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0- DEFENSE NUCLEAR AGERCY Ik. IWCe i?. kkchholz of the Departmnt of Energy reques~ed in his letter dated 2 Aug 79 that the Defcns~ Ruc~eU *encyxe~zew&io copy of your xeport, Vprel~r~naw Rcassc$sment of the potential - “logical Doses for Residents Resettling Enewetak Atoll,l~ dated 23 JuI 790 are attachad. Enclosures 1 and 2* d reasonably adequate data. I%e data that axe lvailable sre good. wmr$ there are several sppaxent weaknesses which are identified in the Rtttched general and specific cements. Resolution of these itens shbuld mst happy to xeview any subsequent drafts of this docunent. . BEST COPY AVAILABLE
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2. 7he report is clearly stamptd “dmft” and it cautions the reader throughout-that results are tehtttive. next yem or two.” evaluation of only *bout 2S percent of c. Page 2: %e are currently evslutt{ng the data,.. tu detemine md subsequent assessments will be done later.” f. Page 3: “insufficient time to lvslumte the diet sUrveYe.. and t* Page 20: ‘%e draft zeprt will be tqsnded to include CS 137 k. Page 46: ‘hot yet lvsilable and doses fxtm this source will Inwieu of the above. it Would be unwise for lither the U.S. or Micxonesian governments to cite this draft report l s a basis for altering cleanup snd xchsbilitation plans. In the spring 197S, LLL produced s draft dose lstimate study which considered transurmic elements only. ‘i%is study was the basis for DoE xccomending that cleanup guidelines be mdcmre strirtgent and for -estimates were high by s factor of ten due to =rithnetic error. TM guidtli: change had not bsen necessary.
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The Enewetak cleanq and rehabilitation plans Mm sdopted sfter lxtensive zwiew over 8 period of stvtr81 years in accordxace with the envircmental *act statement process. A change my be in 0r4tr at th!s time; however, the basis should be moze than the qualified draft. new in hand. ~cco=~end the suthors add apreamble to the report which wuld state that fn $plte of the xesemations mentioned, dose predictions giv:n sre the nest xellistic which csn be made at the present time and results arc unlikely to be changed si~ificsntly when rcmining uncertainties sre llaminated. [If justified) 2. ?here me several lreas of the report which hsve lpparent weaknesses. One relates to the sanple grid systmwhichprotidts precise masurenent of rsdionuclide content based on the point where the smple i$ ttkene ~~en this method is used to conpute the “average “ value for an entire island~ the island’%verage’~may indeed be higheror louer than themy isolated spots. Asecond c;ncern is in the lresofdatx ontheupttke of radionuclides by the food CtOps. Measureznents lppear to be f~rly Malted. AtMrdplace inuhichdatt sre ltss than dtsirsble is in the quantitstion of diet - howmch of which types of food are consuned by individuals daily. AS 8 corollary to the preceding two pamgmphs, it is worth xecalling that dose cstinates on which the Enewetak Clemup were based had ingestion as the pathway leading to highest dose. Within this pathway, breadfruit and pandanu! time uore significant contributors to dose than coconut. WO-140 dose predictions lead to reccmnendations that residence lnd 811 agriculture should be allowed on Enjebi, but it yielded to thou coconut agriculture onnorthcrn islands. 7he present dose estiutes for Enjebl consider breadfmit md Fandw grown on Enjebi without consequence, lnd encourage residence for Enjtbi if coconuts tre grokm on southern islands, The draft study reparts that vegetsb squash is relatively good at taking up radionuclides, but that does not Showup in the estimtes becmse the pCOpIC did not list squash in their diet questionnaire. But what assurance is there thst the dri Enjebi will net turn to squash or som other locally gmm vegetable which is as lffecti~~e in lbso: ‘fng radionuclidesl h ~kt happens when we know lnd utilize the uptake of chickens and eggs in lieu of le~ves and rat neat? Recommend that where possible these types of questions be addressed in the report.
