A Review of the Dose Reconstruction Program of the Defense Threat Reduction Agency (2003) / Chapter Skim
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Appendix E: Analysis of Potential Inhalation Doses Due to Blast-Wave Effects at Operation PLUMBBOB, Shot HOOD, and Implications for Dose Reconstructions for Atomic Veterans
Appendix E: Analysis of Potential Inhalation Doses Due to Blast-Wave Effects at Operation PLUMBBOB, Shot HOOD, and Implications for Dose Reconstructions for Atomic Veterans
Pages 335-348
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From page 335... ...
The effect of a blast wave on resuspension of fallout that was previously deposited on the ground has been ignored in all dose reconstructions for atomic veterans, but the committee believes that the effect is potentially important and should be taken into account (see Section V.C.3.2, comment [71~. The results of the example analysis have important implications for dose reconstructions for other exposure scenarios involving inhalation of resuspended fallout, and these implications also are discussed in this appendix.
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From page 336... ...
On the basis of measured concentrations of longer-lived radionuclides in surface soil after the period of atomic testing shown in Figures E.1 through E.4, measured activity ratios obtained from soil samples (McArthur, 1991) , and the ICRP's current dose coefficients for inhalation of respirable particles (AMAD, 1,um)
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From page 337... ...
in vicinity of ground zero (GZ) of Operation PLUMBBOB, Shot HOOD based on measurements in middle 1980s (McArthur and Mead, 1987~.
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From page 338... ...
C: ~ ~~ EO70~0 HOOD GZ No E6020~ No FIGURE E.4 Distribution of concentrations of 152Eu in surface soil (nCi m-2) in vicinity of ground zero (GZ)
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From page 339... ...
In this analysis, potential inhalation doses due to effects of the blast wave at Shot HOOD are estimated by taking into account subjective estimates of uncertainty in all input parameters. Assumed uncertainties in parameters that are used to estimate airborne concentrations of plutonium are intended to represent a range of plausible conditions at different distances from ground zero and at various times after the blast wave occurred; the assumed uncertainties are not intended to represent plausible conditions of exposure that would result in the highest estimates of dose at a particular location and time.
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From page 340... ...
Breathing rate Organ-specific dose coefficients for inhalation of plutonium attached to respirable particles Time after exposure when cancer occurred in exposed person Lognormal distribution with 80% confidence interval of 20-200 nCi m-2 Uniform distribution over range of 0.5-1.0 Lognormal distribution with 90% confidence interval of 4-18 Lognormal distribution with 90% confidence interval of 10-4-10-2 m-1 Uniform distribution over range of 0.2-1.0 Lognormal distribution with 90% confidence interval of 0.6-1.7 m3 h-1 To account for uncertainties in dosimetric and biokinetic models used to calculate dose coefficients, lognormal distributions with 90% confidence interval of 0.1-10 times current ICRP recommendations for adult workers To account for uncertainty in biological effectiveness of alpha particles relative to photons and electrons, replacement of standard value of 20 used in ICRP dose coefficients with lognormal distribution with 95% confidence interval of 3.2-100 Reduces dose of concern to all organs and tissues other than the lung by factor of 2 aOther radionuclides in fallout from prior shots that were present at time of Shot HOOD and could contribute to inhalation doses are neglected. fraction of the assumed contamination at the time of detonation is due to fallout from prior shots, and it is possible that nearly all the contamination is due to prior fallout.
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From page 341... ...
Ratios of plutonium to 24iAm in safety shots are expected to be much higher than ratios in normal nuclear detonations and therefore are not relevant to estimating plutonium in deposited fallout at the time of Shot HOOD. · Concentrations of plutonium in air caused by the blast wave at Shot HOOD relative to concentrations in surface soil are described by a resuspension factor that has a lognormal probability distribution with a 90% confidence interval of 10-4-10-2 mat.
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From page 342... ...
, and Table V.C.6~. · The uncertainty in dose coefficients for inhalation of plutonium due to the uncertainty in the biological effectiveness of alpha particles relative to photons and electrons is described by a lognormal probability distribution with a 95% confidence interval of 3.2-100 (see Section V.C.3.2, comment [21~.
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From page 343... ...
, central estimates of inhalation doses due to resuspension caused by a blast wave in areas away from ground zeros of previous shots at the NTS would be about the same as doses in Table E.2 at locations, such as Area 4, where the background of local fallout is the highest. Thus, high inhalation doses are likely to have occurred only in cases of exposure in small areas near locations of previous shots where radionuclide concentrations are unusually high.
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From page 344... ...
E.5 IMPLICATIONS OF EXAMPLE ANALYSIS FOR OTHER EXPOSURE SCENARIOS The upper-bound estimates of inhalation dose in Table E.2 also indicate that credible upper bounds could be important in other exposure scenarios in which resuspension was caused by vigorous disturbance of surface soil. For example, as discussed in Section IV.C.2.1.3 and summarized in Table IV.C.2, resuspension factors as high as 1 o-3 m-i are assumed in scenarios involving assaults or marches behind armored vehicles at the NTS, and credible upper-bound estimates of inhalation doses in these scenarios could be within a factor of 10 of the estimated upper bounds in Table E.2.
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From page 345... ...
The approach to assessing inhalation doses at Shot HOODis indicated by a dose reconstruction for one of the participant groups (Frank et al., 1981~. In that analysis, the possibility that participants received an inhalation dose due to deposited fallout that was resuspended by the blast wave was dismissed with the statement that "what dust was lofted by the shock wave had either settled or blown out of the shot area, away from the troops, before the HOOD radiation field was entered" (Frank et al., 1981~.
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From page 346... ...
~ Landing Zone ~ Pink a\\~; vet J \ ~~ - ¢ Landing Zone \ Blue 1 1 1 Command Post / 0 Tracked Vehicle Assembly Area Legend: Helicopter Route ————Tracked Vehicle Route Marine Assault N Foot Route J (8) GZ _ I 1~ ~ - ~ Trenches Helicopter Loading Zone Two t l Main Equipment Display Area To Helicopter Loading Zone 1 and the Parking Area Approximately 9 km FIGURE E.5 Diagram of troop movements in forward areas after detonation of Operation PLUMBBOB, Shot HOOD at location marked "GZ" (Maag et al., 1983~.
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From page 347... ...
However, the committee believes that it is implausible to assume that troops continued to wear gas masks during the entire time spent in forward areas after the initial blast wave passed, even though dust concentrations remained high. The high temperatures on a July day and the presence of many brush fires in the area, which added to the heat and obscured visibility, made it difficult to carry out maneuvers while wearing respiratory protection.
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From page 348... ...
Stockholm, Sweden: International Commission on Radiological Protection. IT and DRI (IT Corporation and Desert Research Institute)
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