ALTE. Lt in Table 1). O. PaakKoua, R. NASANEN, D. Merten and J. K. Miettinen, Strontium 90 11 in the autumn (Nos. 12 and 13) but the difference is probably not significant. The sameis true regarding the difference between the spring (= May and J] He HE He HEHEHE He HE HE HE HE June) values of the factories »A» (Nos. 10 and 11) and »B» (Nos, 14 and 15). e ™Sr/g Ca ; obtamed, It is of interest to note that a milk powder sample from Somero (factory B) taken in Sept. 1957 and analysed by the method of Bryante¢ al. (15) by one of us (D.M.), gave 7.0 wuc Sr/g of Ca. The Sr content of the milk samples from the experimental farms varies from 3.6 to 11.6, the mean being 5.7 zuc Sr/g Ca. This is significantly lower than the corresponding »country-wide» value for Southeast Finland, 8.0 uue %S8r/g Ca (No. 12, August 15). This may be partly due, for instance, to the fact that the productivity of the pastures of the experimental farms is considerably better than the average. The higher value of sample 9, 11.6 yuyc %Sr/¢ Ca, may correspondingly be due to the very poor soil and low productivity of the natural wet lake-coast pasture in question. This value is significantly higher than the other value from Lapland (No. 1), 3.7 gue 9Sr/¢ Ca, but not much higher than the corresponding »wide-area» value for Southeast Finland, 8.0 nuc Sr/g Ca. Milk produced in farms with poor pastures in South Finland would probably show similar activities, because the average (8.0 wuc Sr/g Ca) is much higher than the mean of »good» (= experimental) farms, 5.7 suc “WSr/g Ca, (Nos. 1—8). jes reported yin Tables ae activity »A» (Nas, - ples taken The Sr content of the grass sample No. 9 (Table 3) is also about twice as high as the mean ofall farms. Otherwise it is not possible on the basis of the present study to say with certainty whether the relatively small differences between the individual farms are due to the difference in rainfall or in soil conditions or to other factors. The average value for the milk of South Finland in summer 1959, 8.7 upe °Sr/g Ca, is of the same order as values for Great Britain in 1959, 9.35 ue “Sr/g Ca, (7), for Sweden in December 1957, 7.8 wuc Sr/g Ca, (16), for Germanyin April to December 1959, 8.6 wuc Sr/g Ca, (19). It is slightly lower than the mean value for Norway in 1958, 11.4 puc Sr/e Ca, but significantly lower than the corresponding Norwegian value for the first months of 1959, 17.4 ue Sr/g Ca (11), and the Canadian values for summer 1959, ca. 20 puc Sr/g Ca (20). Since the 1959 values for the other countries are evidently also higher than the 1958 values quoted above and since our values, reported in this paper, are representative of summer conditions, when the Sr content of milk reaches the annual maximum (9, 11), it can be concluded that the %Sr content of milk in South Finland is slightly lower than in the other countries in Northern and Western Europe. The value obtained in the present study for the discrimination factor grass-milk, 0.048, is significantly lower than that quoted in the UN Report (1), 0.16, or reported by

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