Clinical Pharmacist and Master’s student in Clinical Pharmacy with research interests in pharmacovigilance, behavioral interventions in mental health, and AI applications in clinical decision support. Experience includes digital health research with Bloomsbury Health (London) and pharmacovigilance practice in patient support programs. Published work covers drug awareness among healthcare providers, postpartum depression management, and patient safety reporting. 
Clinical Pharmacist and Master’s student in Clinical Pharmacy with research interests in pharmacovigilance, behavioral interventions in mental health, and AI applications in clinical decision support. Experience includes digital health research with Bloomsbury Health (London) and pharmacovigilance practice in patient support programs. Published work covers drug awareness among healthcare providers, postpartum depression management, and patient safety reporting. What was studied?
The MercuNorth study systematically investigated mercury exposure in pregnant women across the circumpolar Arctic. Motivated by the known health risks of methylmercury—especially its irreversible neurodevelopmental effects on fetuses—the research aimed to establish a baseline for blood mercury levels prior to the full implementation of the Minamata Convention on Mercury in 2017. The study collected whole blood samples from 669 pregnant women between 2010 and 2016, spanning eight Arctic regions: Alaska (USA), Nunavik (Canada), Greenland, Iceland, Norway, Sweden, Northern Lapland (Finland), and Murmansk Oblast (Russia). Blood mercury was quantified using inductively coupled plasma mass spectrometry (ICP-MS), with rigorous internal and interlaboratory quality controls to ensure data comparability. The research also conducted temporal trend analyses in regions with historical data to assess changes in mercury exposure over decades. The core purpose was to provide a multi-regional snapshot of mercury exposure in a highly vulnerable population—pregnant women—thereby enabling future evaluation of the Minamata Convention’s effectiveness in reducing human mercury burdens, particularly in communities reliant on traditional marine foods.
Who was studied?
The study population comprised 669 pregnant women aged 18–44 years, with a mean age around 28 years, drawn from both Indigenous and non-Indigenous communities across the circumpolar Arctic. The sample included 152 Yupik mothers from Alaska, 95 Inuit women from Nunavik, 196 Inuit women from Greenland, and smaller groups from Iceland, Norway, Sweden, Finland, and Russia. Recruitment methods varied by country but were all voluntary and based on convenience sampling, often as subsets of broader health or cohort studies. Notably, the highest-risk groups—in Alaska, Nunavik, and Greenland—were Indigenous women with traditional diets high in fish and marine mammals, key sources of dietary methylmercury. Other regions primarily included non-Indigenous women with more varied, often less marine-centric diets. Ethical oversight was maintained in each country, and all participants provided informed consent. While the sample was not designed to be fully representative of all Arctic pregnant women, it encapsulated diverse dietary patterns, environmental exposures, and community contexts relevant to mercury risk assessments and regulatory monitoring.
Most important findings
| Critical Points | Details |
|---|---|
| Baseline blood mercury (Hg) levels varied markedly by region. | Geometric mean (GM) blood Hg was highest in Nunavik (5.20 µg/L) and Greenland (3.79 µg/L), followed by Alaska (2.13 µg/L). All other regions had much lower concentrations, ranging from 0.48 to 1.29 µg/L. These differences reflect distinct dietary practices, especially traditional diets rich in marine mammals and fish, which are primary sources of methylmercury in the Arctic. |
| Exceedances of health-based guidance values concentrated in Indigenous regions. | A significant proportion of pregnant women exceeded international blood Hg guidance values in Nunavik (37.9% ≥8 µg/L), Greenland (23%), and Alaska (3%). In contrast, all other regions (Iceland, Norway, Sweden, Finland, Russia) had no women exceeding these thresholds, underscoring the importance of dietary exposure from traditional foods in Indigenous Arctic communities. |
| Significant downward trends in blood Hg levels over time in key regions. | Time trend analyses revealed substantial annual decreases in blood Hg: Alaska (−7.5% per year, 2000–2012), Nunavik (−4.7% per year, 1992–2013), and Greenland (−2.7% per year, 2010–2015). These declines are likely due to reduced consumption of high-Hg marine mammals and a dietary shift towards market foods, rather than reductions in global mercury emissions. Correspondingly, fewer women now exceed blood Hg guidance values than in previous decades. |
| Regional and intra-regional variability influenced by dietary habits. | Within-region differences were notable, especially in Greenland, where coastal communities and those with higher marine mammal intake had higher blood Hg. Local dietary patterns, particularly seasonal consumption of species like beluga, lake trout, and seal liver, strongly determined individual exposure levels. Regions with less reliance on marine mammals, and more on fish or market foods, showed consistently lower Hg levels. |
| Methodological rigor supports data reliability for certification purposes. | The study employed standardized blood collection, validated analytical techniques (ICP-MS), and extensive quality control (internal, external, and interlaboratory programs). This methodological robustness ensures that the findings are both comparable across regions and suitable as a baseline for ongoing certification and regulatory monitoring under programs like HTMC. |
| Limitations highlight areas for improvement in future biomonitoring. | The study only measured total mercury (not distinguishing methylmercury vs. inorganic forms) and lacked comprehensive dietary data, which limits interpretation of exposure sources. Sample sizes were small in some regions, and convenience sampling may affect representativeness. These gaps suggest that future certification efforts should include mercury speciation and integrate dietary assessments to refine risk evaluation and regulatory responses. |
Key implications
The MercuNorth study establishes a robust pre-Minamata Convention baseline for blood mercury in pregnant Arctic women, revealing the highest risk in Indigenous communities consuming traditional marine foods. Its standardized approach enables reliable future trend assessment and underscores the need for integrated biomonitoring and dietary data in heavy metal certification programs.
Citation
Adlard B, Lemire M, Bonefeld-Jørgensen EC, Long M, Ólafsdóttir K, Odland JO, Rautio A, Myllynen P, Sandanger TM, Dudarev AA, Bergdahl IA, Wennberg M, Berner J, Ayotte P. MercuNorth – monitoring mercury in pregnant women from the Arctic as a baseline to assess the effectiveness of the Minamata Convention. International Journal of Circumpolar Health. 2021;80(1):1881345. doi:10.1080/22423982.2021.1881345
Mercury (Hg) is a neurotoxic heavy metal found in various consumer products and environmental sources, making it a major public health concern. Its regulation is critical to protect vulnerable populations from long-term health effects, such as neurological impairment and cardiovascular disease. The HMTC program ensures that products meet the highest standards for mercury safety.
