Measuring and mitigating mercury vapour in the collection cabinets at Museums Victoria

Abstract

Mercury is present in the Museums Victoria collections in a variety of forms. These include mercuric chloride applied as a pesticide, pigments and paints containing mercury sulfide, scientific equipment containing liquid mercury and geoscience specimens including native mercury and cinnabar. All these materials can release mercury vapour into storage cabinets and have the potential to contaminate both storage surfaces and other nearby specimens. Extensive testing identified higher than acceptable levels of mercury vapour inside storage cabinets. Air from cabinets was sampled across all collecting disciplines including First Peoples, Society and Technology and Natural Sciences. Results showed levels of mercury vapour above 25 μg/m3 (TWA) in cabinets of bird skins and First Peoples’ artefacts treated with mercuric chloride pesticides and above 150 μg/m3 (TEEL) in the mineralogy collection. Mercury contamination was also detected on cabinet surfaces and storage boxes. Mitigation strategies implemented to reduce or handle this hazard include enclosing mercury minerals in gas barrier film, replacing contaminated cabinets with vented cabinets and engineering controls during the handling of specimens. Improved staff practices include procedures to dissipate vapour before accessing cabinets. Follow up testing confirmed a significant reduction of mercury vapour levels after the implementation of these mitigation strategies.