Caspian Sea 2011

State of the Environment of the Caspian Sea

Table 3. Mean values of pollutants in Dagestan coastal waters and a cross section of the middle Caspian Sea, 1978-2003 (from Korshenko and Gul, 2005).

Region

TPHs (mg/L)

NH4 (µg/L)

Phenols (mg/L)

Detergents (mg/L)

Lopatin town

0.076

110

0.006

0.056

Terek River

0.084

101

0.007

0.064

Sulak River

0.074

100

0.006

0.065

Makhachkala town

0.070

90

0.006

0.062

Kaspyisk town

0.068

86

0.005

0.060

Izberbash town

0.094

89

0.007

0.061

Derbent town

0.086

90

0.006

0.066

Samur River

0.069

90

0.006

0.058

Cross-section, Chechen-Magy- shlak Cross-section, Makhachkala- Sagunduk Average for all regions

0.063

66

0.004

0.053

0.080

62

0.005

0.043

0.076

91

0.006

0.060

an increase in dissolved organic matter, ammo- nium and urea (an organic nitrogen-containing compound). Sea level rise has further increased the amount of organic matter entering the sea from the Volga River delta and this has resulted in the formation of large areas of oxygen deple- tion that can extend to depths of 10m. This can cause algal blooms, benthic dieoffs, fish kills and changes in fish distribution (Butts and Bradshaw, 1999). In his research Sapozhnikov revealed that a considerable amount of organic matters is also accumulated in the bottom sediments where for example, nitrates are partially reduced to nitrites (Sapozhnikov at al. 2008). Seasonal variations in dissolved oxygen in the Caspian Sea adjacent to Iran, were investigated by Zaker (2007). Measurements were made along a transect perpendicular to the eastern part of the Southern Caspian coast. The results indicate that

as Transboundary Diagnostic Analyses, relevant studies on Volga, Kura-Araks and Terek rivers, recent Regional Water Quality Monitoring Plan, and recent research papers. Water chemistry The monitoring of the central and southern Cas- pian Sea between 1995 and 2007 by Sapozhnikov et al. (2005, 2006, 2007, 2008) revealed changes in the water chemistry occurring over this period. They observed similarities with changes apparent in the Black Sea between 1986-1993, that were attributed to the regulation of rivers entering the sea. In the Caspian Sea, the construction of water reservoirs on inflowing rivers changed the water chemistry and consequently the biologi- cal productivity. The construction of the resevoirs resulted in a drastic reduction in the supply of phosphates, dissolved silicic acid, and particulate phosphorus and silicon. This was accompanied by

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