News

Mercury unlocks the secrets of the ancient Mayans

Mercury may be the key to unlocking new information about the ancient Mayan and their relationship with the environment, according to research led by Australian Catholic University (ACU).

ACU geoarchaeology expert Associate Professor Duncan Cook has pulled together data collected by archaeologists over the past century and paired them with exciting new research by environmental scientists.

The research shows that Maya people across Mexico and Central America had a history of mercury use that began at least two millennia before the arrival of the Spanish Conquistadors – and that this mercury can still be detected many centuries later in the environment today

Ancient Maya sites across Guatemala, Belize, the Yucatan of Mexico, El Salvador, and Honduras report environmental mercury concentrations that equal or exceed modern benchmarks for toxicity.

The ancient Mayan used a form of mercury called cinnabar for decorative and ceremonial purposes.  Archaeological records shows cinnabar (HgS) and rare finds of liquid mercury in important burial and religious contexts.

Elemental mercury has been found in pots and vessels and in buried soils at some Maya sites, and in tunnels underneath the pyramids of Teotihuacan, but no-one yet knows where this mercury came from and how the Maya obtained it.

Sources of cinnabar can be many hundreds of kilometres away from where mercury has been detected, at the  end of ancient trade routes.

"Archaeology has shown us that Maya were using mercury materials, but we're not getting any closer to understanding where the Maya got mercury from or how they produced liquid mercury," Assoc. Prof. Cook said.

"The way forward is combining what we see in the archaeological record with scientific measurements of legacy mercury to get a much richer understanding of how, where and when the Maya were using mercury based on what is still in the environment today. We’re working with archaeologists and using what we find in the present to better understand the past.

"When it comes to the Maya, much of what we think we know is being rapidly rewritten in the 21st century."

Mercury has a fascinating history. It was known to the ancient Greeks as ‘quicksilver’. Alchemists believed it had mystical properties and tried to use it to transform base metals into gold. There is evidence that it was used in ancient India and China as an aphrodisiac and contraceptive. Up until the mid-20th century it was used as a cure for syphilis.

“We are really only at the beginning of understanding the relationship between mercury and the Maya in the pre-Columbian times,” Assoc. Prof. Cook said.

“New research that begins to identify how widespread mercury pollution was in the environment of the Maya, and also identifies how impact the Maya were by mercury is now urgently needed.

“Once we get a better understanding of the environmental prevalence of mercury pollution, and a better understanding of how the Maya may have been impacted, by looking at mercury preserved in human remains, we can begin to consider where mercury exposure played a role in larger social-cultural change and trends.”

Assoc. Prof. Cook is the lead author of a new article in Frontiers in Environmental Science that located and summarised all published data sets collected from (or near) ancient Maya settlements that include environmental mercury measurements.

The locations with elevated mercury are typically former Maya occupation areas used in the Late Classic Period, situated within large urban settlements abandoned by c. 10th century CE.

It is most likely that the mercury detected in buried contexts at Maya archaeological sites is associated with pre-Columbian mercury use, especially of cinnabar, but possible from liquid mercury use too.

Associate Professor Duncan Cook is part of Australian Catholic University’s School of Arts and Humanities. His research expertise includes environmental geochemistry, palaeoenvironmental reconstruction, geochronology and geoarchaeology.

The full journal article in Frontiers in Environmental Science is available online: Frontiers | Environmental legacy of pre-Columbian Maya mercury (frontiersin.org)

The paper was co-authored by Dr Timothy Beach and Dr Sheryl Luzzadder-Beach from The University of Texas at Austin, Dr Nicholas Dunning from the University of Cincinnati, and Dr Simon Turner from University College London.