Dental Amalgam-Derived Mercury in Wastewater: A Systematic Review of Environmental and Health Impacts, and Control Strategies

Mahla   Mazloomian; Mohammad  Taghi Ghaneian; Niloufar Borhani  Yazdi; Mohammad Hassan  Ehrampoush; Farzan  Madadizadeh; Maryam  Gholami

doi:10.18502/jehsd.v10i4.20654

Mahla Mazloomian Environmental Sciences and Technology Research Center, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
Mohammad Taghi Ghaneian Environmental Sciences and Technology Research Center, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
Niloufar Borhani Yazdi Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
Mohammad Hassan Ehrampoush Environmental Sciences and Technology Research Center, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
Farzan Madadizadeh Medical Informatics Research Center, Institute for Futures Studies in Health, Kerman University of Medical Sciences, Kerman, Iran.
Maryam Gholami Genetics and Environmental Hazards Research Center, Abarkouh School of Medical Sciences, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.

DOI: https://doi.org/10.18502/jehsd.v10i4.20654

Keywords: Dental Amalgam, Mercury, Dental Unit Wastewater, Amalgam Separator, Environmental Pollution, Wastewater Management.

Abstract

Introduction: Dental amalgam, a mercury-based restorative material, is a significant point source of environmental mercury contamination in clinical wastewater. Mercury and other heavy metals from dental clinics enter wastewater systems untreated, posing risks to ecosystems and human health. This review uniquely bridges the critical gap between dental practice effluent pathways, quantitative environmental risk assessment, and practical evaluation of mitigation technologies.

Methods: A comprehensive literature search was conducted using Scopus, Web of Science, PubMed/MEDLINE, and Embase for publications from 2000 to 2024. This review focused on studies quantifying mercury in dental wastewater and evaluated the effectiveness of containment, treatment, and policy measures.

Results: The findings confirmed that dental clinics contribute substantially to mercury loads in wastewater, with a single chair releasing as much as 4.5 g/day. Reported mercury concentrations in dental effluent vary widely, ranging from 0.90 µg/L to 39 mg/L, reflecting differences in clinical practices and control measures. The primary mitigation technology is amalgam separators, which can remove more than 90% of amalgam particles and are increasingly required by regulations, such as the U.S. Environmental Protection Agency 2017. A multi-faceted approach combining separators, optimized chairside practices, waste segregation, and staff education is essential for effective management.

Conclusion: Despite the declining use of dental amalgam, it remains an important environmental concern. Effective mitigation requires a combination of stringent policies, proven technologies, and professional stewardship. Future efforts should prioritize standardized monitoring, long-term performance data on control measures, and robust cost-benefit analyses to guide sustainable dental practices.