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Titel |
Kriging analysis of geochemical data obtained by sequential extraction procedure (BCR) |
VerfasserIn |
Hana Fajkovic, Lovorka Pitarević Svedružić, Esad Prohić, Sanda Rončević, Ivan Nemet |
Konferenz |
EGU General Assembly 2015
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Medientyp |
Artikel
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Sprache |
Englisch
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Digitales Dokument |
PDF |
Erschienen |
In: GRA - Volume 17 (2015) |
Datensatznummer |
250101326
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Publikation (Nr.) |
EGU/EGU2015-444.pdf |
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Zusammenfassung |
Field examination and laboratory analysis were performed to establish whether nonsanitary
landfill Bastijunski brig has a negative influence on Vransko Lake, situated only 1500 m
away. Vransko Lake is Croatia’s largest natural lake, and it is a part of the Nature Park
and ornithological reserve, which indicates its high biodiversity. Therefore it is
necessary to understand the environmental processes and complex sediment/water
interface. Lake sediments are considered to be a good „sinkhole“and are often the
final recipients of anthropogenic and natural pollutants through adsorption onto the
organic or clay fraction in sediments. Geochemical investigation were obtained
throughout more than 50 lake sediments cores situated in different parts of the
lake
Speciation of heavy metals by modified BCR sequential extraction procedure with the
addition of a first step of sequential extraction procedure by Tessier and analysis of residual
by aqua regia were used to determine the amounts of selected elements (Al, Cd, Cr, Co, Cu,
Fe, Mn, Ni, Pb, Zn) in different fractions. With such approach it is possible to determine
which element will be extracted from sediment/soil in a different environmental conditions
and can be valuable tool for interpretation of the mobile fraction of the elements, considered
bioavailability, that present threat to biota in a case of a contaminant concentration
magnification. All sediment and soil samples were analyzed by inductively coupled plasma
atomic emission spectrometry.
More accurate interpretation of data is an advantage of BCR sequential extraction
procedure while high number of the data together with point data type could be considered as
a drawback. Due to high amount of data, graphical presentation is advisable while
interpolation tool is a first choice for point type of data, as it makes predictions for
defined area based on the measurements. Distribution maps of analysed elements
were obtained by kriging as a geostatistical method and they point out a higher
amount of mobile fraction of elements Cr, Co, Mn, Al and Fe in the NW part of the
lake. This position can be associated with the landfill. Further, mentioned analysis
and distribution maps pointed out a zone which wasn’t in a scope of investigation,
and for which is recorded higher amount of mobile fraction of elements Cd, Cu
and Zn in accordance with the other part of the lake. This zone coincides with the
estavele (“vrulja”), connected with the 7,5 km and 13,8 km distant sinkholes. Such
unexpected results signify the advantage of simultaneous use of geochemical data and
distribution maps attained by a kriging method presenting statistical distribution
of analysed parameter. In all probability, the zone with higher concentration of
pollutants can be easily concealed if distinctive distribution maps are not used. |
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