Heavy metals in sediments
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 µg/g nearly three times, with values of 22.6 µg/g in Azerbaijan, 20.1 µg/g in Iran, and 20.2 µg/g in Kazakhstan. 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 µg/g standard values in several locations in Azerbaijan and Iran. A copper hot spot was also evident in Kazakhstan. This pattern of contaminant 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 µg/g), particularly south of Baku Bay where levels exceeded the NOAA standard of 0.15 µg/g. Nickel (Ni) was observed in high concentrations and exceeded the NOAA value of 21 µg/g in all the countries of the Caspian Sea, particularly in Azerbaijan and Iran where all monitored sites exceeded the standard level. The highest concentrations were found near the mouth of the Kura River, and it is clear that the Ural River also has an impact on concentration levels.
Year: 2013
From collection: Caspian Sea - State of Environment 2011
Cartographer: GRID-Arendal