A startling new study reveals that the soil surrounding centuries-old skeletons contains information about how the deceased people spent their last days on Earth.
Bone analysts have studied the soil around skeletons dug up in two Danish towns. The analyses revealed that the soil contains mercury, which was present in the deceased people’s lungs, kidneys and livers at the time of death.
The amount of mercury in the soil can tell archaeologists whether the deceased were in medical treatment when they died. This is because the bacteria-killing mercury was used as medication as far back as the Roman times and all the way up to the start of the 20th century.
”These new findings enrich our history. Take for instance the skeleton of the child in Ribe in grave X1114 [see below]. Here we found mercury in the soil surrounding the skeleton, we can conclude that the child suffered from a serious disease, which was probably visible on the child’s skin,” says Associate Professor Kaare Lund Rasmussen, of the Department of Physics, Chemistry and Pharmacy at the University of Southern Denmark.
“Someone has wanted to help the child – most likely its parents – and they gave the mercury to the child. This gives us a few pieces for constructing a history for the person we have found.”
Rasmussen is the lead author of the new study, which is published in the journal Heritage Science.
Rasmussen and his colleagues took part in the recent archaeological excavations of
By analysing the child’s bones for mercury – which is a common method in archaeology – Rasmussen found that the child had been in mercury treatment a couple of years prior to its death.
And having conducted the new analysis of the soil surrounding the child’s body, he could see that the child was treated again in the days leading up to its death.
”I imagine that the child was ill, that the family tried to cure it with mercury, that it may have gone well for a while, but that the child suffered a serious relapse and was given a hefty dose of mercury which, however, did not save the child’s life.”
The technology used for extracting secrets out of the soil is known as ‘’Cold Vapour Atomic Absorption Spectroscopy’ (CV-AAS).
This method of analysis has been around for a few decades, but this is the first time that it is being used in connection with soil analysis from archaeological excavations.
“We’re using this technology in a new way. Of course, researchers have also previously made soil analyses in environmental chemistry. But the way we have used the technology in this latest study is brand new.”
The analysis can contribute with interesting information about the deceased people’s last day on Earth, because mercury doesn’t degrade in the same way as the rest of the substances in the human body.
After 800 years, the skeleton was found by archaeologists from Sydvestjyske Museer in Ribe and Horsens County Museum. Rasmussen took a soil sample, which he analysed using the CV-AAS instrument.
Rasmussen reckons the new discovery can change the way archaeologists will be digging for skeletons in the future:
Mercury was an important part of our ancestors’ everyday lives. The substance is highly poisonous, but also bactericidal, which is why it was used for centuries as medicine.
Kaare Lund Rasmussen’s research group has previously demonstrated that mercury was used in the treatment of leprosy and syphilis. Medieval monks also used mercury to make red ink (mercury sulphide is red).
By examining the mercury levels in skeletons and in the surrounding soil, it is possible to determine whether the deceased was:
”If you have taken part in an archaeological excavation, you know that archaeologists spend a lot of time on laying out bones, picking them up and putting them into boxes so they can be analysed. It must be kept in mind that we are not interested in death, but the life before death,” he says.
“The soil, on the other hand, is usually just scooped up into a wheelbarrow and thrown away. This has been done for more than 100 years, but now suddenly we can also make some inferences about the deceased person based on soil samples.
“Suddenly it’s no longer just the skeleton that’s interesting.”