Divine Aleru is an accomplished biochemist and researcher with a specialized background in environmental toxicology, focusing on the impacts of heavy metals on human health. With deep-rooted expertise in microbiome signatures analysis, Divine seamlessly blends rigorous scientific training with her passion for deciphering the intricate relationships between environmental exposures and the human microbiome. Her career is distinguished by a commitment to advancing integrative health interventions, leveraging cutting-edge microbiome research to illuminate how toxic metals shape biological systems. Driven by curiosity and innovation, Divine is dedicated to translating complex environmental findings into actionable insights that improve individual and public health outcomes. 
Divine Aleru is an accomplished biochemist and researcher with a specialized background in environmental toxicology, focusing on the impacts of heavy metals on human health. With deep-rooted expertise in microbiome signatures analysis, Divine seamlessly blends rigorous scientific training with her passion for deciphering the intricate relationships between environmental exposures and the human microbiome. Her career is distinguished by a commitment to advancing integrative health interventions, leveraging cutting-edge microbiome research to illuminate how toxic metals shape biological systems. Driven by curiosity and innovation, Divine is dedicated to translating complex environmental findings into actionable insights that improve individual and public health outcomes. What was reviewed?
This review article comprehensively examines the pathways, metabolism, toxicity, health effects, and public health concerns associated specifically with inorganic and elemental mercury. The authors detail the chemical characteristics of these mercury forms and how these influence exposure routes, absorption, distribution, and organ-specific toxicity. The review focuses on both acute and chronic effects, highlights exposure sources such as cosmetics and dental amalgam, and discusses biomonitoring and management strategies. The article also considers potential links to neurodegenerative diseases and provides an international perspective with case studies from Korea and other countries.
Who was reviewed?
The review draws on a wide range of evidence, including experimental animal studies, occupational and population-based human studies, case reports, and epidemiological surveys. It incorporates data on children, adults, occupationally exposed workers, users of mercury-containing consumer products (like cosmetics and skin lightening creams), and the general public potentially exposed to mercury through environmental or household sources. Furthermore, the article references global regulatory and health agency reports, providing a broad context for understanding mercury exposure risks and health outcomes.
Most important findings
Elemental and inorganic mercury present distinct exposure risks due to their chemical forms and inherent bioavailability. Water-soluble inorganic mercury compounds are primarily absorbed via ingestion (7–15%) or dermal contact, accumulating mainly in the kidneys, where they can cause significant renal damage. Elemental mercury, commonly encountered as vapor from dental amalgams or industrial sources, is poorly absorbed via ingestion (<0.01%) but is rapidly absorbed through inhalation (up to 80%), distributing to all organs, with the brain and kidneys being key targets. Critically, elemental mercury is lipid soluble and can cross the blood-brain barrier, unlike inorganic mercury, and may enter the brain directly via the olfactory pathway.
Acute exposure to high concentrations of inorganic mercury can cause corrosive gastrointestinal and renal injury, while chronic exposure leads primarily to kidney damage and, in rare cases, hypersensitivity reactions such as acrodynia. Acute inhalation of elemental mercury vapor can result in severe respiratory and central nervous system toxicity, including tremors, cognitive disturbances (erethism), gingivitis, and nephrotoxicity. Chronic exposure, especially occupational, is associated with a triad of tremors, psychological symptoms, and gingivitis, and can affect immune function.
Key implications
For a heavy metal certification program such as HTMC, this review underscores the need for stringent regulation and monitoring of products containing inorganic or elemental mercury, particularly cosmetics and dental materials. The evidence supports the elimination or tight restriction of mercury in consumer products and industrial processes, as chronic, low-level exposures can produce significant kidney and neurological toxicity. The data validate urine mercury as the best biomarker for ongoing exposure, guiding testing strategies for certification and public health surveillance. Furthermore, the review highlights the importance of public education and product import controls, as well as the need for prompt exposure mitigation and use of chelation therapies in cases of poisoning. The ongoing debate and evidence around dental amalgam suggest that certification programs should at least require disclosure and encourage alternatives where feasible.
Citation
Park, D., & Zheng, W. (2012). Human Exposure and Health Effects of Inorganic and Elemental Mercury. Journal of Preventive Medicine and Public Health, 45(6), 344. https://doi.org/10.3961/jpmph.2012.45.6.344
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.
