. et fa. attecal, All of the values reported by the contractor are corrected for a reagent biank. sco that the blank values reported here refiect the con- taminaticn of the filter material both during manufacture and Guring handling at HASL and at the contractor labcratory. Table l lists the results of the analyses of the blanks for each In general these data indicate low levels of contamination for mest of the nuclides, however it is significant to note tha ct nuclide. a] average Pu-238 biank rose from C.0C4 dpm in 1967 Becsuss the amount Of Pu-2383 found in quently in the to 9.22 dom in 1968. surface air sampies is fre-~ the range of 1 dom this blank may represent a significant fraction cf the total activity. The results of analyses on standard samples are shcwn in Table 2. These data are indicative of the accuracy cf the radiochemical anal- yses. The values shown are the average percert deviaticns between added activities and the results reported by the contracter. most of the results are satisfactory, there appezrs the Although to be a large pesi- tive bias in the Pu~-238 values fer much of 1968, which cannot be accounted for by the increase of the blank ccntamination. Samples sub=- mitted to the contractor during 1969 which were prepared with a new standard solution do not exhibit this bias, and it is therefore pre-= bable that the peor results reflect a degeneration cf the Pu-2338 stardard solution used for the preparation of the 1968 quality control samples. T - 10 .