University library finds books were toxic
OLD books contain many secrets. Myths. Legends. Plots. Scandals. But researchers in Denmark seeking invisible writings found something completely unexpected: poison.
University of Southern Denmark researchers have published an article in The Conversation detailing the deadly discovery.
The three rare books from the 16th and 17th century were undergoing X-ray fluorescence analysis. The idea was the radiation from the X-ray could discern different chemicals in their pages and bindings - and hopefully uncover lost texts.
Other books in the library had previously been found to have used recycled fragments of much older parchments - such as Roman and canonical law - in their bindings.
So the university was looking for more.
"We tried to identify the Latin texts used, or at least read some of their content," the researchers write. "But then we found that the Latin texts in the covers of the three volumes were hard to read because of an extensive layer of green pigment which obscures the old handwritten letters."
The books were taken to the lap for more intensive analysis intended to peer through the paint to find the chemicals of the print below.
But the analysis threw back an unexpected result.
The green stains were arsenic.
And it was as toxic as the day it was put there.
"This chemical element is among the most toxic substances in the world and exposure may lead to various symptoms of poisoning, the development of cancer and even death," the researchers write.
Their first thoughts went to the toxic tome in Umberto Eco's famous novel The Name of the Rose.
"Could something like this happen in reality? Poisoning by books?," they write.
It turns out, the pigment was not malicious.
Arsenic was a common component of the 'Paris green' paints and lacquers of the 19th century.
"In its heyday, all types of materials, even book covers and clothes, could be coated in Paris green for aesthetic reasons. Of course, continuous skin contact with the substance would lead to symptoms of exposure."
The paint was probably applied to the book covers to restore their looks, as well as protect them from vermin.
"Now, the library stores our three poisonous volumes in separate cardboard boxes with safety labels in a ventilated cabinet," the researchers write "We also plan on digitising them to minimise physical handling. One wouldn't expect a book to contain a poisonous substance. But it might."