Risk elements and Hg mobility in stream sediments of the Bílina River

0506666 - ÚSMH 2020 CZ eng D - Dizertace
Vöröš, Dominik
Risk elements and Hg mobility in stream sediments of the Bílina River.
Ústav struktury a mechaniky hornin AV ČR, v. v. i. Obhájeno: Ústav geologických věd, PřF MUNI, Brno. 05.06.2019. - Brno: Masarykova Univerzita, Přírodovědecká fakulta, Ústav geologických věd, 2019. 85 s.
Institucionální podpora: RVO:67985891
Klíčová slova: River Bílina * stream sediments * coals seam * risk elements * mercury mobility
Obor OECD: Geology

Expansion of the mining and chemical industries in northern Bohemia (Czech Republic) has affected the morphology of the landscape, including changes caused by deflection of the original flow of the Bílina River, which is a significant tributary of the Elbe River. In terms of assessing water quality, considerable attention has been paid to organic pollution, and numerous industrial accidents have, to a large extent, contributed to pollution of water and river sediments by persistent organic compounds (POPs). However, although water quality has improved in the river, some organic substances tend to concentrate in sediments. In the past, only marginal attention has been paid to inorganic pollution. In the environment, risk elements are released due to weathering of surrounding rocks, coal or anthropogenic sources. For a comprehensive assessment of the level of pollution, the elemental composition of natural resources has been defined as essential.
This thesis presents the results of elemental analyses, especially those of risk, e.g. V, As, Pb, Hg in stream sediments; and surrounding rocks including coal. The levels of these elements were determined using various analytical methods (XRF, ICP-MS, AAS). Coal samples were subjected to chemical and technological analyses, including huminite reflectance, to clarify the degree of coalification. Geochemical conditions in sediments are reflected by the present forms of the elements. To determine these conditions, samples of stream sediments from Záluží-Ohníč stretch and coal were subjected to thermal desorption to determine forms of Hg.
This work contributed to the view that the increased levels of risk elements are caused by surrounding coal waste dumps in the Záluží-Ohníč stretch, which are washed downstream into the river system. This interpretation is supported by the occurrence of coal and residues of incomplete combustion in river sediments. Thermal desorption results indicate that Hg is bound in the form of stable sulphides under natural conditions, thereby not posing a threat to the environment.
Trvalý link: http://hdl.handle.net/11104/0297868