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.