Infection Control · single question
Where should amalgam waste be stored in the dental clinic to prevent mercury contamination?
Show answer and explanation
Correct answer: B. Sodium thiosulfate solution
B) Sodium thiosulfate (or appropriate amalgam waste container) — CORRECT.
Scrap amalgam must be stored in a SEALED, unbreakable container with a small amount of used radiographic fixer (which contains sodium thiosulfate) or under water/glycerin to prevent mercury vapor release. This retards evaporation of mercury from the amalgam scrap. Many offices use dedicated amalgam waste containers with these solutions. Proper disposal through an EPA-compliant amalgam separator and certified waste management is required.
A) Dry container: Insufficient — mercury vapor can evaporate from dry amalgam scrap, creating toxic exposure.
C) Regular waste: Amalgam is a hazardous waste — cannot be placed in regular clinical waste.
D) Sharps with formalin: Formalin does not prevent mercury evaporation; used for tissue fixation.
Scrap amalgam must be stored in a SEALED, unbreakable container with a small amount of used radiographic fixer (which contains sodium thiosulfate) or under water/glycerin to prevent mercury vapor release. This retards evaporation of mercury from the amalgam scrap. Many offices use dedicated amalgam waste containers with these solutions. Proper disposal through an EPA-compliant amalgam separator and certified waste management is required.
A) Dry container: Insufficient — mercury vapor can evaporate from dry amalgam scrap, creating toxic exposure.
C) Regular waste: Amalgam is a hazardous waste — cannot be placed in regular clinical waste.
D) Sharps with formalin: Formalin does not prevent mercury evaporation; used for tissue fixation.
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