Summary:
In the framework of this thesis, a radiological characterization of different types of sites in
northern Algeria namely, urban coastal (Algiers), mountainous (Chréa) and marine (Algiers
bay), were achieved. This made it possible to assess, using gamma spectrometry technique,
the levels of specific activities of some radionuclides of interest (
7 Be,
210 Pb and
137 Cs),
present in different matrices in the environment (aerosols, rainwater, particles, soils and
marine sediments). Dry and/or wet deposition move these radionuclides from the atmosphere
to the terrestrial and the marine environments.
Some additional work was devoted to determine the hydrochemistry of rainwater, the
chemical and mineralogical composition of the particles, the soils and the sediments; these
elements are essential data for the interpretation of the obtained results.
In the atmospheric compartment, the study included: (i) the assessment of temporal variations
of the radionuclides, (ii) comparison of the activity levels between the two monitored sites
(Algiers and Chréa), (iii) search for a correlation with the meteorological parameters as well
as (iv) the determination of the origin of the atmospheric air masses transporting radioactivity
through the use of the HYSPLIT software.
Sediments from Algiers bay were dated using a new methodology based on piecewise
classical models. A radioecological evaluation using the ERICA software as well as the
history of the chemical contamination in this bay were studied.
In the terrestrial environment, the
137 Cs level has been studied with respect to the altitude. Its
concentration in Bq / kg as a function of the core depth shows an exponential decrease up to
the layer of 21 cm. The results show also that the specific activities in the surface layers are
higher than those of the national radiological reference level. The RESRAD–Biota and
RESRAD–On site codes allowed one to carry out a radioecological and dosimetric assessment
of Chréa’s site.
Keywords:
137 Cs,
210 Pb,
7 Be, Gamma spectrometry, North of Algeria, Radioecology,
environmental matrices, dating, HYSPLIT, RESRAD, ERICA codes
In the framework of this thesis, a radiological characterization of different types of sites in
northern Algeria namely, urban coastal (Algiers), mountainous (Chréa) and marine (Algiers
bay), were achieved. This made it possible to assess, using gamma spectrometry technique,
the levels of specific activities of some radionuclides of interest (
7 Be,
210 Pb and
137 Cs),
present in different matrices in the environment (aerosols, rainwater, particles, soils and
marine sediments). Dry and/or wet deposition move these radionuclides from the atmosphere
to the terrestrial and the marine environments.
Some additional work was devoted to determine the hydrochemistry of rainwater, the
chemical and mineralogical composition of the particles, the soils and the sediments; these
elements are essential data for the interpretation of the obtained results.
In the atmospheric compartment, the study included: (i) the assessment of temporal variations
of the radionuclides, (ii) comparison of the activity levels between the two monitored sites
(Algiers and Chréa), (iii) search for a correlation with the meteorological parameters as well
as (iv) the determination of the origin of the atmospheric air masses transporting radioactivity
through the use of the HYSPLIT software.
Sediments from Algiers bay were dated using a new methodology based on piecewise
classical models. A radioecological evaluation using the ERICA software as well as the
history of the chemical contamination in this bay were studied.
In the terrestrial environment, the
137 Cs level has been studied with respect to the altitude. Its
concentration in Bq / kg as a function of the core depth shows an exponential decrease up to
the layer of 21 cm. The results show also that the specific activities in the surface layers are
higher than those of the national radiological reference level. The RESRAD–Biota and
RESRAD–On site codes allowed one to carry out a radioecological and dosimetric assessment
of Chréa’s site.
Keywords:
137 Cs,
210 Pb,
7 Be, Gamma spectrometry, North of Algeria, Radioecology,
environmental matrices, dating, HYSPLIT, RESRAD, ERICA codes