What Do We Know of Childhood Exposures to Metals (Arsenic, Cadmium, Lead, and Mercury) in Emerging Market Countries?

Table 2

Summary of published studies reporting childhood exposures to (a) arsenic, (b) cadmium, (c) lead, and (d) mercury in Emerging Market countries.

(a)

Country	Ages	Specimen	Results*
Brazil	7–14 years	Urine	Median 3.60 versus 6.30, 6.40, 8.94 μg/L (unexposed versus 3 exposed groups) 𝑛=73 versus 𝑛=129, 107, 89 [38]
China	Newborn	Cord blood	Mean 3.82 μg/L, 𝑛=142 [39]
India	Children	Urine	Range 23–4030 μg/L, 𝑛=298 [40]
	9–11 years	Urine	Range 570–2349 μg/L, 𝑛=7 [41]
	5–15 years	Urine	Mean 78 μg/L (range 2–375), 𝑛=349 [42]
Mexico	4–6 years	Urine	Mean 143.9 versus 24.8 μg/L (exposed 𝑛=7 versus unexposed 𝑛=5) [43]
	6–8 years	Urine	Mean 58.1 μg/L, 𝑛=602 [44]
	6–11 years	Urine	Means 16.5 μg/dL [45], 19.9 μg/L [46], 𝑛=50, 90
	6–11 years	Urine	Medians 143.0, 100.0, 115.0 μg/L 𝑛=21, 22, 22 [47]
	6–11 years	Urine	Medians 136.75, 106.25, 116.0 μg/L 𝑛=19, 21, 20 [48]
	6–12 years	Urine	Mean 22.35 μg/g creatinine, 𝑛=229 [49]
Poland	8–12 years	Urine	GMean 7.98 versus 5.99 μg/g creatinine (𝑛=49 exposed versus 𝑛=50 unexposed females) [37]
			GMean 8.74 versus 6.73 μg/g creatinine (𝑛=44 exposed versus 𝑛=34 unexposed males) [37]

(b)

Country	Ages	Specimen	Results*
China	Newborn	Cord blood	Median 3.61 versus 1.25 μg/L (𝑛=289 e-waste exposed versus 𝑛=134 unexposed) [50]
			Mean 4.84 versus 2.81 μg/L (𝑛=289 e-waste exposed versus 𝑛=134 unexposed) [50]
	Newborn	Cord blood	Median 0.6 μg/L (range 0.02–1.78), 𝑛=109 [51]
	Newborn	Cord blood	GMean 0.36 μg/L (range 0.02–1.48), 𝑛=44 [52]
India	Newborn	Cord blood	GMean 0.6 μg/L, 𝑛=296 [53]
Mexico	6–11 years	Urine	Mean 4.7 μg/L, 𝑛=35 [45]
	6–12 years	Urine	GMean 0.78 μg/L, 𝑛=229 [49]
Poland	6-7 years	Whole blood	GMean 0.6 μg/L, 𝑛=183 [54]
	8–12 years	Whole blood	GMean 0.19 versus 0.08 μg/L (𝑛=50 exposed versus 𝑛=45 unexposed females) [37]
			GMean 0.19 versus 0.07 μg/L (𝑛=42 exposed versus 𝑛=35 unexposed males) [37]
	8–12 years	Urine	GMean 0.56 versus 0.45 μg/g creatinine (𝑛=49 exposed versus 50 unexposed females) [37]
			GMean 0.68 versus 0.44 μg/g creatinine (𝑛=44 exposed versus 35 unexposed males [37]
South Korea	4–10 years	Whole blood	GMean 1.51 μg/L (range 0.05–6.00), 𝑛=38 [55]
	4–10 years	Urine	GMean 1.33 μg/L (range 0.02–5.25), 𝑛=38 [55]
			GMean 1.69 μg/g creatinine (range 0.43–3.92), 𝑛=38 [55]
Taiwan	Newborn	Cord blood	Mean 0.67 μg/L, median 0.33 μg/L, 𝑛=402 [56]

(c)

