Bioavailability, mobility, and origination of metals in sediments from Anzali Wetland, Caspian Sea

• Published in: Marine pollution bulletin 2018-11, Vol.136, p.22-32
• Main Authors: Bastami, Kazem Darvish, Neyestani, Mahmoud Reza, Molamohyedin, Neda, Shafeian, Elnaz, Haghparast, Sara, Shirzadi, Imam Ali, Baniamam, Mehrnaz
• Format: Article
• Language: English
• Subjects: Anzali wetland; Bioavailability; Biological Availability; Cadmium; Carbonates; Caspian Sea; Chemical speciation; Chromium; Enrichment; Environmental Monitoring - methods; Factor analysis; Geologic Sediments - chemistry; Heavy metals; Iran; Lead; Marine pollution; Metal; Metals; Metals, Heavy - analysis; Mobility; Nickel; Organic chemistry; Oxidation; Pollutant load; Pollution index; Pollution load; Risk Assessment; Sediment; Sediments; Speciation; Stations; Water Pollutants, Chemical - analysis; Wetlands; Zinc
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/j.marpolbul.2018.08.059

We investigated the bioavailability, mobility, and origin of heavy metals present in sediments from the Anzali Wetland. Chemical speciation of the metals was performed according to the Tessier method. Results indicated that Cd and As showed the highest level of bioavailability, whereas Cr showed the lowest level. Cr, Co, and V were shown to have a terrestrial origin. The metal As was mostly found in the reducible fraction (F3), whereas other metals were highest in the residual phase. The levels of Co present in the oxidizable fraction (F4); Pb and Cd present in the carbonate fraction (F2); and the other metals present in the exchangeable fraction (F1) were found to be the lowest. On the basis of the Risk Assessment Code of metals, Cd at most stations, As and Ni at some stations, and Zn at one station revealed to have a moderate risk. Co and Pb were found to have a low risk at all stations. Considering Pollution Load Index, stations 2 and 3 were classified as moderately polluted and the remaining stations were unpolluted. As suggested by enrichment factor analysis, As was moderately enriched and other metals had a deficiency to minimal enrichment at all the stations. •Geochemical fraction of metals was determined in surface sediments from the Anzali wetland.•Cr, Co, and V were terrestrially originated.•Cd and As had the highest level of bioavailability.