Exposure profile of mercury, lead, cadmium, arsenic, antimony, copper, selenium and zinc in maternal blood, cord blood and placenta: the Tohoku Study of Child Development in Japan

Table 2 Exposure levels of toxic and essential trace elements in the maternal blood, cord blood and placenta

	Elements	N	Median	25th–75th percentile	Min	Max	< LOD^b (%)
Maternal blood (ng mL⁻¹)	As	649	4.06	2.68–6.81	< 0.30^b	17.64	2.3
	Bi	649	0.02^b	0.02^b–0.02^b	< 0.02^b	2.51	92.6
	Cd	649	1.18	0.74–1.79	< 0.10^b	11.23	5.4
	Cu	649	1289.2	1155.9–1449.1	501.5	2677.5	0
	Pb	649	10.83	8.65–13.50	3.10	70.24	0
	Sb	649	0.20	0.06^b–0.40	< 0.06^b	7.99	31.4
	Se	649	176.4	155.1–196.7	93.3	416.3	0
	Sn	649	0.20^b	0.20^b–0.38	< 0.20^b	7.95	55.6
	THg^a	650	5.42	3.89–7.59	0.61	25.19	0
	MeHg^a	645	5.15	3.68–7.15	0.60	24.99	0
	IHg^a	645	0.24	0.09–0.43	< 0.01	1.61
	Zn	649	4769.0	4146.7–5417.8	2707.2	14,416.6	0
Cord blood (ng mL⁻¹)	As	594	3.68	2.58–5.25	< 0.30^b	22.41	0.5
	Bi	594	0.02^b	0.02^b–0.02^b	< 0.02^b	1.87	82.0
	Cd	594	0.53	0.10^b–1.25	< 0.10^b	10.52	26.4
	Cu	594	510.8	456.2–566.5	243.5	1429.8	0
	Pb	594	9.89	8.02–12.48	3.66	61.61	0
	Sb	594	0.39	0.06^b–0.92	< 0.06^b	6.40	28.3
	Se	594	191.4	166.5–219.0	73.9	376.2	0
	Sn	594	0.20^b	0.20^b–0.38	< 0.20^b	5.23	63.6
	THg^a	601	9.96	7.05–13.80	1.60	43.90	0
	MeHg^a	598	9.47	6.70–13.28	1.52	43.15	0
	IHg^a	598	0.27	0.10–0.63	< 0.01	2.43
	Zn	594	2002.9	1757.7–2352.2	1103.9	22,258.6	0
Placenta (ng g-wet^-1)	As	617	4.36	3.26–5.93	1.18	19.56	0
	Bi	617	0.03^b	0.03^b–0.04	< 0.03^b	1.35	72.6
	Cd	617	16.95	12.97–22.72	3.52	51.49	0
	Cu	617	706.5	627.1–806.5	442.9	1419.3	0
	Pb	617	11.21	7.67–15.55	2.14	125.00	0
	Sb	617	0.24	0.10^b–0.56	< 0.10^b	33.43	37.8
	Se	617	295.3	265.0–331.9	172.4	503.5	0
	Sn	617	11.83	6.55–19.43	< 0.30^b	197.56	1.9
	THg	617	12.60	9.31–16.47	1.98	52.44	0
	Zn	617	9101.4	8353.3–9917.1	6771.8	17,381.8	0

Copper, selenium and zinc concentrations were presented up to one decimal digit because of high concentration compared with other elemental concentrations
As arsenic, Bi bismuth, Cd cadmium, Cu copper, Pb lead, Sb antimony, Se selenium, Sn tin, THg total mercury, MeHg methylmercury, IHg inorganic mercury (IHg concentrations were calculated by subtracting MeHg from THg), Zn zinc
^ang g⁻¹
^bLimit of detection (LOD)

ISSN: 1347-4715