— , . 1 Be eh dee Ea BS Dbaead eee nawha alee SatiacctRette. Project Airstream The Health and Safety Laboratory measures radioactivity in the lower stratosphere employing the RB-57F aircraft as a sampling platform. The aircraft are flown by the 58th Weather Reconnaissance Squadron under the direction of the 9th Weather Wing of the Air Weather Service. The missions are scheduled for early Feb- ruary, May, August and November and the coverage extends from 75°N to 51°S latitude in the Western Hemisphere, Air filter sam- ples are collected from 12 to 19 km altitude and analyzed for ten radionuclides. A more complete description of the program and avallable data are given On pages II-9 to II-67. High Altitude Balloon Sampling Program Balloon borne filtering devices are used to collect nuclear debris at altitudes from 24-41 km. Balloon launchings are conducted quarterly at Fairbanks, Alaska, 65°N; San Angelo, Texas, 31°N; Panama C.Z., 9°N; and Mildura, Australia, 34°S. Filters are analyzed for ten radionuclides. A more complete description of the program and available data were presented in HASL-217 cn pages II-148 to II-206. Corrected sampling dates for three samples are given in this report beginning on page II-68. Radiostrontium in Milk ns dny 1s ir Strontium?9 levels in both powdered and fresh milk distributed in New York City and tap Water sampled at the Health and Safety Laboratory, have been measured on a monthly basis since 1954. These data are summarized in tabular and graphical form in the Appendix, Section E. Strontium?° in Diets Quarterly estimates of the annual dietary intake of sr29° of New York City, Chicago, and San Francisco residents have been made based on analyses of foods purchased at these three cities every three months since 1960. Sampling in Chicago has been discontinued. The program is described and available data reported on p. II-4 to II-6 of this report. UNSCEAR ~- WHO Bone ind ind and Tap Water Program Available Sr99 data for human bone samples collected in 1969 from countries in Latin America and Africa are presented on pages II-7 and II-8 of this report. II - 3 — -