Rate and route of excretion of systemic thorium from the human body in occupational subjects and its implications in bioassay monitoring.
Explore the source record for details and available documents.
Body Burden↗
Biomedical subjects
D D Jaiswal
Publications and source records attributed to D D Jaiswal.
Studies on the biological half-lives of three important radionuclides released in nuclear power reactor operations.
The four important parameters involved in the calculation of internal radiation dose to the human body, per unit intake of a radionuclide are 1) weight and size of the body organs; 2) the biological (retention) half-life of the radionuclide; 3) radiation weighting factors for the type of radiations emanating from the radionuclide; and 4) the organ weighting factors for the organs being irradiated (target organs). Whereas, for a particular radionuclide, the radiation weighting factor and the organ weighting factors may remain constant for all humans, the other two parameters, namely, the organ weights and biological half-life, are population specific and may differ from one population group to another. For a realistic dose estimation, the population specific data on organ weights and biological half-lives for various radionuclides therefore, are needed.
Adult↗
ICRP recommendations of the derived thorium excretion levels for occupational workers--a viewpoint.
Explore the source record for details and available documents.
Body Burden↗
A sensitive method for the determination of Th in body fluids.
A method involving neutron activation followed by simple radiochemical separation was developed and applied to determine the concentrations of Th in blood serum and urine. The method is sufficiently sensitive to detect 0.025 ng of 232Th. The average concentration of Th found in the blood serum and urine of subjects from normal environments is 7.9 ng L-1 and 2.7 ng L-1, respectively.
Humans↗
Daily intake of thorium by an Indian urban population.
Thorium intake by an urban group (Bombay) has been estimated using neutron activation followed by simple chemical separation. Daily intake of thorium via all the three sources: food, water and air, is reported in this paper. The major contribution of thorium to intake is through food (2.0 micrograms), followed by water (0.02 microgram) and air (0.02 microgram). The individual food ingredients such as cereals, pulses, vegetables, milk, etc. were also analysed for their thorium content. The cereals were found to contribute most to the daily intake.
Environmental Monitoring↗
Breast feeding: Mo, As, Mn, Zn and Cu concentrations in milk of economically poor Indian tribal and urban women.
The breast milk of 86 economically poor Indian women was analysed by neutron activation analyses for Mo, As, Mn, Zn, and Cu concentrations. The colostrum of 10 tribal women contained 0.27 microgram Cu/g, 2.1 micrograms Zn/g, 19.9 ng Mn/g, 0.73 ng As/g and 5.4 ng Mo/g, whereas 19 urban women had corresponding concentrations of 0.91 microgram Cu/g, 7.3 micrograms Zn/g, 15.3 ng Mn/g, 0.5 ng As/g and 15.3 ng Mo/g. A survey of mature milk between 1 and 6 months, 6 and 12 months and 1 and 2.5 years indicated decreasing concentrations of Zn and Mo, but increasing Mn concentrations as the post-partum period progressed. Malnourished infants received breast milk containing less Cu, Zn and Mn than those who were better nourished and of the same age group. The results, therefore, imply the necessity of supplementing breast feeds in the economically poorer groups.
Arsenic↗
Concentrations of four essential trace elements in breast milk of mothers from two socio-economic groups: preliminary observations.
Concentrations are reported for Cu, Mn, Mo and Zn in human milk samples obtained from mothers belonging to low and middle per capita family income groups. The trace element levels in milk of both groups are compared for samples obtained at two stages, viz. 3-5 days and 4-6 weeks post partum. Although the Mn level during the first stage appears to be lower in samples from the low income group, the difference is not statistically significantly (p less than or equal to 0.01). However, at 4-6 weeks post partum, Zn is significantly lower (p less than or equal to 0.01) in milk of mothers belonging to this group.
Copper↗
Distribution of arsenic in human tissues and milk.
Using neutron activation followed by radiochemical separations, the arsenic contents of various human tissues and milk were determined. The reliability of analysis was established by analysing a number of standard reference materials. The concentrations in different human tissues range from 1.6 ng As/g (fresh weight) in kidneys to 2140 ng As/g in hair. The mean arsenic levels are compared with those reported from other countries.
Arsenic↗
Trace element changes in hair during pregnancy: preliminary study.
Using neutrons activation analysis, the changes in concentrations of Cu, Zn and Mn in hair during pregnancy are studied. Scalp and pubic hair samples from both non-pregnant and pregnant female subjects were analysed. The results of this preliminary study are presented. Cu, Zn and Mn levels in scalp hair obtained from pregnant subjects were not significantly different from those of non-pregnant subjects. However, pubic hair samples obtained from subjects in the ninth month of pregnancy showed significantly lower Zn levels whereas Cu and Mn levels remained normal. Studies on two subjects in the last trimester showed a steady fall in Cu and Zn levels in pubic hair with advancement of pregnancy; Mn level did not, however, show any change. The reliability of analysis was checked using standard reference materials, such as Bovine Liver and Orchard Leaves (U.S. NBS).
Adult↗
Infants with a congenital anomaly and the concentration of Mo, As, Mn, Zn and Cu in the mother's milk.
Thirty-one samples of mothers' milk were analysed by neutron activation analysis for the concentrations of Mo, As, Mn, Zn, Cu 1.5 to 3 months post-partum. Group I consisted of 6 mothers having infants with neonatal obstructive jaundice and exhibited lower mean values of Cu and Mn at 0.18 microgram/g and 11.7 micrograms/g as compared with 16 control subjects with 0.34 microgram/g Cu and 23.0 micrograms/g Mn;Mo levels were approximately twice as high (12.2 micrograms/g) as the control values (6.4 micrograms/g); Zn and As were grossly comparable. Group II consisted of 9 mothers who had delivered infants with either a congenital hydrocephalus (n = 7) or meningomyelocoele (n = 2), exhibited a mean Cu level of 0.27 microgram/g, Zn 1.7 micrograms/g, Mn 25.3 micrograms/g and As 0.45 microgram/g. These findings are discussed in the light of the patho-physiology of the congenital anomaly of the infant.
Arsenic↗