Document text
Machine-read from the scan, so expect some errors. Lines that couldn’t be read are left out.
Page 1
, ASSOCIATED UNIVERSITIES, INC.. U.S. Department of Energy The attached report presents the initial results of our personnel monitoring field trip to Enewetak and Ujelang. Please call me at FTS 666-4250, or Bob Miltenberger at FTS 666-2503 if you have any questions. With best regards, BNL Marshall Islands Radiological
Page 2
Results of the February 1980 Personnel Monitoring to Enewetak and Ujelang Atoll In February 1980 members of the BNL Marshall Islands Radiological Safety Program conducted a field trip to Japtan and Enewetak Islands, Enewetak Atoll and Ujelang Island, Ujelang Atoll. The purpose of this trip was to obtain baseline radionuclide body burden data on the Enewetak population prior to the repatriation of Enewetak Atoll Personnel monitoring was collection of 24 hour of urine Each person who was whole body with a one liter urine sample. accomplished through whole body counting and samples from all persons age 5 years and older. counted was asked to provide the survey team Past experience indicated that this represented the approximate urine output for 24 hours; and it was more productive to ask the subjects to submit a ‘“fullbottle” than to ask for a l’24 hour sample.” At Ujelang, old and infirmed persons who were not whole body counted were requested to provide urine samples. Participation in all aspects of the personnel monitoring program was voluntary. Bioassay samples were acidified with ten (10) grams of boric acid to retard biological degradation then sealed for shipment to Brookhaven National Laboratory. Upon receipt, the samples first will be analyzed spectrometrically for gamma emitters and then radiochemically for strontium and yttrium. Results from these analyses should be available prior to January 1, 1981. The total number of urine samples that were collected on this field trip is currently being determined. Our records indicate that 291 samples were collected at Ujelang Atoll, 33 at Japtan and 15 at Enewetak. More samples.:.. J which had not been collected at the time of our departure are expected from these last two islands. Reports from Holmes and Narvcr representatives at Enewetak Atoll indicate that they had been collected and acidified. The total shipment of urine samples was delivered to BNL on March 18, 1980. Whole body counting was conducted with two independent chair counting systems mounted in a large modified l’Matson” transportainer. In this counting geometry, an individual sits in a chair partially surrounded by two inches of lead shielding. A sodium iodide detector is positioned in front of the subject. The solid angle seen by the detector permits detection of photons emitted from all parts of an adult subject’s body between the neck and the knees. This ~ounting geometry allows the subject easy entry and egress from the whole body counter with minimal loss of system sensitivity relative to the bed geometry. Smaller subjects have more of their body within the solid angle while larger subjects have somewhat less. Figures 1 and 2 illustrate the counting geometry used and physical arrangement of one side of the whole body The chair body counters were calibrated for three geometries 1) an adult standard man, 2) an average Marshallese adolescent and 3) an average Marshallese juvenile. The population selected to determine the average height and weight of Marshallese adolescents and juveniles was the former Bikini Atoll population. Gamma spectra obtained at Enewetak Atoll and Ujelang Atoll were analyzed using the calibration standards which best matched the sex, height and weight of the individual subject. ..-/’ Table 1 summarizes the physiological and radiological data obtained from the February field trip. Statistical analysis performed on the mean CS-137
Page 3
body burden data from Japtan, Enewetak and Ujelang indicate that foK all population groups sampled (adolescent females excepted). The mean CS-137 body burden for Japtan residents is significantly lower than the corresponding mean for Ujelang residents at the 99% confidence level. The difference in the adolescent female mean body burden is significant at tlw 90% confidence limit. No comparison of mean adolescent male body burdens was made due to the spar city of data from Japtan Island. The mean adult male CS-137 body burden at Enewetak Is not significantly different from the mean adult male CS-137 body burden of Japtan but is significantly lower than the mean Ujelang adult male CS-137 body burden at the 99% confidence level. The CS-137 body burden data were examined statistically to determine the shape of the frequency distribution. Fit tests were attempted for linear, exponential and power functions, and no single shape perfectly describes all of the distributions represented by these data sets. It appears the data can be described equally well by normal or log-normal distributions. Quality control included replicate counts of subjects, and point source Cs-137/Cs-60 standard counts to determine the precision and accuracy of the new counting geometry. Duplicate sample results listed in Table 14 of Appendix A indicate the overall precision or reproducibility of the measurements are within 164 while the accuracy of the system, based on repetitive counting of a mixed point source is within 12X of the true value.
The text continues in the original scan (4 pages).