Occupational Intakes of Radionuclides Part 1 - ICRP

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DRAFT REPORT FOR CONSULTATION
Fractional absorption in the gastrointestinal tract (f1)
The fraction of an element directly absorbed from the gut to body fluids, used
in the Publication 30 gastrointestinal tract model. See also ‘Alimentary tract
transfer factor’.
Habitual Mouth Breather
A person who breathes oro-nasally (partly through the nose and partly through
the mouth) at all levels of exercise: “sleep”, “sitting” “light exercise” and
“heavy exercise”. At “heavy exercise” such a person inhales a greater fraction
of air through the mouth than a Nasal Augmenter.
Habitual Nose Breather
A person who breathes entirely through the nose at the exercise level of
“heavy exercise” as well as at “sleep”, “sitting” and “light exercise”. Such a
person may switch to breathing oro-nasally (partly through the nose and partly
through the mouth), but at a ventilation rate greater than the reference value
for heavy exercise (3 m 3 h –1 ).
Human Alimentary Tract Model (HATM)
Biokinetic model for describing the movement of ingested materials through
the human alimentary tract; published in Publication 100 (ICRP, 2006).
Human Respiratory Tract Model (HRTM)
Biokinetic model for describing the deposition, translocation and absorption
of inhaled materials in the human respiratory tract; published in Publication 66
(ICRP, 1994a).
Inhalability
Fraction of particles that enters the nose and mouth, of those present in the
volume of ambient air before inspiration.
Intake. See also ‘Uptake’
Activity that enters the respiratory tract or gastrointestinal tract from the
environment.
Acute intake - a single intake by inhalation or ingestion, taken to occur
instantaneously.
Chronic intake - a protracted intake over a specified period of time.
Nasal Augmenter
A person who breathes entirely through the nose at the exercise levels of
“sleep”, “sitting” and “light exercise”, but oro-nasally (partly through the nose
and partly through the mouth) during “heavy exercise”. Also known as a
“normal nose breather”, because most people breathe according to this pattern.
All reference subjects, including the Reference Worker are assumed to be
Nasal Augmenters.
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