Occupational Intakes of Radionuclides Part 1 - ICRP

1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
DRAFT REPORT FOR CONSULTATION
maintenance of reactor facilities;
handling of radioactive waste, for example from nuclear facilities and
hospitals;
the processing of plutonium and other transuranic elements;
the processing of thorium ores and the use of thorium and its compounds
(these activities can lead to internal exposure from both radioactive dusts and
thoron [ 220 Rn] and its progeny);
the mining, milling and refining of uranium ores;
natural and enriched uranium processing and fuel fabrication;
work with large quantities of naturally occurring radioactive materials
(NORM);
the production of radiopharmaceuticals;
the handling of large quantities of 131 I for medical applications.
(77) The results of monitoring of the workplace may also indicate a need for a
temporary programme of special individual monitoring aimed at identifying any need
for a routine programme of workplace monitoring.
2.6 Female Workers: pregnancy and breast-feeding
(78) It is the Commission's policy (ICRP, 2007) that the methods of protection at
work for women who are pregnant should provide a level of protection for the
embryo/fetus broadly similar to that provided for members of the public. The
Commission considers that this policy will be adequately applied if the mother is
exposed, prior to her declaration of pregnancy, under the system of protection
recommended by the Commission. Once pregnancy has been declared, and the
employer notified, additional protection of the embryo/fetus should be considered.
The working conditions of a pregnant worker, after declaration of pregnancy, should
be such as to make it unlikely that the additional external dose to the fetus, together
with the committed effective dose to the fetus and newborn child from intakes of
radionuclides before or during the pregnancy, would exceed about 1 mSv.
(79) ICRP has provided information in Publications 88 and 95 (ICRP, 2001, 2004)
on doses to the embryo, fetus and newborn child following intake of radionuclides by
female workers either before or during pregnancy or during lactation. Comparisons of
fetal dose coefficients given in Publication 88 with corresponding adult dose
coefficients showed that doses received by a woman from intakes before or during
pregnancy will in most cases be substantially greater than doses to her fetus.
However, doses to the offspring can exceed doses to the mother for a number of
radionuclides. In particular, the requirements of skeletal development during fetal
growth, particularly in late pregnancy, can lead to significant uptake of radioisotopes
of phosphorus and of calcium and, to a lesser extent, other alkaline earth elements.
Thus, offspring:adult dose ratios were up to factors of about 10 – 20 for isotopes of P
and Ca and 2 – 6 for isotopes of Sr (Stather et al, 2003; ICRP 2004). Uptake of
radioisotopes of iodine by the fetal thyroid can also lead to greater doses to the fetus
than to the mother following intakes late in pregnancy (dose ratios of up to about 3)
(Berkovski et al, 2003b). Other radionuclides for which doses to the fetus can exceed
44