A Toxic Price to Pay: Wealthy citizens in medieval Europe had poisoning from lead-glazed plates

Ancient Origins

Rich city dwellers in medieval northern Europe had elevated lead and mercury levels that probably caused them serious health problems. Fewer rural people, who were poorer, had elevated heavy metals and those that did had less of the toxins in their systems than city dwellers.
An analysis of medieval skeletons by a Danish research team shows poisonous lead had entered the bodies of people buried in cemeteries in northern Germany and Denmark. The study says the lead could have been introduced through several sources but rules out absorption after death.
The medieval people would not have known how poisonous lead is, of course, or they probably wouldn’t have used it to glaze their kitchenware and put it in coins. Other sources of the heavy metal in the villagers’ systems may have included the lead-lined roofs, where drinking water was collected, as well as stained-glass windows.
The researchers examined the remains of people from six cemeteries, both urban and rural, in the two countries and revealed high levels of lead and mercury for city dwellers. Fewer people who lived in the countryside had elevated levels, says a press release from Southern Denmark University.

"The exposure was higher and more dangerous in the urban communities, but lead was not completely unknown in the country. We saw that 30 percent of the rural individuals had been in contact with lead—although much less than the townspeople,” Professor Kaare Lund Rasmussen of University of Southern Denmark’s Department of Physics, Chemistry and Pharmacy, said in the press release.

"Lead poisoning can be the consequence when ingesting lead, which is a heavy metal. In the Middle Ages you could almost not avoid ingesting lead, if you were wealthy or living in an urban environment. But what is perhaps more severe, is the fact that exposure to lead leads to lower intelligence of children.”

A stained-glass window in Schleswig, German; remains in a cemetery there were analyzed for the study. Only the rich could afford such windows. (Photo by Frank Vincentz/Wikimedia Commons)

Some of the symptoms of lead poisoning in kids include learning difficulties, developmental delay, loss of appetite and weight, vomiting, hearing loss, fatigue and sluggishness, according to WebMd. Constipation and abdominal pain affect both children and adults. WebMD.com says children are primarily at risk of lead poisoning, but adults too suffer ill effects from it, including high blood pressure, joint and muscle pains, lower mental function and headache. Adults also suffer from pain or numbness of extremities, bad moods, abnormal or reduced sperm counts and premature birth or miscarriage.
The glazed pottery, used more in the more affluent towns than in the country, was a big source of lead, according to the press release from the University of Southern Denmark.

"In those days lead oxide was used to glaze pottery. It was practical to clean the plates and looked beautiful, so it was understandably in high demand. But when they kept salty and acidic foods in glazed pots, the surface of the glaze would dissolve and the lead would leak into the food," Rasmussen said.

Rasmussen and colleagues examined 207 skeletons from cemeteries in Rathaus Markt in Schleswig (Germany) and Ole Worms Gade in Horsens (Denmark). The remains from both were from medieval cemeteries in wealthier towns that had more contact with the world than people in the countryside.

An aerial shot of Skt. Alberts cemetery on the island of Ærø, Denmark (Aegislash; Museum/SDU)

They also studied bodies from cemeteries in St. Clements outside of Schleswig (Germany), Tirup outside of Horsens (Denmark), Nybøl in Jutland (Denmark) and St. Alberts Chapel on the island of Ærø (Denmark), the press release says,
The team tested the skeletons mercury content. That element, also poisonous to humans, was employed in making red pigment cinnabar and for gilding. Medicines were also prepared from mercury to treat syphilis and leprosy, the press release states.
Again, city dwellers had more mercury than rural folk. Amazingly, about half the people examined had leprosy, which was treated with mercury.
Featured image: The skull of a young girl who suffered from syphilis; she would have been a candidate for treatment with mercury in the Middle Ages. (Birgitte Svennevig/SDU)
By Mark Miller