Toxic
substances
Toxic persistent and bio-accumulating substances are discharged by industry, untreated
wastewater and agriculture directly into the sea and through the river and drainage
systems. Analysis of the concentrations in the sea and sea sediments of toxic substances
is so far inadequate to provide a comprehensive description, but it is known that the
greatest concentrations are likely to be found close to major coastal industries (e.g. the
Absheron peninsular in Azerbaijan) and the mouths of rivers which have mining, chemical
industries and agriculture on their catchments.
 Routine monitoring by the responsible institutions
includes analysis of toxic substances in only some areas. Localised investigations by oil
exploration companies in Azerbaijan and Kazakhstan waters have generally found low levels
of toxic substances in the sediments. Investigations by the University of Moscow in the
Volga and Kura estuaries have not found particularly high levels of contamination, but
these investigations have not been comprehensive. Investigations around the Absheron
peninsular into the extent of mercury contamination have found high levels of
contamination in sediments off the Sumgait area.
Nutrients
Eutrophication of parts of the Caspian Sea may be a substantial risk due to high
discharges of nutrients to some coastal waters from rivers and domestic and industrial
wastewater. The biological response to high levels of nutrients can be assessed by
observing the levels of chlorophyll-a, high levels of which indicate high levels of
phytoplankton. High levels of phytoplankton may cause oxygen deficiency as dead
phytoplankton in the bottom water degrades. Existing monitoring programmes do not measure
the total loads of nitrogen or phosphorous discharged to the sea. Furthermore, no routine
measurements of chlorophyll-a are made, so it is difficult to assess eutrophication risks
in the coastal areas. There appears to be the highest risk in the shallow waters off the
Volga delta, but the risk cannot presently be quantified.
Radio-nuclides
The seawater is not routinely monitored for the presence of radio-nuclides. Nonetheless,
specific coastal industrial activities indicate that there may be in some areas health
risk from the presence of radio-nuclides in the sea and sediments, resulting from drilling
and nuclear industries.
Oils
Although oil production facilities in obviously poor condition and extensive on-land oil
pollution are some of the most visible environmental issues in the Caspian region, it is
unlikely that oil pollution of the open sea is an important issue. In local areas such as
Baku Bay there is considerable oil pollution of the water body and sediments.
Techniques used in the NIS countries for routine analysis
of oil concentrations in water and sediments are inaccurate and unreliable; they may
over-estimate concentrations by up to two orders of magnitude. An analysis of the
relevant importance of all potential sources of contamination indicates that the majority
of the total oil discharged to the sea originates from the rivers through discharges of
domestic and industrial wastes and from natural seepages and under-sea volcanoes. Recent
investigations of bed sediments in open waters by the oil industry and in the estuaries by
University of Moscow have found low concentrations of oil products. Nonetheless, there are
clearly areas where there is considerable local pollution close to the Soviet-era oil
production installations on land and in the sea.
|
