Aquatic Ecosystem Degradation Due to Industrial Pollution: A Case Study of the Okchu River

Abstract

State of the problem. Once recognized for its substantial hydropower potential of about 130 million kWh annually, the Okchu River is now classified among the most polluted rivers globally due to severe heavy metal contamination, making it unsuitable for human use without extensive treatment. The ecological degradation, mainly caused by copper-molybdenum mining in Armenia’s Gafan and Gajaran regions, has led to declining biodiversity, unsafe water quality, and health risks for communities dependent on the river.

Object learning. The article proposes a comprehensive strategy for developing hydropower resources along the Okchu River in Azerbaijan while simultaneously addressing ecological challenges. It aims to restore the river’s health by combining hydropower development with corrective ecological measures, ensuring a balance between energy production and environmental sustainability.

Methodology. The research employs historical and contemporary datasets, including water and sediment quality assessments, supported by environmental monitoring conducted by Azerbaijani and international bodies. Analytical approaches are used to measure concentrations of heavy metals – specifically copper, iron, and nickel – and to assess their ecological consequences on the river’s ecosystem and groundwater resources. In 2023, 108 water samples and 39 bottom sediment samples from the Oxchuchay River underwent 1,728 physico-chemical, 398 physico-chemical, and 3 ecotoxicological analyses. Findings revealed that iron, zinc, copper, and manganese concentrations were considerably higher than those of other metals.

Research results. Findings reveal that copper-molybdenum concentrations far exceed permissible limits, endangering drinking water safety, agricultural irrigation, and aquatic life. Monitoring at the Shayıflı station in 2023 revealed frequent exceedances of ammonium (up to 2.4 mg/L, 4.8× MPC) and manganese (up to 674 µg/L, 6.74× MPC), indicating episodic contamination. Iron levels fluctuated widely, peaking at 946 µg/L (3× MPC) in May and dropping to 37.7 µg/L in October. Hardness and sulfate remained mostly within limits but showed clear seasonal trends, linked to climatic and hydrological factors. The study highlights the declining ecological condition of the Okchu River while presenting a hydropower development plan expected to generate 120–140 million kWh annually, supplemented by an additional 70 million kWh from a new Hydropower Plant. To safeguard ecological flow, a 5.3 km purified-water pipeline to the Shayifli reservoir is proposed, along with innovative water management techniques and advanced monitoring systems.

The scientific novelty of the research. This study introduces an integrated framework that prioritizes sustainable hydropower generation alongside ecological restoration. By combining cross-border collaboration, advanced monitoring technologies, and ecological flow management, it outlines a model for balancing industrial development with the urgent need for environmental protection in transboundary river systems.