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4 8 APPENDIX II
vicinity of TAPS site have been constantly measured with therm o­
luminescent dosim eters (TLD) installed at village centres in different
directions from the site. The dosim eters were charged once in
3 months and annual dose was evaluated by summing up the quarterly
doses. The dose during 1968, 1969 and 1970 is in the natural
background radiation level.
Only during 1971 Akkarpatti village, which is about 1.8 km south
of site, had about 7 mR and Ghivali village, which is 1.8 km north
of site, had about 5 mR dose higher than normal background
radiation. This higher than background dose during 1971 was seen
during the month of June-July 1971 and at the same time power
station stack releases were going up frequently to 500-580 m C i/s.
Daily intake through seafood and critical group of population
It has been seen that except seafood no other dietary item can
contribute significantly to the daily intake from radioactivity d ischarged
from Tarapur Power Station under normal conditions.
Thus it is sufficient to consider the daily intake of seafood by the
different groups of population in the Tarapur environment to evaluate
the intake of the critical nuclide. The seafood intake of the main group
of Tarapur population is taken from the diet survey data.
Using the average nuclide concentration in seafood during 1970
and 1971 from Tables III and IV, the daily intake of critical nuclides
by the different groups of population has been evaluated. It has been
found that on average only 75% of weight of fish is used in preparing
food and 25% is discarded as non-edible. The data given in the
present study concern the edible portion only. It is observed that
fishermen in the TAPS environment, whose seafood intake is about
3 times higher than that of other groups, have the highest intake of
TAPS-released radioactivity. Thus they are the critical group of
population for TAPS discharges.
UNITED KINGDOM
Analysis of alternative hazard assessment approaches [17]
The critical pathway approach
The critical pathway approach has as its basis a hazard evaluation
(Table V), which uses predicted concentrations in the receiving
water mass resulting from unit rates of introduction of radionuclides.