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Titel |
Identification of high radon areas with passive methods and geological assessments in some Italian regions |
VerfasserIn |
Marta Rossetti, Paolo Bartolomei, Massimo Esposito, Elena Marrocchino, 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 |
250041450
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Zusammenfassung |
Internationally the indoor radon exposition as health hazard is widely recognized; so in many
countries specific laws and regulations and so-called radon - risk maps have been introduced.
Few Italian Regions have started surveys for the identification of “radon prone areas”, with
independent standards and protocols and this involves a bigger uncertainty on the definition
of a national risk map failing guidelines.
In the present work a standardized methodology for indoor radon measurements has been
set up by U-Series Srl (Bologna), with attention to the development of a passive
measurement technique (solid state nuclear track detectors) on large scale. The developed
technique has been validated through an inter-laboratory comparison conducted by
the German Federal Office for Radiation Protection (BfS) in 2008 and repeated in
2009.
An indoor radon monitoring survey has been conducted in all Italian Regions with the
developed methodology and 5425 measurements have been elaborated to obtain the annual
average radon concentration in regional scale and the relapse of seasonal fluctuations on
radon concentrations were verified. For the survey, the detectors were installed in
underground rooms in workplaces and the measurements were performed over one solar year.
As a consequence of our developed methodology (measurements only in underground
rooms), indoor radon concentrations resulted generally higher than the concentrations
obtained in the National Survey; we estimated an annual mean radon concentration of 110
Bqm3 compared to 70 Bq/m3 obtained by the National Survey. Only for the Italian Regions
with the largest number of sampling (Lombardia, with the case studies of Milano
Province and Milano city, Emilia Romagna, Toscana, Puglia) the data obtained were
georeferentiated and we elaborated these data using geostatistical technique in order to
produce distribution maps of the annual average indoor radon concentration. We have
integrated the elaborated maps with the geological knowledge of the high concentration
macro-areas identified in this work in order to better determine them. This study has
allowed to point out not negligible radon concentrations also in traditionally no–risk
zone; moreover the application of the developed methodology will be useful to
give advices in order to fill Italian legislation gaps or to draft urban development
plans.
In particular, the correlation between radon concentrations and some geological features
has been proved in Lombardia and some hypothesis have been formulated to understand
the geological origin of the radon source. The high radon concentrations in the
North of the Region are related to the high uranium content in different rock types
distributed in these areas. For the flat area in correspondence of the Milan Province
and the city of Milan, traditionally considered a no-risk zone, we have done some
hypothesis of correlation between radon and the geochemical processes occurred in this
area and soil permeability and fracturation by means of the existing geological
sections.
The application of the developed methodology will be useful to give advices to fill
legislation gaps or to draft urban development plans. |
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