Detailed Information on Publication Record
2009
Flood deposits in a modern oxbow lake (Czech Republic): Sedimentary archive of 25-year old river contamination
BÁBEK, Ondřej, Petr DOBROVOLNÝ, Martin FAMĚRA, Klára HILSCHEROVÁ, Jiří KALVODA et. al.Basic information
Original name
Flood deposits in a modern oxbow lake (Czech Republic): Sedimentary archive of 25-year old river contamination
Name in Czech
Povodňové sedimenty v moderním mrtvém rameně (Česká republika): sedimentární archív kontaminace řeky za posledních 25 let
Authors
BÁBEK, Ondřej (203 Czech Republic, guarantor, belonging to the institution), Petr DOBROVOLNÝ (203 Czech Republic, belonging to the institution), Martin FAMĚRA (203 Czech Republic, belonging to the institution), Klára HILSCHEROVÁ (203 Czech Republic, belonging to the institution), Jiří KALVODA (203 Czech Republic, belonging to the institution) and Jan SEDLÁČEK (203 Czech Republic)
Edition
27th Meeting of IAS 2009, Alghero Italy, Book of Abstracts, 2009
Other information
Language
English
Type of outcome
Konferenční abstrakt
Field of Study
10500 1.5. Earth and related environmental sciences
Country of publisher
Czech Republic
Confidentiality degree
není předmětem státního či obchodního tajemství
RIV identification code
RIV/00216224:14310/09:00036718
Organization unit
Faculty of Science
ISBN
978-88-6025-123-7
Keywords in English
heavy metals; flood deposits; high-resolution stratigraphy; sediment accumulation rates; contamination
Tags
International impact
Změněno: 29/4/2011 12:54, prof. RNDr. Luděk Bláha, Ph.D.
V originále
Toxic compounds transported by rivers are usually bound to fine-grained solid particles, which are deposited as contaminated fluvial sediments. Much of this contamination is likely to be redistributed, constituting potential serious environmental hazards. Relatively complete sediment archives of river contamination can be found in floodplains and oxbow lakes. We analysed a high-resolution (month- to seasonal scale) stratigraphic record of heavy metal contamination in deposits of an artificial oxbow lake, a former meander of River Morava, a left hand tributary to River Danube. Since 1930s, the lake has been connected to the river channel via a water gate allowing contaminated fine-grained sediments to enter and settle in the lake. The accumulated sediment forms a distinct wedge, about 150 m long, 30 m wide and >2.5 m thick in the proximal part. 137Cs dating revealed a distinct (~300 Bq.kg-1) Chernobyl anomaly at ~130 cm depth, implying relatively high sedimentation rates of ~5.9 cm per year. Three cores were drilled in the proximal-distal direction of the wedge, and correlated using magnetic susceptibility logs and ground-penetration radar sections. Greyscale colour image analysis of X-ray images of two of the cores allowed further enhancement of the correlation on a cm-scale. The X-ray images revealed numerous sand-silt laminae 0.5 to 4 cm thick, which are correlatable over ~100m distance along the sediment wedge. Time distribution of the laminae was estimated from the average sedimentation rate and correlated with time series of monthly river discharge for the last 27 years. The thickest laminae roughly correlate with major flood events. Concentrations of most heavy metals (V, Cr, Co, Ni, Cu, Zn, As, Mo, Cd, Sb, Pb, Hg) show a long-term decreasing trends. These trends are, however, punctuated by high-amplitude, short-term variations, which is related to sediment grain size. While the sand-silt flood layers are depleted in heavy metals, the fine-grained laminae show the highest values of heavy-metal concentrations. We conclude, that the distribution of pollutants in sedimentary archives is dependent on delicate grain-size variations, which may obscure the long-term trends.
In Czech
viz anglický abstrakt
Links
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