Risky Mercury Contamination Found in Ancient Maya Cities

The Maya were heavy users of mercury and commodities containing mercury based on the discovery of mercury-filled containers and artifacts decorated with cinnabar at multiple sites

A recent study¹ reveals that mercury pollution is severely degrading the soil from former Maya cities. Modern urban environments and industrial landscapes are frequently contaminated with mercury. In light of the discovery of mercury-filled containers and cinnabar-painted artifacts at numerous Maya sites, the authors draw the conclusion that the Maya were heavy users of mercury and mercury-containing goods. In their day, this led to significant and dangerous pollution, which still exists today. In fact, there are areas where the contamination is so bad that it could still present a health risk to archaeologists today.

The authors conducted a comprehensive analysis of all available information on mercury levels in soil and sediments at ancient Maya sites. They demonstrate that mercury pollution is apparent everywhere at Classical Period sites for which data are available, with the exception of one site. Actuncan has a concentration of 0.016 ppm, while Tikal has an astounding 17.16 ppm. The Toxic Effect Threshold (TET) for mercury in sediments is set at 1 ppm for comparability.

The researchers come to the conclusion that the frequent use of mercury and goods containing mercury by the Maya of the Classic Period, between 250 and 1100 CE, is what causes this pollution, not its modern-day occurrence. Since the Maya used mercury for generations, the discovery of mercury buried deep in soils and sediments in ancient Maya settlements is difficult to explain but perhaps it was their art.

The authors draw attention to the discovery of sealed vessels containing liquid mercury at numerous Maya sites, including Quiriqua in Guatemala, El Paraso in Honduras, and the formerly multiethnic megapolis Teotihuacan in Central Mexico. Archaeologists have discovered artifacts painted with paints that included mercury in other parts of the Maya region, mostly paints manufactured from the mineral cinnabar. The authors draw the conclusion that cinnabar and mercury-containing paints and powders were widely utilized by the ancient Maya for ornamentation. The mercury may have then moved into the soil and water after leaching from ceramics, floors, walls, and patios.

They hypothesize that elemental mercury and cinnabar discovered at Maya sites may have been originally mined from known deposits on the northern and southern confines of the ancient Maya world and imported to the cities by traders because mercury is rare in the limestone that underlies much of the Maya region.

For the Maya, things might contain the soul-force known as ch'ulel, which was found in blood. Consequently, the vivid red cinnabar pigment was a priceless and precious item, but unbeknownst to them, it was also lethal, and its effects can still be seen in the soil and sediments surrounding historic Maya sites.

Chronic mercury poisoning damages the liver, kidneys, and central nervous system and results in tremors, blurred vision, hearing loss, paralysis, and mental health issues. The ancient Maya would have been at risk from all of this mercury. The fact that one of the final Maya kings of Tikal, Dark Sun, who reigned around 810 CE, is portrayed in frescoes as pathologically obese is perhaps relevant. Metabolic syndrome, which can be brought on by persistent mercury exposure, is known to have obesity as a side consequence.

If mercury exposure contributed to more significant sociocultural trends and changes in the Maya civilization, such as those at the end of the Classic Period, more investigation is required. The authors draw the conclusion that even the prehistoric Maya, who seldom ever utilized metals, significantly increased the environment's mercury contents. This finding indicates that there was also a "Maya anthropocene" or "Mayacene," as metal pollution appears to have been a result of human activity throughout history, as it did for the Romans who suffered from lead poisoning and the Victorians who had wallpaper laced with arsenic.

1. Cook, D. E., Beach, T. P., Luzzadder-Beach, S., Dunning, N. P., & Turner, S. D. (2022). Environmental legacy of pre-Columbian Maya mercury. Frontiers in Environmental Science, 10. https://doi.org/10.3389/fenvs.2022.986119