Arsenic-laced pigments have been detected in more than 100 older books and documents across libraries and secondhand bookstores in Japan.
Arsenic Pigments in Historical Books
Old books containing toxic arsenic-inclusive pigments have turned up in libraries and secondhand bookstores nationwide. The findings center mainly on publications from the Edo to Meiji periods, with researchers confirming over 100 items so far.
Minerals containing arsenic compounds, such as orpiment, served as yellow pigments in ancient times. Artisans manufactured them artificially during the Edo period to make them easier to acquire, using yellow and green dyes mixed into paints for the covers of Japanese books and the coloring of ukiyo-ye prints. Sales of these materials faced restrictions as poisonous substances by about the middle of the Meiji period.
Bright green pigments containing arsenic compounds also emerged in Europe and America during the 18th and 19th centuries, appearing on book covers and illustrations. Acute poisoning from ingesting arsenic brings on severe vomiting and impaired consciousness, sometimes leading to death. In 19th-century America, instances occurred where individuals fell gravely ill after putting arsenic used in books into their mouths.
Did You Know? Mineral-based arsenic compounds like orpiment were used historically as yellow and green pigments for book covers, maps, and ukiyo-ye prints before being regulated as poisons around the middle of the Meiji period.
Discovery by Researchers and Library Responses
Following the discovery of arsenic-containing library books at a Danish university library in 2018, Koei Baba, a bibliographic researcher and specially appointed associate professor at the International Research Center for Japanese Studies in Kyoto, began analyzing books at domestic libraries and secondhand bookstores using X-ray fluorescence starting in 2022 while working as a researcher at the National Museum of Nature and Science.
Baba has surveyed roughly 20 libraries and secondhand bookstores in total, detecting arsenic in over 100 materials including Edo-to-Meiji period Japanese-style books, maps, ukiyo-ye prints, and Western books.
At one public library, testing revealed that about 30 items, including Japanese-style books and old maps, contained arsenic. Staff placed those items inside sealable bags and stored them inside cardboard boxes marked with red labels reading “Arsenic-containing materials inside.”
“I was surprised to find out that our library also has materials containing arsenic,” a staff librarian said, noting that the situation affects the health of staff entering the book stacks and that the library will thoroughly share information on how to handle the materials.
Building a database of risky books
Using the survey results, Baba created a database listing the titles and publication years of arsenic-containing publications and started making it available to select library personnel and researchers in October. The goal is to let libraries holding identical books implement appropriate safety measures by knowing which volumes pose risks.
Baba also recommends that libraries not only revise storage methods for those books but also digitize them to allow viewing without physical contact. The analysis continues, and further discoveries are anticipated.
“I think books containing arsenic will continue to be found,” Baba said, adding a desire to make the database useful overseas in the future given the large number of Japanese rare books held in libraries abroad.
Storing arsenic books safely
When did researchers start analyzing books for arsenic in Japan?
Koei Baba began analyzing books at domestic libraries and secondhand bookstores in 2022 while working as a researcher at the National Museum of Nature and Science, following a 2018 discovery at a Danish university library.
How are libraries currently storing books found to contain arsenic?
One public library stores the affected Japanese-style books and old maps by placing them inside sealable bags and keeping them inside cardboard boxes marked with red labels that read “Arsenic-containing materials inside.”
What types of historical materials have tested positive for arsenic?
The survey has detected arsenic in more than 100 materials, including Japanese-style books, maps, ukiyo-ye prints, and Western books published primarily from the Edo to Meiji periods.
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