Mortality of Veteran Participants in the CROSSROADS Nuclear Test (1996)
Chapter: Appendix D: Radiation Doses for CROSSROADS Participants and Exposure Surrogate Groups
D
Radiation Doses for CROSSROADS Participants and Exposure Surrogate Groups
Although a recent Institute of Medicine (IOM 1995a) study found that Defense Nuclear Agency (DNA) dose data are unsuitable for dose-response analysis (see Chapter 8), a subsequent report (IOM 1995b) noted that these data may provide a rough estimate of the magnitude of doses received by the Atomic Veterans:
Of 210,000 participating veterans, about 1,200 received doses that were estimated to exceed 50 mSv (5 rem), which is the present annual exposure limit set by the U.S. Nuclear Regulatory Commission for workers occupationally exposed to radiation. About 20,000 participants were assigned doses that exceed the more conservative annual occupational limit, 20 rosy (2 rein), proposed by the International Commission on Radiological Protection. A total of 0.07 percent of the doses exceeded 100 mSv (10 rem), while the average dose for the Atomic Veterans was 6 mSv (0.6 rem). Although the dose assigned to a given veteran might change with further study, the distribution of doses across the cohort is unlikely to change significantly. (p. 70)
According to DNA figures, the CROSSROADS participants received doses that were, on the whole, smaller than those of other nuclear test participants.
The IOM (1995a, p. 13) study also noted that, ''Although there is anecdotal evidence that individual doses may have been greatly underestimated in individual cases, the overall tendency may have been to overestimate both external and internal doses.'' Even so, the doses of record for the CROSSROADS participants are comparable in magnitude and variability to the additional doses received in one decade by residents of the Rocky Mountain region as compared with those received by residents of the rest of the United States. The lifetime doses received by CROSSROADS participants are well within the range of lifetime doses to the U.S. population resulting from naturally occurring radiation sources.
It is conceivable that a subset of the CROSSROADS participants, because of their specialized training, may have pursued careers in radiation sciences either within the services or as civilians (e.g., as health physicists, nuclear reactor operators, or nuclear engineers). It is probable that this group accrued substantially higher radiation doses after CROSSROADS than during the test itself. We have no means of controlling for this possibility.
Although the radiation doses to the CROSSROADS cohort appear low, veterans have been vocal in their assertions that they are significantly below what they should be, based upon their firsthand observations of conditions at the test site. That makes it all the more desirable that this study base its analyses on exposure factors other than these dose estimates.
A summary of the DNA-assigned doses for the boarding and occupational specialty categories are shown in Figure D-1 and Table D-1. Again, note that these categories were derived independent of any dose information.
Figure D-1
Mean Doses (taken from DNA estimates) for Occupational Groups by their Status as Boarders or Nonboarders. See Chapter 8 for a description of occupational categories.
TABLE D-1. Tabulation of DNA Assigned Total Doses (rem (cSv)) by Study Grouping and Status as a Boarder or Nonboarder
|
|
Mean |
|
25%ile |
|
50%ile |
|
75%ile |
|
Max. |
|
|
|
Boarder |
Non-boarder |
Boarder |
Non-boarder |
Boarder |
Non-boarder |
Boarder |
Non-boarder |
Boarder |
Non-boarder |
|
EH-Jr. |
0.709 |
0.631 |
0.362 |
0.418 |
0.706 |
0.689 |
1.001 |
0.783 |
2.356 |
2.548 |
|
EH-Mid |
0.742 |
0.538 |
0.303 |
0.143 |
0.660 |
0.575 |
1.100 |
0.761 |
3.370 |
2.548 |
|
EH-Sr. |
0.778 |
0.538 |
0.337 |
0.117 |
0.703 |
0.592 |
1.118 |
0.752 |
2.806 |
2.561 |
|
Other-Jr. |
0.662 |
0.248 |
0.265 |
0.009 |
0.564 |
0.227 |
1.011 |
0.291 |
2.650 |
1.812 |
|
Other-Mid |
0.674 |
0.234 |
0.259 |
0.001 |
0.586 |
0.213 |
1.001 |
0.277 |
3.130 |
2.609 |
|
Other-Sr. |
0.704 |
0.236 |
0.262 |
0.001 |
0.586 |
0.212 |
1.013 |
0.277 |
3.245 |
2.251 |
|
Officer |
0.629 |
0.208 |
0.233 |
0.002 |
0.477 |
0.199 |
1.001 |
0.272 |
2.920 |
3.7323 |
