Reconstruction of 90Sr intake for breast-fed infants in the Techa riverside settlements

Abstract

The Techa River (Southern Urals, Russia) was contaminated as a result of radioactive releases by the Mayak plutonium production facility during 1949-1956. The persons born after the onset of the contamination have been identified as the "Techa River Offspring Cohort" (TROC). The TROC has the potential to provide direct data on health effects in progeny that resulted from exposure of a general parent population to chronic radiation. The purpose of the present investigation is the estimation of (90)Sr intake from breast milk and river water in the period from birth to 6 months of life, necessary for an infant dose calculation. The investigation is based on all available data concerning radioactive contamination due to global fallouts and Mayak releases in the Southern Urals where extensive radiometric and radiochemical investigations of human tissues and environmental samples were conducted during the second half of the twentieth century. The strontium transfer factor from mother's daily diet to breast milk was estimated as 0.05 (0.01-0.13) d L(-1). Based on this transfer factor and data on (90)Sr water contamination, the average total (90)Sr intake for an infant born in the middle Techa River region was found to be equal to 60-80 kBq in 1950-1951. For the same period, calculations of (90)Sr intake using ICRP models gave values of 70-100 kBq. From 1952 onwards, the differences in intakes calculated using the two approaches increased, reaching a factor of 2-3 in 1953. The Techa River data provide the basis for improving and adapting the ICRP models for application to Techa River-specific population.

Maternal Mineral and Bone Metabolism During Pregnancy, Lactation, and Post-Weaning Recovery

“…Observational data and mathematical models predict that the amounts of 90 Sr, 45 Ca, 131 I, and other isotopes in breast milk will be highest when maternal exposure occurs in late pregnancy or while lactating, confirming that dietary intake remains a significant contributor to breast milk (1,366,851,924).…”

“…That the maternal skeleton contributes mineral to breast milk has been inadvertently confirmed by Techa River residents in Russia, who released 90 Sr into breast milk years after their exposure from ingestion of contaminated river water (924). Observational data and mathematical models predict that the amounts of 90 Sr, 45 Ca, 131 I, and other isotopes in breast milk will be highest when maternal exposure occurs in late pregnancy or while lactating, confirming that dietary intake remains a significant contributor to breast milk (1,366,851,924).…”

Irreversible Deterioration of Cortical and Trabecular Microstructure Associated With Breastfeeding

“…(1) Radioisotopes that were deposited in the skeleton years earlier are released to enter breast milk. (4) Lumbar spine BMD, as assessed by DXA, declines by a mean of 5% to 10% among numerous studies during 3 to 6 months of exclusive lactation, whereas largely cortical sites (hip, forearm, whole body) show less than half that loss or no significant changes. (1) This is consistent with the animal data in that the trabecular-rich spine is more greatly affected than the appendicular skeleton.…”

Incidence and Mortality of Solid Cancers in People Exposed In Utero to Ionizing Radiation: Pooled Analyses of Two Cohorts from the Southern Urals, Russia

“…ICRP-88 models [ 20 ] were applied to calculate the in utero doses from 137 Cs. Dietary intakes of 89,90 Sr and 137 Cs for adult Techa riverside residents [ 21 , 22 ] were adjusted for the increase in food consumption by pregnant women [ 23 ]. External in utero doses were calculated using TRDS-2009D, considering exposure of the maternal uterus as a surrogate of the fetal exposure.…”