lleOe
percent in 80 years.
of the rooting zone will
Removing 30 cm of topsoil
a
fall
by some 85
will
reduce the level
by
fall
in direct. propartion
some 66 percent (Table 2).
It should be noted that dose does not
to the depth of such excavation.
Since dose
is
proportional
to
rooting-
zone specific-activity, it falls exponentially with depth like the rooting-
zone activity (Figure 4).
mare:
lhlUrlUlUmrecEElUlU
The strontium-90 level
I00062b
27