This article first appeared in Issue 5 of our free digital magazine CURIOUS.
Watch out, old book enthusiasts – your collection might be poisoned. Starting with just one suspicious green tome that turned out to contain arsenic, the Winterthur Poison Book Project has so far identified a further 101 arsenic-tainted books out in the world, with more probably lurking undetected.
The culprit is a pigment called emerald green, aka copper acetoarsenite, used to color cloth book bindings. Discovered in 1808 and first manufactured as a pigment in 1814, the toxic compound has also been historically used as an insecticide.
Emerald green boomed in popularity in Britain and America in the 1850s. Indeed, many of the books in the database are from libraries across the US, with one found in a library in Leeds, England. The team even bought one in a local used bookshop for $15.
“These bindings are very common in libraries and private collections,” said Dr Melissa Tedone, Conservator and Lab Head for Library Materials Conservation at Winterthur Museum, Garden, & Library, in a statement.
Tedone’s interest was first piqued by Rustic Adornments for Homes and Taste, a green book published in 1857 with a “black, waxy excretion on the surface” and colorant that was “flaking off really easily,” she told National Geographic. Further analysis of the pigment by Dr Rosie Grayburn, using X-ray fluorescence and Raman spectroscopy, revealed that it did indeed contain arsenic.
Those most at risk from these books are people that work with them, such as librarians and researchers, so the project advises wearing nitrile gloves to handle books with emerald green pigment and wiping down any surfaces they are on with a disposable cloth, as they can shed tiny amounts of arsenic.
Arsenic poisoning is serious, and in some cases lethal. Short-term symptoms include nausea, diarrhea, and numb and tingling extremities. Long-term symptoms include skin lesions and an increased risk of various cancers.
So, anyone with a known interest in old books, if you find a dusty emerald green tome tucked away, approach with caution, and anyone gifted one, double check your bestower's intentions before accepting.