Informace o publikaci
Modern sedimentary bodies in realigned channel of the river Morava (Czech Republic): The fate of toxic contaminants
| Název česky | Recentní sedimentární tělesa v regulovaném korytě řeky Moravy (Česká republika): osud toxických kontaminantů |
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| Autoři | |
| Rok publikování | 2007 |
| Druh | Konferenční abstrakty |
| Fakulta / Pracoviště MU | |
| Citace | |
| Popis | The water course of the River Morava was realigned in the 1st half of the 20th century. Since then, the water course started to build new sedimentary bodies, depositing suspended-load and bed-load sediments from highly industrialized watersheds. The deposits contain toxic heavy metals and organic compounds bound to fine-grained solid particles. Much of this contamination is likely to be redistributed, constituting potential serious environmental hazards. A new project has been currently launched to unravel the depositional/erosional history of the modern sediment bodies and the fate of toxic compounds along the water course. Several air-borne-photography map sheets, supported by bathymetry data obtained from StreamPro river surveying and sonar measurements indicate the presence of longitudinal bars and point bars up to 260m long, 25-m wide 2.5m high. Stream-velocity measurements during low water yielded mean vertical velocities of 0.05 to 0.3 m.s-1 above the bars, and 0.1 to 0.7 m.s-1 above thalweg. The sampled bar sediments consist of light-coloured, sometimes parallel-laminated silts and sandy silts (silt fraction: 56.3 to 66.5%; sand: 20.6 to 33.9%; clay: 8.2 to 12.4%) and silty sands (sand: 55.1; silt: 37.6%, clay: 6.8%) alternating with dark silty layers enriched in organic matter. The sand fraction consists mainly of plant remains, quartz, sandstone clasts and anthropogenic materials. Above the main tributary from the highly-industrialized Zlín area, sediments of the bars contain only moderate toxic contamination (Pb: 23.9 to 24.3; Cu: 35.7 to 36.7; Cr: 38.1 to 40.4; Zn: 148.3 to 155.3 microgram.g-1; Suma PAH: 18.7 to 19.0 microgram.g-1; Suma PCB: 12.6 to 21.9 ng.g-1). Below the tributary, a significant input of toxic contamination was detected (Pb: 47.1; Cu: 66.1; Cr: 239.2; Zn: 303.7 microgram.g-1; Suma PAH: 46.3 microgram.g-1; Suma PCB: 57.3 ng.g-1), but the concentrations decrease to values comparable to- or even lower than those above the tributary, over the distance of 23.1 km along the water course. This decrease is considered to occur due to storage of the contaminants in the sediment bodies. |
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