PCBs and OCPs in the collected water samples were analyzed using gas chromatography. The results of long-term and inter-annual analyses of POPs in water resources of the Kazakh part of the Aral Sea–Syrdarya Basin are presented. The analyses covered the Large and Small Aral Seas, the Syrdarya River, reservoirs, lakes of the river delta, and drainage water of the collectors from irrigation areas. The inflow to the Syrdarya River that came from the collector–drainage water was the main cause of water pollution. The pollution levels of toxic compounds, including the trends of temporal and spatial changes in pollutant concentrations, were analyzed and assessed. The latest studies from 2021 and 2022 show a decrease in pesticide concentrations by tens and hundreds of times.

In the context of sustainability, the concept of balanced development is crucial at both global and regional levels. This principle is equally significant for specific regions, natural-economic complexes, and local communities. Sustainable regional development necessitates a holistic approach to addressing economic, social, and environmental challenges, which are particularly pertinent at the regional scale. The sustainable development of nations is intrinsically linked to their integration into global processes; however, its resilience and stability are contingent upon balanced regional progress. The West Kazakhstan region exemplifies an economic powerhouse within the country and plays a pivotal role in national regional policy. This study introduces a conceptual model designed to evaluate sustainable development through the balanced interaction of various indicators. The results reveal a disparity between the financial and economic potential of different regions and their environmental challenges. These findings form the foundation for developing a new paradigm of sustainable development that emphasizes the integration of economic growth, social stability, and environmental security. The proposed model has the potential to be adapted in various regions of the world facing similar climatic, water, and social challenges. However, it is necessary to consider local characteristics, data availability, and institutional contexts.

In the context of sustainability, the concept of balanced development is crucial at both global and regional levels. This principle is equally significant for specific regions, natural-economic complexes, and local communities. Sustainable regional development necessitates a holistic approach to addressing economic, social, and environmental challenges, which are particularly pertinent at the regional scale. The sustainable development of nations is intrinsically linked to their integration into global processes; however, its resilience and stability are contingent upon balanced regional progress. The West Kazakhstan region exemplifies an economic powerhouse within the country and plays a pivotal role in national regional policy. This study introduces a conceptual model designed to evaluate sustainable development through the balanced interaction of various indicators. The results reveal a disparity between the financial and economic potential of different regions and their environmental challenges. These findings form the foundation for developing a new paradigm of sustainable development that emphasizes the integration of economic growth, social stability, and environmental security.