-32-
HW-80991
Surveillance of the milk available to people living near the Hanford
plants included samples from local farms and dairies and samples of commercial supplies sold in local stores.
The concentrations of radionuclides
found in the milk sold by stores was similar to that reported by the U. S.
Public Health Service and the Washington State Department of Health. (10)
Milk from farmsirrigated with water pumped from the Columbia River
downstream from the reactors contained p32 and zn®° as well as the fission
products of fallout origin.
The sr°?
.
concentration in milk known to be of local origin ranged
from less than 2 to 21 pc/1 as shown in Figure 12.
Such values are similar
to concentrations found in commercial milk produced in areas that could not
be affected by the Hanford plants.
The average concentration of sr9° in
milk produced in the Hanford environs during 1963 was about 12 pe/1 which
is among the lowest concentrations in the nation.
A temporary increase in
sr? was noted during the spring as a result of the seasonal influx of world~
wide fallout.
Concentrations of sr°? and Cs 137 in milk analyzed at Hanford
were generally below the detection level of 4 pc gr°9/) and 30 pec Cs 137 1
World-wide fallout is the principal source of these radionuclides in milk.
Measurements for I
1963.
131
were made on all milk samples collected in
The results of these measurements are illustrated in Figure 13.
During the early part of the year, I 131 concentrations were well below
10 pc/l and were following a generally decreasing trend.
The seasonal in-
flux of world-wide fallout, which began in May and reached a peak in
June, resulted in a maximum concentration of 84 pe/l
on June 19,
1963.
Activity levels then decreased rapidly to levels of 10 pc/1 or less.
In early September, I
131
concentrations in milk again increased as
a result of the inadvertent release of 331 from a separations plant previously
described.
The milk sampling program was increased in September and
October andthe maximum concentration actually measured was 140 pc p3ly
in a sample collected in the West Richland-Benton City area.
131
mated that the highest thyroid dose resulting from the I
It was esti-
release was prob-
ably received by a small child residing at the farm where the maximum milk