The Volga River, the largest in Europe, drains 20% of the European land area and is the source of 80% of the Caspian Sea’s freshwater inflow. Here, the river’s delta can be seen in the upper left quadrant. Water entering the sea through the delta contributes to the sediments and algal growth in the northern part of the sea. The river’s lower reaches are heavily developed with numerous unregulated releases of chemical and biological pollutants.
Although existing data are sparse and of questionable quality, there is ample evidence to suggest that the Volga is one of the principal sources of transboundary contaminants into the Caspian. The magnitude of fossil fuel extraction and transport activity constitute risks to water quality. Underwater oil and gas pipelines have been constructed or proposed, increasing potential environmental threats