Caspian Sea: State of the Environment 2019

360 km 3

thousand tonnes

200

River water run-off (km 3 )

Annual discharge of Petroleum Hydrocarbons (thousand tons)

150

270

100

180

90

50

0

0

1980

1985

1990

1995

2000

2005

2010

2015

1977

Figure 4.3: Fluctuations in Volga River water run-off (km 3 ) and discharge of oil products (thousand tons), 1977–2016 Source: Alexeevsky et al. 1997.

tons per year in 1991–2000 and 18,600 tons per year in 2001–2010, fluctuating around 18,200 tons per year for the following five years. A significant reduction in the discharge of oil products (as well as organochlorine pesticides) into the Caspian Sea with water from the Volga was highlighted in a 2007 report published by the Federal Service for Hydrometeorology and En- vironmental Monitoring (Roshydromet): Trends and Dynamics of Environmental Pollution in the Russian Federation at the Turn of the Twenty-First Century (Table 4.1). Pollutant run-off has stabi- lized during the second decade of this century.

here and subsequently to the part of the basin which is located within the Russian Federation) accounts for almost half (approximately 45 per cent) of all wastewater discharge into seas in the Russian Federation. Since 1993, when statistical reports were first produced, the amount of dis- charge has halved, from 12.1 to 6.1 km 3 . As discharge of polluted wastewater into the Cas- pian Sea basin decreased, the flow of pollutants di- rectly into the sea with river water also decreased. An example of this is the decline in the discharge of oil products from the Volga River, which aver- aged 91,300 tons per year in 1981–1990, 66,600

Fe

mineral nitrogen inorganic phosphorus total phosphorus dissolved silicium phosphorus

Petroleum Hydrocarbons

Zn Ni Mn Cu Phenols Pb Others

Figure 4.4: Total chemical run-off from the Volga and Terek rivers (thousand tons per year), 2012–2016

46