Detecting mercury in historic plant specimens

A University of Lincoln academic and PhD student have been working to develop innovative and economical methods to detect harmful mercury in preserved plant specimens in museums.

Vicky hard at work at the Louvre Research Labs

Vicky hard at work at the Louvre Research Labs

Historically, museums and other collectors applied pesticides to botanical materials to prevent insect and fungal damage, commonly using highly toxic compounds of mercury and arsenic. These poisons remain in the collections today, causing serious health and safety concerns in museums across the world.

Working with the National Museum of Wales (NMW), Professor Belinda Colston and Vicky Purewal’s research focuses on the chemistry of the natural ageing processes occurring in the mount paper used to display collections. They have demonstrated that as the mount paper degrades over 30 years or more, it will shine fluorescent under a UV-A lamp if mercury is present. The NMW has used the methodology to identify severely contaminated specimen sheets in its 800,000 strong collection and to prioritise which collections required immediate re-mounting.

Herbarium specimen

Herbarium specimen

 

Professor Colston says: “It is hoped that this method will allow safe, standard procedures to be

implemented within museums to protect personnel and visitors when handling the collections. It is a very simple and cheap technique that is accessible to even the smallest museums across the world.”