Occupational Intakes of Radionuclides Part 1 - ICRP

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DRAFT REPORT FOR CONSULTATION
AI2 long-term retention (t½ about 700 d) of a fraction, taken to be 0.6, of
the deposit in the alveolar-interstitial region.
AI3 very long-term retention (t½ about 6000 d) of a fraction, taken to be
0.1, of the deposit in the alveolar-interstitial region.
BB1 short-term retention (t½ about 100 minutes) of particles in the
bronchial region: the particles are removed by rapid mucociliary clearance.
bb1 short-term retention (t½ about 8 hours) of particles in the bronchiolar
region: the particles are removed by rapid mucociliary clearance.
BB2 intermediate retention (t½ about 20 d) of particles in the bronchial
region.
bb2 intermediate retention (t½ about 20 d) of particles in the bronchiolar
region.
BBseq long-term retention (t½ about 70 d) in airway walls of a small fraction
of the particles deposited in the bronchial region.
bbseq long-term retention (t½ about 70 d) in airway walls of a small fraction
of the particles deposited in the bronchiolar region.
ET1 retention of material deposited in the anterior nose (region ET1, which
is not subdivided).
ET 2 short-term retention (t½ about 10 minutes) of the material deposited in
the posterior nasal passage, larynx, pharynx and mouth (region ET2), except
for the small fraction, taken to be 0.0005, retained in ETseq. (In Publication 66
this compartment was labelled ET2. It is here, as in Publication 71, labelled
ET to distinguish it from the region ET2 which also includes compartment
2
ETseq.)
ETseq long-term retention (t½ about 700 d) in airway tissue of a small fraction
of particles deposited in the nasal passages.
LNET lymphatics and lymph nodes that drain the extrathoracic region.
LNTH lymphatics and lymph nodes that drain the thoracic regions.
Revised HRTM
ET 2 short-term (t½ about 10 minutes) of the material deposited in the
posterior nasal passage, larynx and pharynx (ET2 region) except for the small
fraction (taken to be 0.002) retained in ETseq.
BB′ retention (t½ about 100 minutes) of particles in the bronchial region,
with particle transport to 2 T E .
bb′ retention (t½ about 3.5 days) of particles in the bronchiolar region, with
particle transport to BB′.
BBseq long-term retention (t½ about 700 d) in airway walls of a small fraction
of the particles deposited in the bronchial region.
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