Mercury (Hg) is a chemical of health concern worldwide that is now being acted upon through the Minamata Convention. Operationalizing the Convention and tracking its effectiveness requires empathy of the diversity and variation of mercury exposure and risk in populations worldwide. As part of the health plenary for the 15th International Conference on Mercury as a Global Pollutant (ICMGP), this review paper details how scientific understandings have evolved over time, from tragic poisoning events in the mid-twentieth century to important epidemiological studies in the late-twentieth century in the Seychelles and Faroe Islands, the Arctic and Amazon. Entering the twenty-first century, studies on diverse source-exposure scenarios (e.g., ASGM, amalgams, contaminated sites, cosmetics, electronic waste) from across global regions have expanded understandings and exemplified the need to consider socio-environmental variables and local contexts when conducting health studies. We conclude with perspectives on next steps for mercury health research in the post-Minamata Convention era.

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Electronic waste (e-waste) recycling releases mercury (Hg) into the environment, though to our knowledge Hg levels at such sites have yet to be examined on a worldwide basis. A systematic review of scientific studies was conducted to extract, analyze, and synthesize data on Hg levels in e-waste products, environments near recycling sites, and in people. Data were extracted from 78 studies from 20 countries, and these included Hg levels in 1103 electrical and electronic products, 2072 environmental samples (soil, air, plant, food, water, dust), and 2330 human biomarkers (blood, hair, urine). The average Hg level in products was 0.65 μg/g, with the highest levels found in lamps (578 μg/g). Average soil and sediment Hg levels (1.86 μg/g) at e-waste sites were at least eight times higher than at control sites. Average urinary Hg levels (0.93 μg/g creatinine) were approximately two-fold higher among e-waste workers versus control groups. Collectively, these findings demonstrate that e-waste recycling may lead to Hg contamination in environments and human populations in close proximity to processing sites. These findings contribute to a growing knowledge base of mercury exposure through diverse source–exposure pathways, and the work has potential policy implications in the context of the Minamata Convention.

Background: The Minamata Convention on Mercury (Article 4) prohibits the manufacture, import or export of skin-lightening products containing mercury concentrations above 1 ppm. However, there is a lack of knowledge surrounding the global prevalence of mercury-added skin-lightening products. Objective: The objective of this study was to increase our understanding of worldwide human mercury exposure and associated health risks from the use of skin-lightening products. Methods: A systematic search of peer-reviewed scientific literature was performed in four databases (PubMed, Web of Science Core Collection, Scopus, and Toxline). The initial search in July of 2018 identified 1,711 unique scientific articles, of which 34 were ultimately deemed eligible for inclusion after iterative screens at the title, abstract, and whole text levels. A second search was performed in November of 2020 using the same methods, of which another 7 scientific articles were included. All papers were organized according to four data groups 1) "Mercury in products", 2) "Usage of products", 3) "Human biomarkers of exposure"; and 4) "Health impacts", prior to data extraction and synthesis. Results: This review was based on data contained within 41 peer-reviewed scientific papers from 22 countries worldwide published between 2000 and 2020. In total, we captured mercury concentration values from 787 skin-lightening product samples (overall pooled central median mercury level was 0.49 µg/g, IQR: 0.02-5.9) and 1,042 human biomarker measurements from 863 individuals. We also synthesized usage information from 3,898 individuals, and self-reported health impacts associated with using mercury-added products from 832 individuals. Discussion: This review suggests that mercury widely exists as an active ingredient in many skin-lightening products worldwide, and that users are at risk of variable, and often high exposures. These synthesized findings help increase our understanding of the health risks associated with the use of these products.