MercuNorth – monitoring mercury in pregnant women from the Arctic as a baseline to assess the effectiveness of the Minamata Convention

Figures & data

Table 1. MercuNorth study details and participant characteristics

Study Location(s)	Year(s)	Sample Size	Study Population	Mean Age (Range)
Participants from a total of 57 communities in the Yukon-Kuskokwim region, Alaska, USA;	2010-2012	n=152	Yupik Mothers^1	26.5
Participants from 14 communities in Nunavik, Québec, Canada;	2013	n=95	Inuit pregnant women^2	24.2
			(1st Trimester Pregnancy)	(18-41)
Participants from 15 communities in Greenland;	2010-2013	n=196	Inuit pregnant women^3	27.5
			(Primarily 2nd (57%) and 3rd (36%) trimester)	(18-44)
Reykjavik, Iceland;	2014-2015	n=50	Icelandic pregnant women (3rd trimester)	31.3
				(22-43)
Bodø, Norway	2014-2015	n=50	Norwegian pregnant women (2nd trimester)	31.5
				(21-40)
Kiruna, Sweden	2015-2016	n=51	Swedish pregnant women (3rd trimester in week 28–29)	28.6
				(20-42)
Inari, Northern Lapland, Finland;	2014	n=25	Finnish pregnant women^4 (from all trimesters between week 9-37)	30.2
				(21-39)
Nickel City, Pechenga district, Murmansk Oblast, Russia	2013-2014	n=50	Russian pregnant women^5 (3rd trimester)	29
				(20-42)

¹Recruited at first prenatal visit as part of the Alaskan Native MOM study (Mosites et al., 2020).

²Recruited from the Arctic char program (Dewailly, 2013).

³Recruited from the ACCEPT Birth Cohort (Bank-Nielsen et al., 2019).

⁴Recruited from the KolArctic study.

⁵Recruited from the KolArctic study (Dudarev et al., 2016); Two participants were not ethnic Russians.

Table 2. Blood Hg concentrations in pregnant women by study regions from 2010 to 2016

Study regions	Sample size (n)	Blood Hg concentrations (µg/L)							% ≥5 µg/L HBM I^a	% ≥5.8 µg/L Guidance value^b	% ≥8 µg/L Guidance value^c
		GM (range)	Percentiles [95% CI]
			10th	25th	50th	75th	90th	95th
Alaska	152	2.13 (0.28–9.71)	0.82 [0.65–0.98]	1.23 [0.97–1.49]	2.36 [1.98–2.74]	3.45 [3.08–3.81]	5.18 [4.37–5.99]	6.25 [4.47–8.04]	11.8	6.58	2.63
Nunavik	95	5.2 (0.28–32.1)	1.33 [0.41–2.26]	3.32 [2.31–4.33]	5.88 [4.74–7.02]	9.67 [8.26–11.08]	12.47 [10.75–14.20]	14.03 [5.56–22.50]	63.2	42.1	37.9
Greenland	196	3.79 (0.02–73.01)	1.10 [0.73–1.48]	2.06 [1.71–2.41]	4.20 [3.57–4.83]	7.15 [5.61–8.69]	11.75 [10.35–13.15]	15.21 [11.21–19.21]	40.8	35.2	23
Iceland	50	1.29 (0.14–3.61)	0.50 [0.15–0.86]	0.99 [0.66–1.32]	1.38 [1.11–1.65]	2.00 [1.64–2.35]	2.41 [1.95–2.86]	2.71 [2.05–3.36]	0	0	0
Norway	50	1.2 (0.20–3.41)	0.45 [0.25–0.65]	0.81 [0.60–1.02]	1.20 [0.83–1.57]	1.94 [1.67–2.20]	2.31 [1.91–2.70]	2.61 [1.93–3.28]	0	0	0
Sweden	51	0.48 (0.20–1.89)	0.20 [0.13–0.27]	0.20 [0.13–0.27]	0.39 [0.32–0.46]	0.75 [0.55–0.95]	1.13 [0.76–1.49]	1.49 [–]	0	0	0
Finland	25	0.71 (0.05–3.81)	0.10 [–]	0.37 [0.00–0.76]	0.93 [0.49–1.38]	1.41 [0.81–2.01]	2.13 [0.92–3.33]	2.81 [–]	0	0	0
Russia	50	1.08 (0.30–3.99)	0.55 [0.39–0.71]	0.75 [0.65–0.86]	0.95 [0.75–1.15]	1.56 [1.11–2.00]	2.39 [1.42–3.36]	3.13 [–]	0	0	0

^aHuman biomonitoring value I [22].

^bBlood equivalent of US EPA reference dose [32].

^cHealth Canada Provisional blood MeHg guidance value [20].

Data presented in whole blood (µg/L) as geometric means (range), and by percentiles [95% CI]. Pregnant women over exceedance values presented as percentages (%).

Figure 1. Distribution of blood Hg concentrations in participants from each study region

Table 3. Pairwise comparison of geometric means between study regions (p-values)

Study regions	Pairwise Comparisons between regions (p-value^a)
	Nunavik	Greenland	Iceland	Norway	Sweden	Finland	Russia
Alaska	<0.0001	<0.0001	0.0003	<.00001	<0.0001	<0.0001	<0.0001
Nunavik		0.0030	<0.0001	<0.0001	<0.0001	<0.0001	<0.0001
Greenland			<0.0001	<0.0001	<0.0001	<0.0001	<0.0001
Iceland				0.6768	<0.0001	0.0046	0.2997
Norway					<0.0001	0.0126	0.5350
Sweden						0.0569	<0.0001
Finland							0.0466

^aANOVA overall F-test: p<0.0001, 7 degrees of freedom.

Figure 2. Temporal trend of geometric mean Hg concentrations (μg/L) in whole blood of pregnant women from Nunavik, (1992–2013), Alaska (2000–2012) and Greenland (2010–2015). Error bars represent the GM 95% confidence interval

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