RESUMEN
A research program related to the assessment of toxic heavy metals and essential trace elements in foodstuffs has been carried out in 12 countries under the auspices of the IAEA. The main purpose of this program was to obtain data on the elemental concentrations of potentially toxic elements in foodstuffs in various countries, and to compare them with the maximum permissible levels specified in national legislation and international guidelines. High-priority elements for this study were As, Cd, Cr, Pb, Hg, and Se. Also of interest, but of lower priority, were Sb, Cu, and Zn. Emphasis was placed on the use of nuclear and nuclear-related analytical techniques, complemented by conventional methods, and on quality assurance.
Asunto(s)
Análisis de los Alimentos , Metales/análisis , Humanos , Análisis de Activación de Neutrones , Oryza/química , Control de Calidad , Oligoelementos/análisisRESUMEN
The concentration of thorium in the blood serum and urine of Western Australian mineral sands workers was studied to complement estimates of radiation dose derived from air sampling measurements. The concentration of thorium in urine samples from occupationally unexposed persons and pooled serum samples was also investigated. The concentration of thorium in the urine of the workers varied from 3-210 ng L-1 (geometric mean = 31 ng L-1, n = 34) while the concentration of thorium in the serum varied from 170-2,000 ng L-1 (geometric mean = 480 ng L-1, n = 25). No correlation was found between the bioassay results and cumulative airborne thorium exposure. The geometric mean ratio of daily excretion of thorium in urine to total thorium in the serum pool was 2.5%, considerably lower than the value of 10% proposed by the ICRP. These data indicate that more information is required to clarify the biokinetic models for thorium and that doses assessed from air sampling data must be interpreted with caution.
Asunto(s)
Minerales , Minería , Exposición Profesional , Torio/metabolismo , Contaminantes Radiactivos del Aire , Bioensayo , Humanos , Metales de Tierras Raras , Torio/sangre , Torio/orina , Australia OccidentalRESUMEN
A series of 20 mother-infant pairs were studied in Brisbane, Australia, at 6-12 weeks postpartum. The mean selenium concentration in maternal blood was 101 (SD +/- 19) ng/g and in maternal serum 81(+/- 15) ng/g; serum values appeared low in comparison with those reported for lactating women from Japan and the USA, but similar to those from Finland and from a previous Australian study. Breast milk selenium concentrations (11.9 +/- 3.5 ng/g) were also low by international standards, but not as low as in New Zealand or Scandinavia. There was no correlation between selenium concentrations in milk and blood (or serum). The infants' 24-h breast-milk intakes were 856 +/- 172 g, and their 24-h selenium intakes 10.7 +/- 4.1 micrograms (compared to the Australian RDI of 10 micrograms).
Asunto(s)
Fenómenos Fisiológicos Nutricionales del Lactante , Lactancia/sangre , Leche Humana/química , Madres , Selenio/química , Adolescente , Adulto , Humanos , Lactante , Masculino , Encuestas Nutricionales , Queensland , Selenio/sangreRESUMEN
Presented is a study, using multielement neutron activation analysis, of the elemental composition of blood plasma and milk in a group of lactating Australian women. Having established baseline values for nine elements, the authors studied factors affecting concentrations in milk and the partitioning of those elements between plasma and milk. Changes in this partitioning with the progression of lactation were demonstrated, and their nutritional implications for the exclusively breast-fed baby discussed. Progestogen-only oral contraceptives had no significant effect on levels of any of the trace elements in either blood or milk.