Transfer of alkaline earth elements in mothers' milk and doses from 45Ca, 90Sr and 226Ra.
An international programme of work is currently under way to develop methods for calculating doses to infants from ingestion of radionuclides present in mothers' milk. This paper considers the special case of the alkaline earth elements. Models have been developed for 45Ca, 90Sr and 226Ra and the sensitivity of results to various changes in parameter values is discussed. A complication when calculating doses from intakes of radium is that the International Commission on Radiological Protection has previously recommended that doses from decay products of radium should be calculated using element-specific biokinetic models (so-called independent biokinetics). An extension of this method to the models for breastfeeding is proposed. Preliminary estimates of the doses received by the infant for a number of maternal intake scenarios show that doses to the infant can exceed the corresponding adult dose, such as for 45Ca (ratio = 3.1) while, in other cases such as 90Sr, the infant dose can be a significant fraction of the adult dose.
Smith
T J
TJ
National Radiological Protection Board, Chilton, Didcot, Oxon, OX11 0RQ, UK. tracy.smith@nrpb.org
Phipps
A W
AW
Fell
T P
TP
Harrison
J D
JD
D000284:Administration, Oral; D001822:Body Burden; D002132:Calcium Radioisotopes / Q000032:analysis / Q000493:pharmacokinetics; D003198:Computer Simulation; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D018811:Maternal Exposure; D008673:Metals, Alkaline Earth / Q000008:administration & dosage / Q000032:analysis / Q000493:pharmacokinetics*; D008895:Milk, Human / Q000378:metabolism*; D008954:Models, Biological; D011247:Pregnancy; D011829:Radiation Dosage; D011868:Radioisotopes / Q000008:administration & dosage / Q000032:analysis / Q000493:pharmacokinetics*; D011874:Radiometry / Q000379:methods* / Q000592:standards; D011883:Radium / Q000032:analysis / Q000493:pharmacokinetics; D013326:Strontium Radioisotopes / Q000032:analysis / Q000493:pharmacokinetics
D002132:Calcium Radioisotopes; D008673:Metals, Alkaline Earth; D011868:Radioisotopes; D013326:Strontium Radioisotopes; D011883:Radium