Mercury Hygiene — MFDS Part 1 MCQ
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Correct answer: A — Inhaled elemental mercury vapour can cause neurological and renal toxicity
Explanation lettering: C = shown as B · B = shown as C · E = shown as D · D = shown as E
A is correct. Dental personnel handling or removing amalgam may be exposed to elemental mercury vapour, principally by inhalation. About 80% of inhaled vapour is absorbed across the alveolar membrane. Mercury is then distributed to tissues, accumulates particularly in the kidneys and can cross the blood–brain barrier; chronic exposure may therefore cause neurotoxicity and nephrotoxicity. Elemental mercury is poorly absorbed after ingestion, making B incorrect. Mercury allergy can occur but is uncommon and is not inevitable or usually an immediate systemic reaction, excluding C. Dental amalgam is not radioactive, and corrosion of instruments is not the occupational-health basis for mercury hygiene, excluding D and E.
Reference: UK Health Security Agency. Elemental mercury and inorganic mercury: toxicological overview, sections on kinetics, dental occupational exposure and chronic inhalation effects. Updated 16 April 2025. https://www.gov.uk/government/publications/mercury-properties-incident-management-and-toxicology/elemental-mercury-and-inorganic-mercury-toxicological-overview