doses to nz sailors at the grapple tests johnston
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Doses to NZ sailors at the Grapple Tests
Peter Johnston, Peter Burns, Stephen Solomon, Rick Tinker, Jordon Lock
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Code Name: Operation Grapple
Kiritimati (Christmas) Island and Malden Island
http://teraina.com/img/Line_Islands.jpg
• 551 Personnel
• 2 New Zealand frigates HMNZS Rotoiti
HMNZS Pukaki
• 32‐240km from GZs
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Code Name: Operation Grapple
UNSCEAR 2000 Report to the UN General Assembly Volume 1: Sources
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Reports of the Massey Group
• Dr. Rowland (Massey University) was funded by the NZ Government led Helen Clark and the NZ Nuclear Veterans
Association.
• Dr. Rowland and team also investigated DNA damage in NZ Vietnam Veterans.
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Conclusions of the study (Wahab et al.)
(pp. 85; Wahab et al, 2008)
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ARPANSA analysis: Radiation Exposure Pathways
• For a radiation exposure to occur there needs to be a source and
a pathway.
• Two obvious potential pathways are present
(i) direct exposure at the time of detonation of the nuclear explosion
(ii) internal and external exposure from airborne and surface deposited fallout.
Wahab et al. (2008) do not explicitly identify a pathway, they state that their “finding is evocative of irradiation”
and further suggest that the veterans
may have been contaminated and may have retained high‐LET long half‐life radionuclides in their bodies (Rowland et al., 2005).
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Radiation Exposure Pathway
• Doses from irradiation will be insignificant at distances
beyond 10 km. – Closest was 32 km away from
ground zero
– Maximum Distance 240 km
External Pathway Fallout Pathway
• In the first few weeks after
detonation, high LET long lived
alpha emitters are not present
without large amounts of gamma
and beta emitters that would have
been observed by the monitoring
Crouch et al (2009).
• Rowland et al. (2007) states that
there is no monitoring data from
the tests.
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1999 NZ Cabinet Inquiry
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Wind Direction
The ships were 20 to 150 nautical miles (32 to 240 km) upwind.
Being upwind suggests there is no fallout in the vicinity of the ships that could
result in contamination of the sailors or the ships.
Wind dir
ection
Ship Loca
tions
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Control Group
The obvious Control Group is naval servicemen who were active on vessels not involved in the Grapple Tests at the same time. This
would have controlled for diet and life‐style differences that may be unique for naval personnel.
Wahab et al. study of ex‐naval personnel are excluded on the basis that the ships might not be ‘clean’
–
suggesting that all New
Zealand naval ships are contaminated with radioactive material.
There are many potential environmental factors on board ships (e.g. exposure to fuel, asbestos and ordinance)
This is a significant experimental design flaw.
IAEA recommends that biodosimetry studies using
chromosomal aberrations should be restricted to scoring to 1 or 2
way translocations or complex aberrations such as dicentrics.
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Biological Dosimetry
Wahab et al., (2008) report higher observed frequencies of dicentric and
acentric chromosomes as being “evocative of irradiation”
and suggest that
appearance of dicentrics in Veterans is evocative of exposures from 50 years
prior!
Dicentrics are reduced substantially with time i.e. within weeks/months and
are unsuitable for analysis when a period of years has elapsed since exposure.
Wahab et al. results
‐
dicentrics observed in Veterans are typically 1‐2 cells per 1000
(IAEA, 2001) accepted as normal background.‐
80% of Veterans had no dicentrics at all.
The observation of more dicentrics in Veterans than controls appears due to
an abnormally small number of dicentrics in the controls.
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Biological Dosimetry –
Dicentric Chromosomes
Robertsonian translocations are the most common structural abnormality of human chromosomes—observed in approximately 1 in 1000
individuals.
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Biological Dosimetry – Translocation Chromosomes
Contrary to the claims of Wahab et al., translocations yields of
the Veterans are neither elevated nor significant as they fall within the range
observed in age‐matched controls found in other studies.
Wahab et al. used the freshly irradiated blood of a single healthy 60 year old donor to estimate the doses to which participants had been exposed 50 years previously.
This raises several methodological issues: • Calibration by a single point ‐
significant variability from one individual to
another is seen in other studies related to biological dosimetry• In vitro irradiation of blood compared with in vivo exposure • The lack of any analysis of the impact of body repair mechanism over 50
years since veterans served at Grapple• The donor is younger than the test participants • In Rowland et al. (2007), a different calibration using three healthy blood
donors of average age 40.5 years was used which indicated doses more than twice as high.
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Calibration
• The report of Wahab et al. (2008) does not mention the dose received by
background radiation from natural sources or medical exposures other than
radiation therapy.
• The background is significant over a lifetime and needs to be taken into account
in considering the doses reported.
• Using 2.1 mSv/year would result in a mean background dose of 140
mSv (140
mGy for low LET radiation) for both veteran and control groups.
• Wahab et al., estimate an average 170 mGy dose for veterans while the values for
controls averages 37 mGy.
• The dose calibration method has not provided dose estimates that
are credible.
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Background and Assessed Radiation Doses
• Available data on exposures of the New Zealand sailors witnessing the Grapple tests shows no significant dose.
• No pathway for exposure is identified.
• The selection of the control group is not designed to isolate the effect of interest.
• The dose calibration methodology does not calibrate the situation of interest.
• Biological dosimetry does not conform to accepted methodologies and is untested.
• Background exposures are comparable with doses estimated, but the background is ignored.
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Review Conclusions
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Why critically review their claims...
• Flawed science
• Heartache for victims
• Wasted resources
• Defence against litigation
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Thank you