utbredning, lakvattenspridning och påverkan på omgivning - Sysav

Summary
Sweden has listed fifteen goals concerning the environment, of which ”A non polluted environment”
is one. Landfills fall under this goal, since they constitute a potential burden on their surroundings. In
the beginning of the 1980’s a broad inventory of old landfills was undertaken in Sweden. The
inventory identified five objects in the municipality of Hörby in Scania, of which the Ekeboda landfill
was one. This landfill was active between 1965 and 1978, with illegal dumping continuing until the
mid 1980’s. Since the landfill was closed, the municipality of Hörby has had a number of demands
from supervising authorities concerning the Ekeboda landfill. This master’s thesis is a step in the
environmental work concerning the landfill.
The aim of this study is to delimit the extension of the landfill, its spread of leachate and its effect on
the surroundings. Further more, the aim of the study is to make one comparison between 2D- and 3D-
inversions of resistivity data and one between resistivity- and induced polarization surveys.
To fulfil the aim of the study, following geophysical surveys have been carried out: continuous
vertical electrical soundings (CVES) and following inverse modelling of resistivity and induced
polarization, as well as a magnetometrical survey without inverse modelling. Further more, auger
drilling has been carried out for geological correlation and placement of groundwater pipes for water
sampling. To characterize the water, samples were taken for chemical analysis.
The results of these surveys do not show an evident dispersion of leachate from the Ekeboda landfill.
However, the results of the resistivity survey indicate that there might be a possible leachate plume in
a westerly direction, down stream from the landfill. In general, the results of the analyses of the water
samples don’t show that they are polluted to a great extent. According to literature studies, this is what
to be expected when it comes to old landfills. Further more, the IP-survey shows that the cover of the
landfill is of inferior thickness, and occasionally completely missing, in some areas of the landfill. The
surveys also show that the cover, in some places, is of material with coarser texture than what is
recommended for a landfill cover.
The comparison between 2D- and 3D- inversions of resistivity data shows that 3D-inversions
generally give better resolution in the model. It also shows that 3D-inversions seem to be less
sensitive, compared to the 2D-inversion, towards disturbances in the ground.
The comparison between resistivity- and IP-surveys shows that IP-surveys in general are better at
delimiting the spread and the top of the landfill than resistivity surveys, especially normalised IP. The
IP-survey is also able to define the cover in a better way. Resistivity measurements are better to
distinguish between differences in materials, but IP-measurements are a good complement to resolve
ambiguities in the interpretation.
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