A simple method employing neutron activation and radiochemical separation was developed for simultaneous determination of the concentrations of232Th(Th) and238U(U) in biological materials. Using this method, it is possible to detect 0.05 and 0.2 ng of Th and U, respectively, in the samples. This method was applied to determine the daily dietary intake of these two nuclides by the population living in the high background areas of India (Monazite area), where the soil contains very high levels of these two nuclides. The comparison of the daily intakes by the population living in high and normal background areas showed significantly higher intake of these two nuclides by the high background population.
Authors:H. Dang, D. Jaiswal, V. Pullat, and U. Mishra
The blood serum is the fluid medium through which most of the minerals are absorbed into the human body and get metabolized. The concentrations of Th in blood serum is in equilibrium with the content of Th in human body and therefore could reflect its content in the body. The daily intake (ingestion and inhalation) and the corresponding concentration of Th in blood serum of a group of subjects living in the high-background (monazite) area of Kerala State were measured and compared with the daily intake and corresponding blood serum concentrations of Th in three other groups of subjects namely: (1) those living in normal background area, (2) administrative staff working in Thorium Plant but not directly exposed to Th and its compounds, and (3) the occupational workers from Thorium Plant working for a time period in the range15–30 years. The Th concentration in the blood serum of subjects from high background area were found to be only marginally higher in comparison to the similar data from normalbackground area, which indicated that internal exposure due to Th to the subjects living in high background is quite low.
Authors:H. Dang, V. Pullat, D. Jaiswal, M. Parameswaran, and C. Sunta
The daily intake of uranium (238U) by an urban Indian adult population was estimated by the analysis of a duplicate diet, drinking water, and air samples using neutron activation and radio-chemical separation. The uranium intake through food is 0.55 g which is much larger than that from drinking water and air, at 0.09 and 0.01 g, respectively. The total daily dietary intake of uranium, calculated from the concentrations measured in the individual food ingredients and their daily consumption (based on the national survey), is found to be 2.2 g which is a factor of 3.5 higher than that based on a duplicate urban diet. The maximum contribution to the daily intake is found to be from cereals. The lower intake by the urban population is most likely due to their lower food consumption.