Country	Ages	Specimen	Results
Brazil	6–8 years	Whole blood	Means 2.1 μg/dL [57], 5.5 μg/dL [58], 𝑛=444, 65
China	Newborn	Cord blood	Mean 4.06 μg/dL, 𝑛=240 [59]
	Newborn	Cord blood	Means 3.6 μg/dL [60], 11.33 μg/dL [61], 𝑛=110, 100
	Newborn	Cord blood	GMeans 5.35 versus 8.41 versus 6.0 μg/dL (urban 𝑛=24 versus rural 𝑛=45 versus industrial residence 𝑛=20) [62]
	Newborn	Cord blood	Median 4.36 μg/dL (range 1.72–9.82) 𝑛=109 [51]
	1–5 years	Whole blood	GMean 8.2 μg/dL, 𝑛=1117 [63]
	2 months–14 years	Whole blood	Means 16.38 versus 7.12 μg/dL (𝑛=369 polluted versus 𝑛=61 control area) [64]^†
	<6 years	Whole blood	GMean 4.71 μg/dL, 𝑛=44,048 [65]
	6–12 years	Whole blood	Range 1.59–31.8 μg/dL, 𝑛=317 [66]
	4–13 years	Whole blood	GMean 6.71 μg/dL, 𝑛=307 [67]
India	Newborn	Cord blood	GMean 5.1 μg/dL, 𝑛=296 [53]
	Newborn	Cord blood	Means 11.4 versus 16.02 μg/dL, 𝑛=23 normal weight versus 𝑛=24 growth retarded [68]
	Infants	Whole blood	Mean 10.15 μg/dL (range 0.046–42.94), 𝑛=200 [69]
	3–7 years	Whole blood	Mean 11.47 μg/dL (range 2.6–40.5), 𝑛=756 [70]
	3–12 years	Whole blood	Mean 4.23 versus 9.86 μg/dL (𝑛=51 controls versus 𝑛=17 aplastic anemia cases) [71]
	5–13 years	Whole blood	Mean 15.11 μg/dL, 𝑛=100 [72]
	15–18 years	Whole blood	Mean 9.96 μg/dL (range 4.62–18.64), 𝑛=39 [73]
Indonesia	6–12 years	Whole blood	GMean 8.6 μg/dL (𝑛=397) [74]
Mexico	Newborn	Cord blood	Means, 2.7 μg/dL [75], 6.2 μg/dL [76], 8.1 μg/dL [77], 6.6 μg/dL [78], 6.7 μg/dL [79], 6.6 μg/dL [80], 5.49 μg/dL [81], 𝑛=226, 146, 617, 424, 197, 364, 294
	1 month	Whole blood	Mean 5.5 μg/dL (range 1–23.1), 𝑛=222 [82]
	12 month	Whole blood	Means 4.6 μg/dL [81], 7.2 μg/dL [79], 𝑛=294,197
	1 year	Whole blood	GMean 8.4 μg/dL, 𝑛=302 [83]
	2 years	Whole blood	GMean 10.1 μg/dL, 𝑛=264 [83]
	2 years	Whole blood	Means 4.8 μg/dL [76], 5.78 μg/dL [81], 8.2 μg/dL [80], 8.4 μg/dL [79], 𝑛=146, 752, 283, 179
	3 years	Whole blood	Mean 8.4 μg/dL, 𝑛=206 [80]
	4 years	Whole blood	Mean 8.2 μg/dL, 𝑛=227 [80]
	6–8 years	Whole blood	Median 10.2 μg/dL (range 1.9–43.8) 𝑛=598 [84]
	6–8 years	Whole blood	Mean 11.5 μg/dL, 𝑛=21 [44]
	6–11 years	Whole blood	Means 4.6 μg/dL [45], 9.4 μg/dL [49], 𝑛=229, 50
	6–11 years	Whole blood	Median by group, with increasing proximity to source: 4.6, 9.5, 28.6 μg/dL, 𝑛=21, 22, 22 [48]
	6–11 years	Whole blood	Median by group with increasing proximity to source: 7.02, 20.6, 30.38 μg/dL, 𝑛=21,21,23 [47]
	6–12 years	Whole blood	GMeans 10.5, 11.2, 12.4 μg/dL, 𝑛=12,22,24 [85]
Poland	Newborn	Cord blood	Median 1.23 μg/dL (range 0.44–6.90), 𝑛=444 [86]
	Newborn	Cord blood	Mean 1.42 μg/dL, 𝑛=452 [87]
	5–14 years	Whole blood	Mean 7.69 μg/dL, median 6.77 μg/dL (range 2.7–23), 𝑛=74 [88]
	6-7 years	Whole blood	GMean 4.2 μg/dL, 𝑛=202 [54]
	7–15 years	Whole blood	Mean 7.3 μg/dL, median 6.6 μg/dL, 𝑛=272 [89]^†
	8–12 years	Whole blood	GMean 5.72 versus 3.42 μg/dL (𝑛=47 exposed versus 𝑛=50 unexposed females) [37]
			GMean 6.51 versus 3.81 μg/dL (𝑛=42 exposed versus 𝑛=35 unexposed males) [37]
South Korea	4–10 years	Whole blood	GMean 3.80 μg/dL (range 1.30–9.95) 𝑛=38 [55]
	10–15 years	Whole blood	Mean 4.3 versus 6.9 μg/dL (𝑛=167 controls versus 𝑛=39 anemia) [90]
Taiwan	Newborn	Cord blood	Means 7.8 versus 3.28 versus 2.35 μg/dL in 1985–87 versus 1990–92 versus 2001-02 [91]
	Newborn	Cord blood	Mean 1.29 μg/dL, 𝑛=308 [92]
	Newborn	Cord blood	GMeans 1.26 μg/dL [93], 1.30 μg/dL [94], 𝑛=1526, 430
	2-3 years	Whole blood	GMean 2.48 μg/dL, 𝑛=430 [94]
	5-6 years	Whole blood	GMean 2.49 μg/dL, 𝑛=430 [94]
	8-9 years	Whole blood	GMean 1.97 μg/dL, 𝑛=430 [94]
	7–11 years	Whole blood	Means 1.60 versus 7.79 μg/dL (𝑛=71 controls versus 𝑛=79 exposed males) [95]
	8–12 years	Whole blood	Means 3.45 versus 5.23 versus 8.80 μg/dL, 𝑛=100 unexposed versus 𝑛=30 and 34 exposed [96]
Turkey	Newborn	Cord blood	Mean 1.65 μg/dL, 𝑛=120 [97]
		Whole blood	Mean 3.56 μg/dL, 𝑛=180 [97]
	15–19 years	Whole blood	Mean 7.8 versus 1.6 μg/dL (𝑛=79 exposed versus 𝑛=71 unexposed) [98]