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thns for proposed altenste living pstterns. lhe report would be mxe valuable if it also refined predictions for the planned living pattern SS defintd by Case 3 of the EIS. (’i%e proposed llternate living psttem @st siruilar to Cast 3 differs, for exmple, in thst tt does not allow from northeast islands to 10 percent rather than 40 percent. } A =view .of dose predictions for Case 3 was dccned necessary when high doses were discovered for people of Bikini Atoll. The DDEreco=nended sgainst the p~anting of coconut trees on northeast islands of Enewetak Atoll, *S h*d
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.4. Pqe 4, pxrlgraph 3. Nstural baclcground is Siven as 3.5 uR/h (ShOMTI . lDdividual risk is dependent on total dose, not just that received fran nucleaT weapon test debris. ‘T%us, reco=end the report justify the edssion 5. Psge S, Iast.sentence. Exponential depth distributions are not necessarily rt~$onable and frequently soil smple data demonstrates some other distribution which may not be amenable to snalytic=l expression. Thus, lbout one-third of the NVO-140 profile dsta fail to shou an exponential depth decrease. Tables 2-4 indicate sonc 2,000 profiles were snalyzed sspart of the 1979 fissionproduct survey. Page 8$ last paragraph says ~%ore precise data can be obtained. if the depth distribution is better knom.” Remend the dsta available be ussd to test the exponential hypothesis. 6. Page 8, paragrsph 2 and psge 9, pars”raph 1. Citd reference(4) as not* 7. Page 9, paragraph 3. The miniml detectable sctivlty (MDA) for Am 241 is 1 B (page 8, paragraph 2). Recomend the MDAbe reported for all 3 nuclides in Mth Wit$o TII~s might lnow sssessing ieportmce of h 24X to exposure rste an smsitfvity of in situ versus seil s~plfng for quantifying suburanic gmaa 8. Page 9, paragraph 3. MIA is claimed to vary from locstion to location but on page 10, pmragraph 3, it is claimed to be single-valued over the entire &toll. h%ich is correct? If the fomier is curmct, which seems reasonable, then xecomend r.e-evaluating data inlstble 4 @ discussion on page SO-II. 9. Psge 10, paragraph 3. DRI Ss indicated as determining ~ean concentrations .. - froa in situ data. Trmsuranic concentrations reported to the ~Gwete dcrivl d.ats~’based on ‘%ri~~ing.” me confident datg were used to guide cleanup actiol and deternine “c-~”tion~’ of each island. Areview of Table 4 indicates the nonconfident data is used in the draft dose study. Since confident data U* used to govern cleanup and cleanup iS to reduce dose, it would seen that the sme data should be used to predict dose. .Recorflend an explanation be given ls to why one set ofdats is used to clcanuplccrtify islands and another let $S used to estimate close. .- 10_ Tsble 4, ls cited on ptge 10. A $pot comparison of data in Table 4 tith that fomarded to CITG shows differences; e.g. “N” is 25 vs 24 for Clara lnd 71 vs 64 for Alice. I%t average AnJ241 for Kate is given as &09 pCi/g whereas the ERSP Tech Note show it to be 9.46 using confident deta and 8.17 using nonconfident data. Recomem? lny changes to data given CJTG be corrected and * check on arithmetic of Tables 2-4. AdditionaSJy, Peax - SS mitted lntbely from the study tnd data for Pearl was reported to ~Gs
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11. Page 11, parsgrsph”2. The exposu.re-to-$ose rate conversion factor . deserves explanation. For tx~le, does it produce tissue dose (gonadal), *e8-&iT gatma plus Cosnlc Ye... Thus, the explanation should give rationslc for devicting fros the approach used in WO-140 and on which the cltanup/rehabilitation is planned. The estimates using the proposed conversion fsctor~ill be *bout 30 percent lower thm given in NVO-140, ~is is a change which ctnnot 12. Page 14-1s. Resuspension studies to derive enhancement facters are p8t*graph 2, indicate that smple dats fox inhalation dose estimtes are introduces emors sinilar to using 0-1S cm soil sample data with Concentration Ratios based on 0-40 cmdata, and LLL has objected to this practice ls being Unacceptable. !tecommend discussion be ldded to erplsin @act of using enhtnce- -nt factors determined for onc soil depth with transuranic concentrstiens 1S. Page 1S, paragraph 3. Recemend explanation be given as to why data collected in Feb 77 and My 78 cm only be discussed as ‘~reliminary anaIYsi$” in Aug 79. The Cleanup EIS obligates DDE to=mduct & “co=pre~ensi~e air ==pling program over a period of 12 consecutive =onths... coticidcnt ~~th 34. Page 15, *’Drinking Water.” Tables”7-9s~ discussed only as they t81Me to drinking water but the tables cover ciomstic meat and chicken lggs. Recomnend additional discussion. Also, total d~ily intake of fluid specified l s one liter; this appears 10U: concentration in pork md chicken are the s- as in r-t EWCIC as reported in NVO-140. Table 9 is probably equivalent slthough the footnote uses “rat Sfi 4 of these rat tiuscles snd the avertge is 0.0J3 using Volune I Table 59 dstam 0.03S using Volume 111 data. (The difference is due to an error in tO 0.S1 pCifg is due to cleanup. On the other hand, ?WO-140 dose esticates MC not based on the rat mscle concentrations, but on l statistical correlation of radionuclides in soil lnd messerschaidia and scaevolsi leaves, a statistical correlation of the transfer coefficient for rat mscle and lea~ts~ snd an assumption that edible pork and chicken (domestic neat] aze equivalent to rat teat. Thus, clarify if the 0,S1 pWg is based on the correlation aPP~ ur the actual rat analyses. The correlation approach suffers, among other reasons, becsuse the dat~ tre not l’paired’r and they arc based on 0-1S CCI $0~1 $=ple dsta which m.ay not be tht SSBU as used in the present study.
