The cities of the ancient Maya in Mesoamerica never fail to amaze. But beneath the surface of the soil lurks an unexpected danger: mercury pollution. In a review article in Borders in environmental sciencesthe researchers conclude that this pollution is not modern: it is due to the frequent use of mercury and mercury-containing products by the Maya of the classical period, between 250 and 1100 AD This pollution in places is so heavy that it still represents a potential danger to the health of unwary archaeologists.
Lead author, Dr Duncan Cook, Associate Professor of Geography at Australian Catholic University, said: “Mercury pollution in the environment is usually found in contemporary urban areas and industrial landscapes. Discovering Deep Buried Mercury in the soil and sediments in ancient Mayan cities it is difficult to explain, until we begin to consider the archeology of the region which tells us that the Mayans used mercury for centuries. ”
Ancient anthropogenic pollution
For the first time, Cook and colleagues looked at all data on mercury concentrations in soil and sediments at archaeological sites from the ancient Mayan world. They show that in the classical period sites for which measurements are available: Chunchumil in today’s Mexico, Marco Gonzales, Chan b’i and Actuncan in Belize, La Corona, Tikal, Petén Itzá, Piedras Negras and Cancuén in Guatemala, Palmarejo in Honduras and Cerén, a Mesoamerican “Pompeii”, in El Salvador – mercury pollution is detectable everywhere except in Chan b’i.
Concentrations range from 0.016 ppm of Actuncan to an extraordinary 17.16 ppm of Tikal. For comparison, the toxic effect threshold (TET) for mercury in sediments is defined as 1 ppm.
Large users of mercury
What caused this prehistoric mercury pollution? The authors point out that sealed vessels filled with “elemental” (ie liquid) mercury have been found in several Mayan sites, such as Quiriqua in Guatemala, El Paraíso in Honduras and the former multi-ethnic megacity Teotihucan in central Mexico. Elsewhere in the Maya region, archaeologists have found objects painted with mercury-containing paints, primarily based on the mineral cinnabar.
The authors conclude that the ancient Maya often used cinnabar and mercury-containing paints and powders for decoration. This mercury could then be leached from patios, floors, walls and ceramics and subsequently spread to soil and water.
“For the Maya, objects could contain ch’ulel, or force of the soul, residing in the blood. Hence, the bright red pigment of cinnabar was a precious and sacred substance, but unbeknownst to them it was also deadly and its legacy persists in the soil and sediments around ancient Mayan sites, “said co-author Dr. Nicholas Dunning, professor at the University of Cincinnati.
Since mercury is rare in the limestone that underlies much of the Mayan region, they speculate that the elemental mercury and cinnabar found at Mayan sites may have originally been mined from known deposits on the northern and southern borders of the ancient Mayan world and imported. in the city by the merchants.
Health Risks and ‘Mayacene’
All this mercury would have represented a danger to the health of the ancient Maya: for example, the effects of chronic mercury poisoning include damage to the central nervous system, kidneys and liver and cause tremors, impaired vision and hearing, paralysis and mental health problems. It is perhaps significant that one of Tikal’s last Mayan rulers, Dark Sun, who ruled around AD 810, is depicted in the frescoes as morbidly obese. Obesity is a known effect of metabolic syndrome, which can be caused by chronic mercury poisoning.
More research is needed to determine whether mercury exposure played a role in wider sociocultural change and trends in the Maya world, such as those towards the end of the Classical period.
Co-author Dr. Tim Beach, a professor at the University of Texas at Austin, said, “We conclude that even the ancient Maya, who barely used metals, caused a notable increase in the concentrations of mercury in their environment. This result. it is even more evidence that just as we live in the “Anthropocene” today, there was also a “Mayan Anthropocene” or “Mayacene”. Metal contamination appears to have been an effect of human activity throughout history. ”
Ancient Mayan Basins Contained Toxic Pollution: Study
Environmental legacy of pre-Columbian Mayan mercury, Borders in environmental sciences (2022). DOI: 10.3389 / fenvs.2022.986119
Citation: ancient Mayan cities were dangerously contaminated by mercury (2022, September 23) recovered on September 23, 2022 from https://phys.org/news/2022-09-ancient-maya-cities-dangerously-contaminated.html
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