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biologically available form, are taken up by a critical
tissue or organ of the body,
are highly ionizing and have
both a long physical and a long biological half life.
~
The MPC values for radioisotopes in drinking water,
including water in foods,
given in Handbook 69 assumes that
there is no other source of contamination and that the
daily water consumption is 2.2 liters (or kilograms) per
day for a 50-year exposure period during which the level of
radioactivity remains constant.
The MPC values for drinking
water can be used for fish or other foods when compensation
is made for the difference between the calculated water
intake and the actual food intake.
If fish are the only
source of radioisotopes in the diet and 0.22 kilogram
(1/2 pound) of fish which is 1/10 of the water consumption
upon which the MPC values were based is eaten every day for
50 years,
the MPC values for fish would be obtained by
multiplying the values given in Handbook 69 by a factor of
10.
The assumption of one-half a pound of Fish per day in
the diet is nearly twenty times the average consumption
per capita in the United States (Taylor 1951) but would
be approximately the amount in the diet if fish were the
only source of protein.