Annals of the ICRP ICRP PUBLICATION 95 Doses to Infants from Ingestion of Radionuclides in Mothers” Milk

This publication on doses to infants from radionuclides in mothers milk is the last in a series on doses to members of the public, although, together with its immediate predecessor on doses to the embryo and fetus, it is also applicable to occupational exposures. The series began with Publication 56 (ICRP, 1989) which gave dose coefficients for a range of radionuclides ingested by members of the public, including infants and children, with subsequent reports giving values for other radionuclides and considering inhalation as well as ingestion (ICRP, 1989, 1993, 1995b,c, 1996). Publication 88 (ICRP, 2001) gave dose coefficients for the embryo, fetus, and newborn child from intakes of radionuclides by the mother before or during pregnancy. The present report considers transfer of radionuclides to the infant in breast milk for the intake times used in Publication 88 and additional times during lactation. It gives dose coefficients for infants following radionuclide intakes by their mothers, with values for members of the public in the main text and values for workers in Annex A. Annexes B and C give examples of doses to maternal breast tissue occurring during radionuclide transfer, and external doses to the infant from radionuclides in the mother s body, respectively. Annex D gives dose coefficients for the fetus for some additional radionuclides not included in Publication 88 (ICRP, 2001). A departure from previous custom in this report is a discussion of doses (Chapter 4). The main conclusion reached is that for most of the radionuclides considered, doses to the infant from radionuclides ingested in breast milk are estimated to be small in comparison with doses to the reference adult. This comparison is made with the reference adult because ICRP does not calculate doses separately for males and females. Comparisons of infant doses with doses specific to female adults would result in different numerical values but the same general conclusions. On the basis of the models developed in this report, it is only in the cases of tritiated water, Ca, Se, and I that infant doses may exceed adult doses, by ratios of between 1 and 3, applying to maximum transfer occurring after maternal intakes by ingestion shortly after birth. Ratios of infant to reference adult doses are generally lower for intakes by inhalation than for ingestion. Comparisons with Publication 88 (ICRP, 2001) doses to the offspring due to in utero exposures show that, in most cases, these are more important than doses that may result from breastfeeding; exceptions include Co, I, and Po. The discussion of doses in this report is deliberately short; further details will be published in the open literature, following an earlier publication of preliminary results (Harrison et al., 2003). Doses to the embryo