4 45 fable 6. Interlaboratory calibration of 239,2405, standard solution L.L.L. No. 1100, Hoff et al.(1973) and IAEA standards. rene en eae are 239, 2460p, Laboratory (apm/m1l) L.L.L. 1303 + 28 L.L.L. 1320 + 20 L.L.L. 1265 + M.C.L. 1255 +15 L.F.E. L.R.E. E.1.C. M.C.L. Mean Value Technique 5 Counting Standard Direct Assay Counter Efficiency 49.6% HE 241-Am Pulse Height Analysis 242Pu Environmental Standard Mass Spectrometry 242pu Mass Spec- trometry Standard Pulse Height Analysis 7?36pu standard 1330 + 27 1273 + 64 Pulse Height Analysis Pulse Height Analysis 236Pu 236Pu (H.A.S.L. Cali- 1207 + 54 Pulse Height Analysis 1272 + 6 Mass Spectrometry 242Pu Mass Spec- trometry Standard bration Standard) 236pu (LLL.L. Calibration Standard) (equal weights on all data) 1278 (Mean) (weighted) 414 1270 Error S.D. (Single Determination) Error S.D. S.D. (Single Determination) (Mean) S.D. Mean Value Reference Tracer £39 412 +4 Standards Recommended Value Sample No. Sample Type AG-I-1 Seaweed SD-B-1 Sediment * * 238pu (pCi/a) 3.8 +0.1 0.042 +.004 239,240py (pCi/q) 27.0% +0.1 0.96* +0.03 L.R.E. Value 238py (pCi/gq) 3.1** +0.1 N.D. Average of 18 different laboratory results. Average of four determinations. +240py (pCi/q) 23.4** +1.0 0.95* £.07