Caspian Sea: State of the Environment 2019

The majority of pollutant run-off into the Caspi- an Sea comes from the Volga. The contribution of the Terek River to pollutant run-off is limited to a few per cent of the total, with the exception of mineral nitrogen, for which its contribution averages 15 per cent. The concentration of pol- lutants in the Volga is slightly different to that in other rivers flowing into the Caspian Sea. The Volga is thus the main supplier of pollutants to the waters of the sea adjacent to the Russian Fed- eration, and this is due to its high water content. Sewage discharge In 2015, 15.3 km 3 of sewage was discharged into the Caspian Sea basin (Russian Federation, Fed- eral State Statistics Service 2011; Russian Federa- tion, Federal State Statistics Service 2013; Russian Federation, Federal State Statistics Service 2015). This was 15 per cent less than in 2011. Contam- inated wastewater accounted for 6.3 km 3 of the total. From 2012 to 2016, the volume of polluted sewage fell from 7.0 to 6.1 km 3 (Figure 4.6). In the Russian Caspian region, the amount of sewage discharged into water bodies (including the Caspian Sea and the rivers flowing into it) av- eraged 0.82 km 3 /year for the period 2012–2016, 0.15 km 3 (or 18 per cent) of which was contami- nated wastewater. Almost 80 per cent of wastewater generated an- nually in the Russian Caspian region in 2012– 2016 was discharged into water bodies in the Republic of Dagestan; 17.8 per cent into water bodies in Astrakhan Oblast; and 2.7 per cent into water bodies in the Republic of Kalmykia.

During the period 2012–2016, an average of 0.03 km 3 per year of polluted water was discharged into water bodies without being treated. Slightly more than half of this water was discharged into water bodies in the Republic of Kalmykia, 40 per cent into water bodies in the Republic of Dagestan,

Wastewater discharge into the Caspian Sea

Astrakhan Oblast The Republic of Dagestan The Republic of Kalmykia

Untreated polluted wastewater

Astrakhan Oblast The Republic of Dagestan The Republic of Kalmykia

Insufficiently treated wastewater

km 3

Astrakhan Oblast The Republic of Dagestan The Republic of Kalmykia

Figure 4.7: Average annual wastewater discharge, 2012–2016 Including untreated and insufficiently treated polluted wastewater, into the Caspian Sea and the rivers flowing into it from the territory of Astrakhan Oblast, the Republic of Dagestan and the Republic of Kalmykia. Source:RussianFederation,MinistryofNaturalResources2017.

Figure 4.6: Discharge of polluted sewage into the Caspian Sea basin, 2012–2016 Source: Russian Federation, Federal State Statistics Service 2017b.

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