An assessment of metal contamination in coastal sediments of the Caspian Sea.
An assessment of marine pollution due to metals was made in the Caspian Sea based on coastal sediment collected in Azerbaijan, Iran, Kazakhstan, Russia and Turkmenistan. Despite the high carbonate content, the distribution of most metals was largely controlled by terrigenous inputs. Several metals (As, Cr, Ni) exhibited concentrations that exceed sediment quality guidelines. Such metals have a high natural background but anthropogenic activities, notably mining, may further enhance concentrations. This would explain hot spots for Cu and Zn in Azerbaijan and Iran, and Cr at the mouth of the Ural River in Kazakhstan. Contamination by Hg was observed to the south of Baku Bay, Azerbaijan. Some anomalously high concentrations of Ba in the central Caspian are probably from offshore drilling operations, but the elevated U concentrations (up to 11.1 microg g(-1)) may be natural in origin. Several metals (Ag, Cd, Pb) have relatively low levels that pose no environmental concerns.
de Mora
Stephen
S
Marine Environment Laboratory, International Atomic Energy Agency, 4 quai Antoine 1er, B.P. 800, MC 98012, Monaco. s.de_mora@iaea.org
Sheikholeslami
Mohammad Reza
MR
Wyse
Eric
E
Azemard
Sabine
S
Cassi
Roberto
R
D001382:Azerbaijan; D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000737:chemistry*; D007492:Iran; D007623:Kazakhstan; D019216:Metals, Heavy / Q000032:analysis*; D012426:Russia; D014423:Turkmenistan
D019216:Metals, Heavy