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Titel |
High Radon concentration in the karst area of south Puglia, Italy |
VerfasserIn |
Mattia Taroni, Paolo Bartolomei, Massimo Esposito, Carmela Vaccaro |
Konferenz |
EGU General Assembly 2010
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Medientyp |
Artikel
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Sprache |
Englisch
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Digitales Dokument |
PDF |
Erschienen |
In: GRA - Volume 12 (2010) |
Datensatznummer |
250041449
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Zusammenfassung |
The Radon mapping are normally based on regular grids or on geological maps. The
geological maps are advantageous because foresee little areas with high hazard in zones
which are otherwise considered like a low risk.
The Italian national maps consider the South Puglia, Lecce Karst, as a zone with low risk,
but this region presents local important anomalies that can be seen with the geological Radon
map.
The methodology used to understand the natural phenomena (that are the basis of the
analysis of potential Radon risk) is based on a preliminary study from literature:
Geological study, general classification, environment formation in which it has
developed the area or part of it, detailed studies of the area investigated, the
underground structure, level of fracturing, cracking, and primary and secondary
porosity, seismic of area.
The Area’s identification with different risk degrees of Radon production,
concentration and emanation characterized by natural boundaries, geological,
geomorphological, etc...
Information obtained from paragraphs 1 and 2 provide the "Indices of potential risk of the
generation, emanation and diffusion of Radon”; this hazard indices allow to optimize the
measurements distribution in soils. We Identify the sub-areas of the zone study that can be
characterized by high Radon concentrations, dividing these by "natural" hypothetical lines
such as the lithology changing, permeability, subsoil structure, etc. ... The preliminary study
allows the optimisation of sampling strategy based on not Uniform distribution of “in situ”
measures, where to intensive the measures and where to make only control points of Radon
concentration.
With these information and with Uranium concentration in samples of different
geological formations and Radon measures in water and in soil air we obtained thematic
maps and box-plots linking the natural geological indices and we identified the factors that
govern the Radon rise and diffusion.
The Lecce Karst’s study have foreseen:
Samples of rocks and soils to determine the Uranium concentration;
Collection of water samples for the determination of Radon concentrations;
Measurements of the Radon concentration in soil air;
The Lecce’s area is divided into 4 sub-areas, each of them with the same geological
features: subsoil structure with high/normal/low fracturing, cracking, permeability, porosity,
ecc-¦
The potential Radon risk increases with the alteration’s degree of subsoil structure.
Results show that the 4 Lecce’s subareas are characterized by average Radon value
between 1.000-2.000 Bq/m3, and that in 2 of the 4 zones, characterized by high
fracturing and big permeability, the range is high, from 400 Bq/m3 to over the 60.000
Bq/m3.
The distribution of anomalies isn’t homogeneous in the study zone, but as Hot-Spot and
these are present in all sub-areas; the greatest number is detected in areas with
high fracturing and cracking and in areas with lithological changes at different
permeability.
The others determinants factors in these areas are those anthropogenic; in some little
zones belonging to subareas there are industrial and commercial areas built removing soil and
damaging and altering the subsoil structure; in this way create zones of Radon
accumulation in the soil air with fast ascent of the gas to the surface, and this produce
high Radon concentration indoor. In the soil around these areas, few meters from
buildings, and in the indoor air the Radon concentration is higher than 60.000 Bq/m3. |
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