434 JOURNAL OF THE 4.0.4.C. (Vol. 42, No. 2, 1959) Table 3. Average total beta radioactivity of miscellaneous foodstuffs produced before and after 1945 Foodstuff Wheat? Sugar and jams? Meat products Bread? Cocoa beans? Misc. sea food* Coffee4 No. Before 1945 /m/g s.e.(+) No, 28 17 13 13 16 12 8 19 21 13 0.00 0.00 0.19 0.151 0.049 0.111 16 0.00 0.130 From 1945 to 1957 inel. /m/2 g.e,(-) 0.01 0.03 0.00 0.00 0.33 G.00 0.00 0.087 0.005 0.125 0.119 0.234 0.196 0.874 ® The unprocessed wheat grain. . > Includes sirup and a variety of fruit jama. «Includes beef, pork, poultry, lamb: also dried and cured products. 4 Fresh: All 1957; no pre-1945 samples available. * Includes shrimp, crab, lobster. post-1945 over the pre-1945 samples is dem- onstrated. Again it was noted from the raw data that the preponderance of samples was drawn from the years 1945 to 1950. Taking the 107 samples originating from the year 1945 and comparing with 46 samples from the years 1956 and 1957, the averages are as follows: 1945, 0.05 d/m/g; and 1956 and 1957, 0.00 d/m/g. There is no trend toward increased radioactivity in current samples. Unfortunately, only a very limited number of vegetables are represented by the leafy variety, such as cabbage and lettuce; therefore, in the light of recent findings (3) further analyses must be conducted to confirm present trends (1948 et seq.). Table 3 lists results for a number of miscellaneous foodstuffs. No significant increase in radioactivity is demonstrated for wheat, sugar and jams, meat products, and miscellaneous sea foods. No pre-1945 samples of bread, cocoa beans, and coffee were obtainable; henee a comparison is not possible. However, unless cocoa beans store some other natural radioactive substance, it is possible that this product reflects contamination from fallout. Further work is necessary. With respect to wheat which has been shown to be radioactive in certain areas of Minnesota in the growing years of 1956, 1957, and 1958, it should be emphasized that prac- tically all our post-1945 samples came from the 1956 harvest. Of these, 16 samples originated from California, 3 from Texas, 2 from New York, and one each from Indiana and Michigan. This may account, therefore, for our non-confirmation of increased contamination in this product to date. The products which have shownsignificant increases in radioactivity, or at least well defined trends, are shown in Table 4. Of these, the dairy products show a highly sig- nificant increase in total radioactivity in the post-1945 period. Tea shows an outstanding increase. When plotted by years, the indi- vidual values for the dairy products described a line having a significant positive regression. A similar plot for shellfish is shown in Fig. 1. Identification studies on two samples of tuna fish which exhibited marked elevation in total radioactivity showed that the principal nuclide was zinc 65. Two samples of tea, similarly studied, revealed the presence of significant amounts of zirconium 95. These analyses were made by gamma spectrometry (4). Two samples of tea showingrelatively high total beta counts were subjected to radiochemical analyses (5). Of the total beta radioactivity in one sample, 6.7% and 45% was accounted for, respectively, by total Table 4. Foodstuffs which have shown increased total radioactivity when compared with pre-1945 samples Foodstuff Fish¢ Shellfish¢ Dairy products‘ Tea? * 6 ¢ 4 Before 1945 No, /m/zg From 1945 to 1957 incl, No. d/m/g 25 15 0.00 0.00 26 32 0.322 0.364 36 0.00 &8 31.4 26 0.00 46 Includes mainly salmon, sardines, and tuna fish, Significance level, p = 0.1. Includes oysters, clams, and mussels. Significance level, p = 0.1. ‘Includes fluid, dry milk, cheese, f Significance level, p = 0.01. ? Tea leaves only, not the beverage. 0.55/