Ancient Mayan cities are heavily contaminated with mercury

Some ancient Mayan cities have dangerously high mercury levels.

A review in frontiers in environmental science has shown that this mercury pollution originated with the ancient Mayans, who appear to have used much of the compound at certain points in their long history.

“Environmental mercury pollution is typically found in modern urban areas and industrial landscapes,” says lead author Dr. Duncan Cook, Associate Professor of Geography at the Australian Catholic University.

“The discovery of mercury buried deep in soil and sediment in ancient Maya cities is difficult to explain until we start looking at the archeology of the region, which tells us that the Maya used mercury for centuries.”

The international research team reviewed all available data on mercury exposure at ten different Mayan archaeological sites.

Seven of the ten sites had mercury contamination in at least one location. These sites mostly dated to the Late Classic, in the second half of the first millennium AD. All sites were abandoned by the 10thth Century.

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Mercury levels range from 0.016 parts per million (ppm) at Actuncan to 17.16 ppm at Tikal.

“Total mercury levels found today in some ancient contexts at Mayan sites are equal to or higher than the modern guidelines we have for safe soil mercury exposure limits, such as: B. WHO recommended safe limits for mercury in soil for agriculture. that’s 0.05 ppm,” says Cook.

“Our review indicates that numerous Mayan sites have total mercury levels that would be of concern if found in a playground or construction site.”

He adds, however, that it is “very difficult to say” how dangerous a particular Mayan site is.

“We just don’t know enough about the mercury found at ancient Mayan sites, how it got there, and what forms it takes in the environment today, 1,000 years or more after the Maya.”

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Researchers suggest several reasons for mercury exposure.

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Vessels containing pure liquid mercury have been found at several Maya sites. Elsewhere, the bright red mineral cinnabar, derived from mercury and sulfur, is a popular pigment.

“Cinnabar’s bright red pigment was a priceless and sacred substance, but unbeknownst to them, it was also deadly and its legacy lives on in soils and sediments surrounding ancient Maya sites,” says co-author Dr. Nicholas Dunning, Professor at the University of Cincinnati, USA.

It is not obvious what effect this mercury level had on the Maya civilization or on the health and behavior of the residents of these cities.

“What we need now is new multidisciplinary research on Mayan mercury to get closer to answering this question,” says Cook.

“There are already several excellent studies showing the presence of mercury in ancient human remains from the Maya world, but we need to link the sites of high mercury levels in buried soil and sediments to the Maya who lived there.

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“This means mercury analysis on human remains from the very same locations where geoscientists have discovered instances of elevated mercury that are still present today.”

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Naturally occurring mercury is rare in the limestone of the Maya region, suggesting it was imported.

“We conclude that even the ancient Maya, who hardly used any metals, caused the mercury concentrations in their environment to rise sharply,” says co-author Dr. Tim Beach, Professor at the University of Texas at Austin, USA.

cook tells cosmos He was one of the first researchers to identify mercury at a Maya site in the early 2000s — a surprising finding that has “haunted him ever since.”

“My colleagues and I are still fascinated by the story of how a pre-industrial society used mercury in the tropical forests of Central America 1,000 to 2,000 years ago in a way that preserves its chemical signature in the environment today,” he says.

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