Regional Contamination of Moravia (South-Eastern Czech Republic): Temporal Shift of Pb and Zn Loading in Fluvial Sediments

Bábek

et al. 2013

E3S Web of Conferences

Abstract. Regional contamination of southern Moravia (SE part of the Czech Republic) by heavy metals and magnetic particles during the 20th century was quantified in fluvial sediments of the Morava River. The influence of local sources to the regional contamination of the river sediments and impact of sampling sites heterogeneity were studied in profiles with different sedimentology (facies) and lithology. For this purpose, hundreds of samples were obtained from regulated channel banks and naturally inundated floodplains and proxy elementary analyses have been carried out by X-ray fluorescence spectroscopy (ED XRF), further calibrated by ICP MS. Magnetic susceptibility as a proxy of industrial contamination was determined and the age model has been obtained by 210 Pb dating method. After establishing the lithological background from floodplain profiles, assessment of heavy metal contamination was done by using enrichment factors (EFs) of heavy metals (Pb, Zn, Cu, Cr) and magnetic susceptibility. Floodplain sedimentary profiles were found to be realiable for assessment of contamination and reconstruction of large scale, i.e. a really averaged regional contamination, while regulated channel banks are suitable for obtaining of more or less qualitative information of influence of local point sources in the area because sediments from regulated river banks qualitatively reflect the actual local contamination of the river system. It allowed us to distinguish the influence of local sources of contamination by comparing with more spatially averaged contamination signal from more distal floodplain profiles. The study area is rather weakly contaminated (EF ~ 1-2), while individual sediment strata from regulated channel banks contains several times larger concentrations of heavy metals.

Section: Resuts and Discussionmentioning

confidence: 99%

Human impact on fluvial sediments: how to distinguish regional and local sources of heavy metals contamination

Nováková

Bábek

et al. 2013

E3S Web of Conferences

“…Since the turn of the 19th and 20th century, local industrial enterprises, regional metallurgy and coal combustion [33] have caused diffuse pollution of the waste areas in the Czech Republic [11,34], including the Ploučnice floodplain [4,35]. Local industries in Panenský Creek, a right-side tributary of the Ploučnice River, have caused lead (Pb) and zinc (Zn) pollution [19,36].…”

Section: Pollution History Of the Ploučnice River And Its Floodplainmentioning

confidence: 99%

Threat of Pollution Hotspots Reworking in River Systems: Case Study of the Ploučnice River (Czech Republic)

Elznicová

Popelka

et al. 2019

IJGI

Self Cite

As fluvial pollution may endanger the quality of water and solids transported by rivers, mapping and evaluation of historically polluted fluvial sediments is an urgent topic. The Ploučnice River and its floodplain were polluted by local uranium mining from 1971–1989. We have studied this river since 2013 using a combination of diverse methods, including geoinformatics, to identify pollution hotspots in floodplains and to evaluate the potential for future reworking. Archival information on pollution history and past flooding was collected to understand floodplain dynamics and pollution heterogeneity. Subsequently, a digital terrain model based on laser scanning data and data analysis were used to identify the sites with river channel shifts. Finally, non-invasive geochemical mapping was employed, using portable X-ray fluorescence and gamma spectrometers. The resulting datasets were processed with geostatistical tools. One of the main outputs of the study was a detailed map of pollution distribution in the floodplain. The results showed a relationship between polluted sediment deposition, past channel shifts and floodplain development. We found that increased concentration of pollution occurred mainly in the cut-off meanders and lateral channel deposits from the mining period, the latter in danger of reworking (reconnecting to the river) in the coming decades.

“…The sedimentary environment is much less variable in reservoirs than in floodplains and has much less reworking in deep, quiet locations. Their permanent existence under the water column, which decreases post-depositional migration, may provide more detailed reconstruction of historical pollution (Matys Grygar et al 2012 ). Seismic profiles (Palanques et al 2014 ) and other geophysical techniques (Bábek et al 2008 ) are efficient in distinguishing reservoir sediments from pre-dam deposits.…”

Section: Storage Of Heavy Metals In Dam Reservoirsmentioning

confidence: 99%

A Review of Flood-Related Storage and Remobilization of Heavy Metal Pollutants in River Systems

Ciszewski

2016

Water Air Soil Pollut

168

Recently observed rapid climate changes have focused the attention of researchers and river managers on the possible effects of increased flooding frequency on the mobilization and redistribution of historical pollutants within some river systems. This text summarizes regularities in the flood-related transport, channel-to-floodplain transfer, and storage and remobilization of heavy metals, which are the most persistent environmental pollutants in river systems. Metal-dispersal processes are essentially much more variable in alluvia than in soils of non-inundated areas due to the effects of flood-sediment sorting and the mixing of pollutants with grains of different origins in a catchment, resulting in changes of one to two orders of magnitude in metal content over distances of centimetres. Furthermore, metal remobilization can be more intensive in alluvia than in soils as a result of bank erosion, prolonged floodplain inundation associated with reducing conditions alternating with oxygen-driven processes of dry periods and frequent water-table fluctuations, which affect the distribution of metals at low-lying strata. Moreover, metal storage and remobilization are controlled by river channelization, but their influence depends on the period and extent of the engineering works. Generally, artificial structures such as groynes, dams or cut-off channels performed before pollution periods favour the entrapment of polluted sediments, whereas the floodplains of lined river channels that adjust to new, post-channelization hydraulic conditions become a permanent sink for fine polluted sediments, which accumulate solely during overbank flows. Metal mobilization in such floodplains takes place only by slow leaching, and their sediments, which accrete at a moderate rate, are the best archives of the catchment pollution with heavy metals.