Fetal dose assessment for the offspring of the Techa Riverside residents |
| |
Authors: | E I Tolstykh Marina O Degteva Marina I Vorobiova Vyachslav P Kozheurov |
| |
Institution: | (1) Urals Research Center for Radiation Medicine, Medgorodok, Chelyabinsk, 454076 Russia e-mail: evgenia@urcrm.chel.su Tel.: +7-3512-344384, Fax: +7-3512-344321, RU |
| |
Abstract: | Massive releases of fission products from the plutonium facility Mayak (Southern Urals, Russia) resulted in the contamination
of the Techa river and its floodlands (1949–1956). The results of long-term studies of exposure populations have been used
for different purposes of retrospective dosimetry. The riverside residents were exposed via various pathways and their progeny
were exposed in utero both to external radiation and to internal radiation from radionuclides ingested by the mothers prior
to conception and during pregnancy. Fetal doses due to 90Sr from the maternal skeleton were estimated and compared with doses from other pathways. Individual red bone marrow (RBM)
doses to the late fetuses were calculated on the basis of 90Sr contents measured in the maternal skeleton and the 90Sr transfer coefficients (TC) to the fetal skeleton were determined on the basis of the Techa river data. Two values of TC
were assumed depending on the mothers’ maturation status in the period of maximum releases: TC=0.2 for group 1 (adulthood
of mothers in 1950) and TC=0.02 for group 2 (mothers not yet in menarche age in 1950). Fetal doses in both groups that resulted
from the different TC values varied by a factor of about 5–8. Furthermore, the fetal RBM doses due to 90Sr from the maternal skeleton were found to depend on the distances from the site of release and the time after major 90Sr intake. The average fetal RBM doses in the population of the upper, middle and lower Techa riverside regions were close
to the ratio 3:2:1 and 20 years after the onset of contamination, the fetal doses have decreased by a factor of about 3–5.
The distance from the site of release determined the relative contribution of different pathways to the fetal dose. For the
settlements that are located closest to the site of release, the external exposure was of major concern up to the date of
evacuation. For the non-evacuated settlements, the contribution of internal doses was higher and after 1956, external exposure
is assumed to be negligible. From 1956 on, 90Sr that has been transferred from the maternal skeleton was practically the single source of in utero exposure.
Received: 8 December 2000 / Accepted: 1 July 2001 |
| |
Keywords: | |
本文献已被 PubMed SpringerLink 等数据库收录! |
|