Table 35.
(Continued)
Island
Well
Enidrik
Enidrik
DDS1
ODS1
11-07-78
04-20-79
3.9
18
Nam
Nam
CTS1
CTS]
11-12-78
04-25-79
14
2
Nam
NOTE:
Date
Salinity
ppt
CTS]
02-28-81
137¢5
90s,
239+240p,y
pci/-
pCi/L
fFCI/L
-5.3
-—
--
140
130
94
26
--
---
140
250
16
--
29
Dash indicates no data available.
In general, the radionuclide concentrations in the groundwater
lens
reflect the average radionuclide concentrations in the soil above it.
Eneu
Island has a tremendous freshwater lens, the quality and volume of which is
exceptional (Peterson and Underwood, 1987). On Eneu Island, the !3/cs, 90sr,
and 239+240py concentrations in the ground water are low and in all cases
below the EPA guidance of 8 pCi/L for 90sr, 91 pCi/L for !37Cs, and 15 pCi/L
for transuranic radionuclides for drinking water (based on 2 L/d intake and a
4 mrem/y limit) (40 CFR 141.15).
On the other hand, the 9Sr concentration
for Bikini Island generally exceeds the EPA guideline.
However,
in most
cases, Bikini Island ground water is so saline that it is nonpotable.
The
salinities in the ground water on Bikini and Eneu Islands have increased since
1975; this observation will be dealt with in more detail in the Discussion
section of this report.
The radionuclide concentrations are very low in the collected rainwater
(cistern water), which is the major source of fresh water for the island
residents. All the measured concentrations from 1975 to 1984 are well below
Current EPA guidelines for drinking water.
In
1978,
when
the
people
radionuclide concentrations in
were
relocated
cistern
from
Bikini
water increased
as
Atoll,
a
the
result
of
vegetation that grew around the cisterns at heights well above the top of the
cisterns.
Consequently, considerable vegetation containing !37Cs started
falling in openings in the top of the cisterns and accumulating in the bottom.
57