Assessment of the internal effective dose of workers independent of inhaled particle size (II).

For 60Co (Type S) and 54Mn (Type M), for which the whole-body content can be measured, it is possible to minimise the errors of the estimated effective doses caused by uncertainty of the activity median aerodynamic diameter (AMAD) by assuming the AMAD to be 5 microm and by measuring the body content on day 5 after inhalation. For the radionuclides to be measured in the lung content, e.g. 239Pu (Type S), it may be necessary to estimate the AMAD, because the lung burdens on any day are not always proportional to the whole-body content which reflects the effective doses. There is no problem in assuming the AMAD to be 5 microm for external counting and for urinalysis of Type F compounds, because of the rapid absorption of such compounds into the blood and the same biokinetics. The breathing rate is assumed to be 1.2 m3 h(-1).