(d)

Country	Ages	Specimen	Results
Brazil	Newborn	Cord blood	GMean 9.63 μg/L, 𝑛=61 [99]
	Newborn	Cord blood	Mean 16.68 μg/L (range 0.35–135.04), 𝑛=1510 [100]
China	Newborn	Cord blood	GMean 5.58 μg/L, 𝑛=384 [101]
	Newborn	Cord blood	Mean 7.0 μg/L (range 2.28–39.72), 𝑛=110 [60]
Indonesia	9–17 years	Urine	Medians 0.32 versus 7.06 μg/g creatinine (control 𝑛=50 versus occupationally exposed 𝑛=80) [102]
		Whole blood	Medians 3.47 versus 7.75 μg/L (control 𝑛=50 versus occupationally exposed 𝑛=80) [102]
Mexico	6–11 yr	Urine	GMean 4.2 μg/g creatinine, 𝑛=23 [103]
	6–12 yr	Urine	Mean 0.7 μg/L, 𝑛=50 [45]
Poland	Newborn	Cord blood	Mean 1.06 μg/L, 𝑛=313 [104]
	Newborn	Cord blood	GMean 0.88 μg/L (range 0.10–5.00) 𝑛=233 [105]

*Results are expressed as they were provided: arithmetic mean (mean), geometric mean (Gmean), or median value.
^†Study of occupational take-home exposure.