oi sj TABLE 22. __ M2 n/om?; ned from iu of 9M ¥ 1 produet > thorium ' i tron from 6 with an’ standards itron flux’ il of 9M. hat. mn perox:' d. These state and Age, years Sex Weight, g ash 22Th, ng/g ash Age, years Sex Weight, g ash 22Th, ng/g ash 3 3 U M 0.51 0.44 0.9 + 0.2 19+ 0.2 54 50 M M 0.72 0.64 14.8 + 0.4 20.2 + 0.3 il. 12 25 M F F 0.47 0.85 0.28 0.44 0.2 <0.1 12.2 + 1.9 9.9 + 0.5 60 62 64 65 M M M 41 F M F M 0.50 0.46 0.68 19+ 0.4 5.8 + 0.2 1.7 + 0.2 2.1 + 0.2 68 70 72 73 41 U 0.49 17+ 0.3 78 8 27 29 36 37 M M 0.26 0.74 0.61 <0.2 55 0.64 F 0.53 F M F M 0.59 0.46 0.48 0.75 22.3 + 0.6 3.4 + 0.4 3.4 + 0.3 M 0.68 22.4 + 0.4 42 43 M F 0.55 0.41 11+ 0.2 9.9 + 0.5 44 F 0.37 5.8 + 0.3 6.5 + 0.4 80 M 51 52 F F 0.30 7.5 + 0.6 a3 M 0.66 5.2 + 0.4 49 M 0.69 0.51 78 79 M 2940.2 9.2 + 0.8 14.1 + 0.7 13.1 + 0.5 4.1 + 0.2 13.1 + 0.5 F F 0.33 0.24 F 0.36 | 72.2 41,2 87 U 0.40 27.7 + 0.9 91 M 0.91 5.9 + 0.2 79 6.7 + 0.4 | 0.41 0.44 0.69 90 42.4 + 1.5 <0.2 0.50 F 4.0 + 0.4 0.46 30.5 + 0.8 we ple. This Th in Human Bone Asu a boiling the sam" dust. This individual operated a commercial movie olumn of projector where the carbon electrodes contain thoria ), 0.6 om* and ceria to improve the actinic quality of the light 50 both the! The variation of theTh concentration with age is shown in Figure 50. The simplest function to describe 20 mul-t the increasing concentration with age was assumed to v count-# squares be linear, and the solid line is that obtained by the as beent least squares analysis. The equation for this line is: _ by thet Y = (0.16 + 0.02)T (1) > in thet yn was? where Y¥ is the ?8*Th concentration in ng/g bone ash ul 7" is the age in years. | The distribution of the deviation from the least : stand-¢ 3 deter-| “quires line was skewed like that found for lead, J 5 | r 7 30/— b SF = > S 20/— - lol _ Inspection of Figure 50 will show that 14 results fall | Unusually close to the dashed line, having a slope ¥ = 0.057. This slope is one-third that of the solid ndivid-? line. The cause of this grouping is not known and will ¢ ‘quire additional information such as dust inhalatration; ti ‘h exposure and smoking histories. e high- 7 "he possibility of deter mining the retention of ividual; “Ra produced by the decay of 28°Th in bone was thoria * ‘vuluated. The maximum 282Th concen tration of 72 8 + | | + ° Oae , " ; count-é ounting | which was attributed to an increased level of exposure stand-? by smokers compared to non-smokers.A careful TF aol ash has been reported as 10 ng/g ash by Petrow and Approxi-! which the age is not given. These values agree well e second with the range of concentration found in this study. TTT . on prod-: source. 2 column The *?Th concentration in normal human bone ted with, Strehlow for a composite sample from individuals ted with whose ages were “largely adult.” In addition, Picer and *, which’ Strohal ) report 23 ng/g ash for a single sample for I 30 80 a0 “oe BO . agg | eo 8 AGE (YEARS) Fic. 50—Variation of thorium concentration in human bone ash with age. @, female; Mf male. ng/g ash was found in a 79-year-old woman wholived in Canton, [llinois, for 57 years. This city obtained water from deep sandstone aquifiers for many years.) Unfortunately, the wells were sealed so that samples could not be obtained. However, the