Caspian Sea 2011


Metals According to the first monitoring programme, 23 metals were found in Caspian Sea sediments. Some of the most significant results show: Arsenic (As) concentrations were fairly high in the region and, in some areas, exceeded the NOAA standard value of 8.2 µ g/g nearly three times, with values of 22.6 µ g/g in Azerbaijan, 20.1 µ g/g in Iran, and 20.2 µ g/g in Kazakhstan. Barium was detected at very high levels in several central Caspian Sea regions, with the highest concentration of 1250 µ g/g in Kazakhstan. Barium (Ba) is used in mud drilling, and these high levels may be the result of this ac- tivity. However, this is not an element of concern with respect to environmental toxicity. Chromium (Cr) concentrations exceeded the NOAA value of 81 µ g/g at almost all the locations in Azerbaijan and Iran, and at some sites in Kazakhstan. The Caspian Sea region is mineral-rich and several countries, most notably Kazakhstan, are impor- tant producers of chromium. The high concen- trations of Cr stem from its natural presence in the region. Copper (Cu) dispersion in sediments was considerably lower in the North Caspian Sea, compared to those found in the Sea’s central and southern areas. Copper concentrations surpassed the NOAA 34 µ g/g standard values in several loca- tions in Azerbaijan and Iran. A copper hot spot was also evident in Kazakhstan. This pattern of con- taminant presence might indicate that the Kura River is the main source of Cu, and contamination likely caused by mining or agricultural activities in the catchment area. Mercury (Hg) concentration levels were quite high at some sites in Azerbaijan (0.450 µ g/g), particularly south of Baku Bay where levels exceeded the NOAA standard of 0.15 µ g/g. Nickel (Ni) was observed in high concentrations and exceeded the NOAA value of 21 µ g/g in all the countries of the Caspian Sea, particularly in Azerbaijan and Iran where all monitored sites ex- ceeded the standard level. The highest concen- trations were found near the mouth of the Kura River, and it is clear that the Ural River also has an impact on concentration levels. These generally high levels reflect a predominantly natural nickel presence, but this could be augmented by mining activities. There have been claims of significantly

higher concentrations of certain naturally occur- ring radionuclides, especially uranium (U), in the Caspian Sea. The highest concentrations of ura- nium (11.1 µ g/g) were identified in the Kazakhstan coastal sector: this could be due to the uranium enrichment plant in Aktau, Kazakhstan. Zinc (Zn) concentrations were relatively high in Iran where concentrations exceeded the ISQH value of 124 µ g /g (Mora and Sheikholeslami 2002). In 2005, few metal concentrations were observed in surveys, apart from a number of sites in Azer- baijan where the highest mercury values were 0.20 µ g/g, exceeding the NOAA standard value of 0.15 µ g/g-1. Though concentrations of some elements - (such as As, Cr, Cu and Ni) - surveyed were high and, in some locations, surpassed sedi- ment quality guidelines by two or three times, such metals undoubtedly have a high natural background in this mineral-rich region (IAEA 2006). An anthropogenic activity, such as mining, might also lead to more metal content in some Caspian Sea sediments: an example of this is the copper hot spot in Azerbaijan. Mercury levels in 2005 were still noticeably high at a number of sites in Azerbaijan (CEP 2007a). However, com- pared to 2001 surveys, the levels are lower. In 2009, extensive pollution levels caused by metals in Azerbaijan were not evident. Neverthe- less, arsenic concentrations were high compared to natural levels in Azerbaijan’s soil, which could be related to natural factors such as volcanic ac- tivity peculiar to the area. Nevertheless, in all cases, its concentration did not exceed the Neth- erlands recommended average safety limit of 70 mg/kg and the admissible Concentration Limit Value of 30 mg/kg. In the Shrivand sewage canal, the Kura River and Baku Bay, high rates of Cr, Cu and other metal concentrations were noted in bottom sediments (TACIS 2009b). High concen- trations of Cd were observed only in the Baku area. Bottom sediments in Kazakhstan contained relatively high concentrations of Cu, Cd, and Hg. However, these did not exceed the standards (Netherlands). Initial results in Turkmenistan showed a relatively low concentration of metals,


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