2007
Record of river contamination in modern oxbow lake deposits (Czech Republic): Depositional architecture and sediment contamination
BÁBEK, Ondřej, Klára HILSCHEROVÁ, Slavomír NEHYBA, Josef ZEMAN, Martin FAMĚRA et. al.Základní údaje
Originální název
Record of river contamination in modern oxbow lake deposits (Czech Republic): Depositional architecture and sediment contamination
Název česky
Záznam říční kontaminace v sedimentech recentního mrtvého ramene (Česká republika): depoziční architektura a kontaminace sedimentů
Autoři
BÁBEK, Ondřej (203 Česká republika, garant, domácí), Klára HILSCHEROVÁ (203 Česká republika, domácí), Slavomír NEHYBA (203 Česká republika, domácí), Josef ZEMAN (203 Česká republika, domácí), Martin FAMĚRA (203 Česká republika, domácí) a Juraj FRANCŮ (203 Česká republika, domácí)
Vydání
25th IAS Meeting of Sedimentology 2007, Patras - Greece, Book of Abstracts, 2007
Další údaje
Jazyk
angličtina
Typ výsledku
Konferenční abstrakt
Obor
10500 1.5. Earth and related environmental sciences
Stát vydavatele
Řecko
Utajení
není předmětem státního či obchodního tajemství
Kód RIV
RIV/00216224:14310/07:00022557
Organizační jednotka
Přírodovědecká fakulta
Klíčová slova anglicky
fluvial sediments; ground panatration radar; cesium dating; heavy metals; persistent organic pollutants
Štítky
Příznaky
Mezinárodní význam, Recenzováno
Změněno: 29. 4. 2011 12:56, prof. RNDr. Luděk Bláha, Ph.D.
V originále
Most of the toxic compounds transported by rivers are 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. Stratigraphic record of sediment contamination is usually incomplete in the highly dynamic systems such as river channels but it can be more complete in floodplains or oxbow lakes. We studied sediments and stratigraphic architecture of an artificial oxbow lake, a former meander separated by river realignment in 1930s. The lake has been connected to the active channel via a water-gate allowing contaminated fine-grained sediments to enter and settle in the lake. Facies analysis of four cores up to 4m long, supported by ground penetration radar (GPR) profiling allowed us to recognise two major depositional phases. The basal fluvial succession (more than 255 cm depth) is composed of light-grey, parallel-laminated, occasionally graded or cross-laminated silts and sandy silts (sand fraction: 8.5 to 30.0 %; silt: 65.4 % to 84.6 %; clay: 4.6 to 6.8 %). In GPR sections, this succession consists of several convex-upward bodies composed of lateral and vertical accretion units. The upper, oxbow-lake succession (0 to 255 cm depths) is composed of horizontally stratified layers of light-coloured silts alternating with dark-coloured silts and sandy silts (sand fraction: 8.4 to 20.1 %; silt: 76.4 to 86.9 %; clay: 3.5 to 6.3 %) rich in organic matter and plant remains. In GPR sections, this succession consists of horizontal reflectors that seal the hummocky upper surface of the underlying succession. Dating of the lake deposits based on the Chernobyl 137Cs anomaly, and the historical records of river realignment indicate relatively high sedimentation rates of ~4 to ~5 cm per year. Contamination in the oxbow lake deposits (Pb: 25.5 to 54.5; As: 8 to 17.3; Cd: 0.6 to 4.8; Suma PAH(16): 6.7 to 29.0 microgram/g; Suma PCB(7): 11.1 to 24.8 ng/g) is much higher than in the underlying fluvial deposits (Pb: 14 to 17.4; As: 5.6 to 7.1; Cd: 0.1 to 0.2; Suma PAH(16): 0.07 to 0.4 microgram/kg; Suma PCB(7): 0.7 to 2.6 ng/g), reaching its maximum approximately 25 to 30 years ago. For the last ~25 years, the contents of toxic organic compounds and heavy metals in the oxbow-lake sediments have decreased by the factor of 2 to 2.5. Unravelling the stratigraphy of the oxbow-lake deposits seems to have great potential in making estimates of the total contamination being transported by rivers, its history and distribution.
Česky
Most of the toxic compounds transported by rivers are 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. Stratigraphic record of sediment contamination is usually incomplete in the highly dynamic systems such as river channels but it can be more complete in floodplains or oxbow lakes. We studied sediments and stratigraphic architecture of an artificial oxbow lake, a former meander separated by river realignment in 1930s. The lake has been connected to the active channel via a water-gate allowing contaminated fine-grained sediments to enter and settle in the lake. Facies analysis of four cores up to 4m long, supported by ground penetration radar (GPR) profiling allowed us to recognise two major depositional phases. The basal fluvial succession (more than 255 cm depth) is composed of light-grey, parallel-laminated, occasionally graded or cross-laminated silts and sandy silts (sand fraction: 8.5 to 30.0 %; silt: 65.4 % to 84.6 %; clay: 4.6 to 6.8 %). In GPR sections, this succession consists of several convex-upward bodies composed of lateral and vertical accretion units. The upper, oxbow-lake succession (0 to 255 cm depths) is composed of horizontally stratified layers of light-coloured silts alternating with dark-coloured silts and sandy silts (sand fraction: 8.4 to 20.1 %; silt: 76.4 to 86.9 %; clay: 3.5 to 6.3 %) rich in organic matter and plant remains. In GPR sections, this succession consists of horizontal reflectors that seal the hummocky upper surface of the underlying succession. Dating of the lake deposits based on the Chernobyl 137Cs anomaly, and the historical records of river realignment indicate relatively high sedimentation rates of ~4 to ~5 cm per year. Contamination in the oxbow lake deposits (Pb: 25.5 to 54.5; As: 8 to 17.3; Cd: 0.6 to 4.8; Suma PAH(16): 6.7 to 29.0 microgram/g; Suma PCB(7): 11.1 to 24.8 ng/g) is much higher than in the underlying fluvial deposits (Pb: 14 to 17.4; As: 5.6 to 7.1; Cd: 0.1 to 0.2; Suma PAH(16): 0.07 to 0.4 microgram/kg; Suma PCB(7): 0.7 to 2.6 ng/g), reaching its maximum approximately 25 to 30 years ago. For the last ~25 years, the contents of toxic organic compounds and heavy metals in the oxbow-lake sediments have decreased by the factor of 2 to 2.5. Unravelling the stratigraphy of the oxbow-lake deposits seems to have great potential in making estimates of the total contamination being transported by rivers, its history and distribution.
Návaznosti
| MSM0021622412, záměr |
|