Geochemical behaviour of major and trace elements in suspended particulate material of the Irtysh river, the main tributary of the Ob river, Siberia

• Published in: Applied Geochemistry
• Main Authors: Gordeev, V. V., Rachold, Volker, Vlasova, I. E.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2004
• Subjects: ob river; Siberia
• Online Access: https://oceanrep.geomar.de/id/eprint/27276/; https://oceanrep.geomar.de/id/eprint/27276/1/2004_Gordeev-Rachold-Vlasova-Geochemical_AppGeoch-19.pdf; https://doi.org/10.1016/j.apgeochem.2003.08.004

In July 2001, samples of surface suspended particulate material (SPM) of the Irtysh river in its middle and lower reaches (from Omsk City to the confluence with the Ob river) and its main tributaries were collected (18 stations along 1834 km). The SPM samples were analyzed for major and trace element composition. The results show that the geochemistry of Irtysh river SPM is related to landscape and geochemical peculiarities of the river basin on one hand and to industrial activities within the drainage area on the other hand. In the upper basin polymetallic and cinnabar deposits and phosphorite deposits with high As content are widespread. The open-cut mining and developed oil-refining, power plants and other industries lead to the contamination of the environment by heavy metals and other contaminants. The territory of the West Siberian lowland, especially the Ob-Irtysh interfluve, is characterized by the occurrence of swamps and peat-bogs. Tributaries of the Irtysh river originating in this region, have a brown color and the chemical composition of the SPM is specific for stagnant water. In the first 500–700 km downstream from Omsk City the Irtysh river has the typical Al–Si-rich suspended matter composition. After the inflow of the tributaries with brown water the SPM composition is significantly changed: an increase of POC, Fe, P, Ca, Sr, Ba and As concentrations and a strong decrease of the lithogenic elements Al, Mg, K, Na, Ti, Zr can be observed. The data show that Fe-organic components (Fe-humic amorphous compounds, which contribute ca. 75–85% to the total Fe) play a very important role in SPM of the tributaries with brown water and in the Irtysh river in its lower reaches. Among the trace metals significant enrichments relative to the average for global river SPM could only be observed for As and Cd (coefficient of enrichment up to 16 for As and 3–3.5 for Cd). It can be shown that the enrichment of As in the SPM is related to natural processes, i.e. the weathering of phosphate containing deposits with ...