The study decodes the “unexpected danger” that lurked beneath the ancient Mayan cities

Ancient Mayan cities were contaminated with “dangerous” levels of mercury that may have posed a health hazard to people living in the Mesoamerican civilization, according to new research.

The review of the studies, recently published in the journal Frontiers in Environmental Sciences, discovered the “unexpected danger” of mercury pollution beneath the soil surface of ancient Maya cities in Mesoamerica, likely caused by frequent use of mercury and mercury-containing products by people of this period between 250 and 1100 A.D

“Discovering mercury buried deep in soil and sediments in ancient Mayan cities is hard to explain, until we start looking at the archeology of the region that tells us the Mayans have used mercury for centuries,” said the Study co-author Duncan Cook of the Australian Catholic University said so.

In the study, scientists examined for the first time all data on mercury concentrations in soil and sediments at archaeological sites in the ancient Maya world.

They found mercury concentrations ranging from 0.016 parts per million (ppm) in some regions to “extraordinary” levels of 17.16 ppm in other places.

In comparison, the researchers say the Toxic Effect Threshold (TET) for mercury in sediments is defined as 1 ppm.

Citing previous studies, they say sealed vessels filled with liquid mercury have been reported at several ancient Mayan sites, including Quiriqua in Guatemala, El Paraíso in Honduras, and the multiethnic megalopolis Teotihucan in central Mexico.

Archaeologists have also previously unearthed mercury-containing paintings, mainly made from the mineral cinnabar, in other places in the Maya region.

Based on these observations, scientists say that the ancient Maya may have frequently used paints and powders containing cinnabar and mercury for decoration.

This mercury, they say, could seep out of patios, floor areas, walls and ceramics and spread into soil and water.

“For the Maya, objects could contain ch’ulelor soul force, which resided in the blood,” said Nicholas Dunning, another study co-author from the University of Cincinnati in the United States.

‘So, the bright red pigment of cinnabar was a priceless and sacred substance, but unbeknownst to them it was also deadly, and its legacy persists in the soils and sediments around ancient Mayan sites,’ explained Dr. Dunning.

Researchers suspect that the elemental mercury and cinnabar found at Maya sites may have originally been mined from known deposits on the northern and southern borders of the ancient Maya world and imported into cities by traders.

Widespread use of the metal may have posed a health hazard to the ancient Maya, scientists say.

Studies have demonstrated the toxic effects of chronic mercury poisoning, including damage to the central nervous system, kidneys, and liver.

The liquid metal is also known to cause tremors, impaired vision and hearing, paralysis and mental health problems.

Scientists call for more research to determine whether mercury exposure played a role in broader sociocultural change and trends in the ancient Mayan world.

“We conclude that even the ancient Maya, who barely used metals, caused a dramatic increase in mercury concentrations in their environment,” said Tim Beach, another study author from the University of Texas at Austin.

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