Table 5. Radionuclides measured radiochemically except as noted. Values or in soil standard samples. Al! analyses done Radionuclide (pCi/kg) laboratory 905, I 375 239+240p,,, 241 am WOSC, OSU? EMLP 88.74 4.1% (3) LLNLS -- 35.8 + 3.8% (8) 36.9 43.7% (3) -- 36.4 + 5.4% (10) 3468 + 9.8% (3) 37.4 + 0.6% (2) 15.5 + 7.2% (4) 14 4.7% (3) _ Certified 36 + 10% 36 + 10% 16+ 10% 89 + 10% NOTE: Numbersof replicates are in parentheses. @ Western Oregon State College, Oregon State University. Environmental Measurements Laboratory. © Measured by gamma-ray spectrometry. d Lawrence Livermore National Laboratory. intercalibration exercise, the measurements were well corroborated. These known additions of radioactivity were used to establish the expected radioactivity. Second, all the standards except the terrestrial animal standard were analyzed radiochemically. The results of these analyses are shown in Tables 4-6. The laboratories at WOSC and Oregon State University (OSU) have collaborated for several years and their results are combined. Corroborating analyses were performed by EML and LLNL. The radiochemical! methods at WOSC and OSU have been demonstrated for the measurement of 1376, 23942405. and 241 Am (see Ref. 4), and the measurements of those three radionuclides were taken as the certified values. Because the WOSC, OSU measurement of 705, had not been demonstrated, we used the analyses of EML to certify the 905. As Tables 4-6 show, excellent agreement was found for all radionuclides. In Table 7 we present only the expected values for the terrestrial animal standard because it was prepared by the same method as the vegetation and marine organism standards by adding known amounts of the radionuclides. Consequently, no radiochemical analyses were required. We are confident that the certified activities, or expected values in the case of the terrestrial animal standard, are correct within the tolerance quoted in Tables 4-7. This has been further laboratories. STREETTRIENaas Lene Fee demonstrated by the high degree of compliance by two of the three participating