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lggs sre equivalent to those in chicken (or -t meat or nesserscbidia Icaves). Reconncnd the xuthors zeview IAEA-SX-M9/6$ which report$ that Muptake by chickens is much greate~ athan $u uptake, that transuranic$ &re fomd primarily in the liver and that the only poztion of egg where they are found is the yolk. lle contribution to dose frcirn donestic ~tat is not lxplicit in the drsft study. lhwer, the Iirnited lnd questionable data enployed uould raise doubts about any predicted values. Reco~End additional discu$sien be added en uncertainty b radionuclide concentrations of pork, chicken and eggs. . 16. Page 16, last paragraph, The SOrn grid issho~ to include 0-S en .ssnples, in contrast to the in situ survey uhichreperted b 241 concentraticm for O-3 cm. %comend discussion be included conpsring the two sets of “surface data” lnd l clemr explanation of which dtta was ussd for each dose estitate p~thuay. It would appear that in situ is in situ is used for b 241 inhalation but soil ~le is ustd for Am 241 17. Page 17, paragraph 2. Soil samples ~re “screened.” Recomiend d~sc~ssion be included on sizt particles excluded, whether m not those pkrticles were washed of surface contamination, treatment of organic ~atter present} e?.G The discussion should coapare with EPA guidelines Mich specify transurmic concentration in soil uith size less than 2 ~. Also, since in situ..%es” W soil, and soil saaples “see” only the fracticm which passes the sereent de the two techniques produce different results? “ 28. Page 17, last paragraph. lkofile averages are elaiued to be based on Explain that ueights these increments zeceived. 19. P8ge 17, last paragraph. Discussion indicates dose estimates for imgestion 8re based on soil sample snalysis rather than in.situ analysis. Recomend lxplanstfon be givmfor selecting cme”set efdats in preference 20. Page S8, last paragrcph. Vague, If coconut trees hsve activity - ‘extending to 60 cm and soil samples were taken to 60 cm, then why not determine CRto 60CD depth? tither than be consistent, the reference vould seem to indicatt inccmsistency. More itqmtmtly, why use the sane depth for all plants? Some justifiezttion is needed on why squash zoots . draw nutrients fronthe sam depth as tree roots.
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25. l!rtadf~it and pandanus daily intakes uhertas the NVO-140 dose lstimates le Intakes of these item at Rongelap cnd UtsrLk total d87 g lccording to Table 2S. Dose froa these two items iS the ~fma~ reason thxt the Entwetak pople are guhled against any residence ~ bjebi in the EIS. (See AEC Task Group Repcmt Tables 1-4, ) If ths reduced intakes had been assmed in 1974, the people could have moved back to Enjcbi perhaps without ~ny cleanup. l%is factor clearly dtnonstratts the importance of diet as ststtd on page 49, paragraph 2. Moreover, it highli~hts the tmcert8inty in all estiutes. Recommend the lcpct of breadfruit and pandtnus intakes on dose estimates be highlighted in the study so that people who utilize the study will understand tht shaky foundation on which 23. Page iS, paragraph 2. Coconut consumption for Enewetak people is crgued that for a population uf 700, and trees pzoducing 100 nuts per year, the snmber of trees required for t subsistence of 0.S nuts/day is 1,277. In other words, the entire Atoll subsistence requirtmnts could be net by planting trees on the single isltnd of Vera tnd asy trees on other islands cwld strve for income (if the world market will purchase Enexetak coconut), till provide $100,000 intone, Thus, coconut tmc planting could be reduced by about one-half fros that mntioned in the EIS and the people KiIl meet their subsistence requirements as uell as receive more inco~e than originally you believe the IOK dose estiuates of this study, then you believe there is w need to plant excessive trees, or if you bel~tye rmre trees me needed, thcnyou $0 not believe the dose lstimates. are clatied to account for tiae on and coconuts frca isltnds Kate through Wilma; however, no datt is shorn for Pearl and Runit in Tsbles 2, 3, 4, 6. Raco~end expl=ation ef method for accounting for contributions from these two islands. Also, explain method for treating a group of islands, e.g, 2S. P+ge 30, parsgraph 1. Include in Table 27 the cctual reference man Ueights which are used to svoid confusion since btemational Commission On Radiation $rottction CICRP} 23 gives several weights under bone, lung, 26. P~ge 31, last pamgraph. Inplies that the old ICRP metsbolic are being used, New. ICRP 30calcuMions rmst be checked to see if vaSues change
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27. Page 32, paragraph “!nhtlation.” T%t stst~t of limited difference. neglects to lccount for exhtXation of xir. This2s confirmed b noting that ~ defines inhalation rate as product of respiration Tam (ZOEI /d for l of tht inhaled to the respiratory tract [30S toDL snd 70% to URT). For SO\ deposition in the DL, only 23f may deposit b the URT with the renaining =ke little difference in the dr~ft results sincc it SCCOUntSonly for the DL coqonmt. However, in view of the relatively large vslue (().~]) fOr fractional clearance from URT to blood, (which tbtn leads to dose to bone] neglect of URT clearance will lead to under-esttites of bone dose. Ifkii 241 is”ClsSS If, then the chicken study (Set cement sbvve) iS~DM9 iqotimt M the cmcentratien of soluble transuranic clenents in egg yolks is ach greater than insoluble. Mmeover, 1he transfer frsction used for ce=ply with EPA …
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