MEASUREMENTS OF AIRBORNE RADIONUCLIDES 219 Table 6— CONCENTRATIONS OF 72Na AND *%4Nqa IN RAINWATER* Dis/min per liter Date Sample volume, liters June 15, 1964 60 4Na 22Na 0.70 + 0.138 0.36 + 0.03 June 17, 1964 6.64 2.22 + 0,25 0,25 + 0.04 June 18, 1964 14.32 0.59 + 0.09 0.19 + 0.02 *The plus or minus values are the standard deviations. Measurements of radionuclides such as these during the course of a rain would provide useful information for calculating rainout and washout coefficients of the normal atmospheric aerosols. BIOSPHERIC DISTRIBUTION OF 22Na Like BiCg “Na distributes itself through the biosphere, andit can be measured in many biological materials by direct counting of the sample ash on the multidimensional analyzer. Measurements of its distribution through the food chain and its calculated concentration in man based on bioassay measurements are given in Table 7. These data point out the usefulness of **Na as a tracer of weapons-testing debris. Table 7— DISTRIBUTION OF #2Na IN FOODS, BIOASSAY SAMPLES, AND MAN Sample Location Date obtained 22Na, dis/min per liter Western United States Elk Bass Quinault, Wash. Columbia River May 1964 April 1964 Beef Local food store, Washington March 1964 Milk Wheat Beef Washington Washington Local food store, Washington Corn Oregon Green beans Urine* Oregon Washington Lettuce Carrots Potatoes Mant March 1964 August 1963 May 1964 74,4 8.3 6.2 3.31 2.47 0.52 April 1964 ~0.04 April 1964 ~0.20 1.45 California California Idaho March 1964 April 1964 April 1964 Washington November 1963 0.16 ~0.07 0.68 39.57 (Table 7 continues on page 220)