Scientists believe the monks, who were buried in the cloister walk of the Cistercian Abbey at Øm, were either contaminated while preparing and administering medicines, or while writing the artistic letters of incunabula, or pre-1500 A.D. books. Kaare Lund Rasmussen, a University of Southern Denmark scientist at the Institute of Physics and Chemistry, suspects that ink used in the abbey's scriptorium was the culprit. "it is very human to lick the brush, if one wants to make a fine line. Even today "one should really not touch, or much less rub, the parchment pages of an incunabulum," he said adding that mercury "was used in the first place because cinnabar (a type of mercury) has this bright red, beautiful colour.” It is also known that metallic liquid mercury was given in vapor form to diseased patients. So if the monks "were just a little careless, they would be exposed this way, however, they might also be exposed during the preparation of the medicine."
Co-author Jesper Lier Boldsen discovered the previously undocumented disease FOS while examining the skeletons."We do not know if FOS was fatal, but it certainly looks painful and just as severe as leprosy," Lund Rasmussen said.
While working on the study, the researchers also noted that, due to different carbon signatures, some of the medieval individuals ate a mostly marine, fish-filled diet. Lund Rasmussen suggests that the others may have "preferred beer and meat, rather than fish and water." The Cistercians were, in principal, not allowed to eat meat from any four-footed animals, but the Franciscans do not appear to have always observed this practice. Although seafood may now contain high levels of mercury from environmental pollution, exposure from food would have been unlikely during the mediaeval period.
Lund Rasmussen and his team radiocarbon dated some of the studied bones, but they hope to do this for even more individuals from the test sample group, as this could reveal additional information about the possible link between mercury exposure and red ink use. By 1536, books were no longer written by hand, but were instead printed, so the scientists suspect the toxic red ink literally faded from the monastic picture.
The idea that the monks may have poisoned themselves while licking their brushes is quite plausible. One only has to look at the Radium Girls – women who painted dials of luminous watches. They would make a mixture of glue, water and radium powder into a glowing greenish-white paint, then apply it to the dials with a camel hair brush.. After a few strokes, the brushes would lose their shape, and the women couldn't paint accurately. They were isnstructed to point the brushes with their lips. Needless to say they suffered from radium poisoning leading in many cases to cancers of the upper and lower jaws.