NEHA October 2022 Journal of Environmental Health

October 2022 • Journal of Environmental Health 11 targeted county from Equation 9 by simultaneously simulating 1,000 values from each of the probability densities p(θ), p(θ/z), and p(z/θ). A 95% credible interval for the mean number of children with BLLs of 5–9 µg/dL was estimated from the simulated values. An observed number of children with BLLs of 5–9 µg/dL in the targeted county was considered an acceptable number if within the boundaries of the credible interval for that county. The estimated mean number of children <6 years with BLLs of 5–9 µg/dL in the targeted county was recommended as the true value if the observed value was outside the boundaries of the credible interval. Results Tables 1, 2, and 3 show the observed numbers of White, non-White, and total children who had their BLLs tested and those children with BLLs of 5–9 µg/dL in the North, East, and South regions of Georgia. The 11 counties chosen in each of the regions, including West and Central regions (not shown in the tables), were next to each other. For our study, it was assumed that the BLL rates among children <6 years could be similar in each county because of their proximity to each other. County X in the last row of each table represents the targeted county where the proportion of children <6 years with BLLs of 5–9 µg/dL was found to be lowest among the 11 counties and the value of county X was estimated by the model. Tables 1, 2, and 3 (representing North, East, and South regions of Georgia, respectively) have slightly di“erent distributions of proportion of children with BLLs of 5–9 µg/ dL between White and non-White children. In the North region (Table 1), a smaller proportion of non-White children were tested for BLL in almost all the counties—and yet a higher percentage of them were found to have BLLs of 5–9 µg/dL. Thus, in county I in the North region, only 3 (0.07%) out of 415 White children tested had BLLs of 5–9 µg/dL, compared with 7 (2.15%) out of 325 nonWhite children tested. This finding is similar to that of county C in the North region: 1 (0.06%) out of 157 White children tested had BLLs of 5–9 µg/dL, compared with 2 (5.4%) out of 37 non-White children tested. In the East region (Table 2) and South region (Table 3), however, the situation was found to be completely the opposite. In both these regions, a smaller proportion of White children were tested, with a higher proportion of children with BLLs of 5–9 µg/dL in almost all the counties. Thus, in county A in the East region, 3 (23.08%) out of 13 White children had BLLs of 5–9 µg/dL, compared with 1 (3.84%) out of 26 non-White children. Similarly, in county A in the South region, 5 (8.77%) out of 57 White children tested had BLLs of 5–9 µg/dL, compared with 7 (1.00%) out of 70 non-White children tested. Tables 4, 5, and 6 show the predictive densities or estimated probabilities for 0–15 children <6 years with BLLs of 5–9 µg/dL in the targeted county for all, White, and nonWhite children, respectively. Each of these tables show probabilities for the five regions calculated based on Equation 9. According to Table 4, the estimated probabilities were found to be highest (0.190, 0.212, 0.181) at moderately three smaller numbers (2, 3, and 4, respectively) of all children <6 years with BLLs of 5–9 µg/dL in the targeted county in the North region. This finding indicates that the number of all children <6 years with BLLs of 5–9 µg/dL in the targeted county in the North region should be small, which is corroborated by its 95% credible interval [0.0, 9.3] shown in Table 7. Moreover, this Observed Blood Lead Levels (BLLs) for Children <6 Years From 11 Neighboring Counties in the South Region of Georgia, 2015 County a # of Children <6 Years # of Children <6 Years With BLLs of 5–9 µg/dL Total # of Children <6 Years Tested All White Non-White All White Non-White A 473 12 5 7 127 57 70 B 1,757 9 2 7 109 39 70 C 1,686 11 5 6 554 212 342 D 968 6 2 4 151 54 97 E 7,952 27 9 18 1,206 643 563 F 347 8 3 5 79 41 38 G 1,326 6 2 4 371 124 247 H 3,235 18 7 11 776 366 410 I 1,154 13 6 7 215 112 103 J 769 4 3 1 102 65 37 X b 2,910 15 4 11 990 519 471 a These 11 counties were chosen arbitrarily because they are contiguous. The assumption was that because they are contiguous, these counties will have similar BLL rates of 5–9 µg/dL among children <6 years. b X indicates the targeted county. A targeted county is one with the lowest observed proportion of tested children with BLLs of 5–9 µg/dL among children <6 years. TABLE 3

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