Ancient Maya Peoples and Toxic Mercury Pollution:
The ancient Maya had a penchant for painting almost everything red. Archaeologists have found uncounted artifacts that the Maya reddened, including sculptures, monuments, walls, plazas, pottery and EVEN THEIR DEAD … in ceremonial funerals.

Maya people were so fascinated with painting things red, some went beyond the normal red-ochre (iron based hematite) pigments … that they also imported cinnabar (a mercury sulfide mineral HgS), as a decorative red vermillion pigment … along with liquid Hg mined in volcanic regions of Honduras and central México (Teotihuacan).

The very toxic liquid mercury (Hg) and cinnabar (HgS) were then distributed by the Maya peoples, through long-distance trade. … The precise geographic extents of documented Maya Hg contaminations are currently found at 17 different southern highlands and south-central lowlands locations ranging from Belize down to El Salvador,
… along with 3 occurrences in the northern Yucatán lowlands, in Yucatán’s Hg-rich lakes of Lago Cobá and Cenote Xcach, and the Chunchucmil Maya site in Yucatan. (See Figure below)

Yet, note that outside of some 2006 testing of floor plaster samples from Chunchucmil, tests that unexpectedly showed significant mercury contaminations, unfortunately, very few archeologists studying the Maya peoples think to test archeological objects or materials for toxic mercury.

Environmental Contamination by the Maya’s Use of Toxic Mercury:
The run-off from the paint enters cenotes, lakes & waterways, deposits in the sediments, where anaerobic bacteria then transform cinnabar into highly toxic methylmercury.

Over time, the toxic organo-mercury (methylmercury) moves into the local food chains (esp through fish) and accumulates in much higher levels in the food chain, through biomagnification.**

Up to this point in archeological-toxicological studies, not much is documented about the impacts of mercury pollution on the ancient Maya nor about broader ecosystem deletirious health effects.

“In the Lago Cobá core, total Hg concentrations began to increase above “background” values (∼0.02 μg g−1) approximately 40 CE, during the Late Preclassic period (Fig. 2), and continued to rise into the Classic period, reaching maxima ∼2.3 μg g−1 from approximately 250 to 300 CE.”

“(Mercury contamination) Concentrations then decreased steadily, returning to background values by approximately 520 CE, and remained <0.5 μg g−1 to the top of the core (2023 CE) (for Lake Coba).”

“Three periods of high Hg concentration were recorded in the Cenote Xcach sediment core. The first interval began around 125 CE and lasted until approximately 200 CE, with maximum concentrations around 3 μg g−1. The second episode of high Hg concentration occurred from 330 to 370 CE and reached a maximum value of ∼2.0 μg g−1, similar in both magnitude and timing to the Hg peak in the Lago Cobá core. The third episode of high Hg was the time of greatest metal concentrations, with largest values in the Cenote Xcach core measured in sediments deposited from approximately 535 to 820 CE, during which Hg averaged 8.4 ± 4.8 μg g−1 and registered a maximum value of ∼18 μg g−1 approximately 720 CE.”

…
When we note the times of toxic mercury contaminations of the 2 Yucatan lake/cenote sediments, it becomes clear that it was the local Maya people’s use of toxic mercury in paints that created the contaminations, that peaked at 18 ug/g Hg contamination.

**For toxicological contexts: Plants and soil microbes are documented to be harmed by mercury contamination levels above 0.35 ug/g. Remember (as noted above) the form of mercury contamination matters most. Methylmercury is the most poisonous and bioaccumulative organic form, meanwhile inorganic mercury in soil is generally poorly absorbed by plant roots, though soil dust or direct ingestion poses risks to children and pregnant women.

Ecological risk contamination factors classify soil mercury above 1 ug/g as moderate to high risk, so the current Yucatan mercury levels of up to 18 ug/g found today, likely represent significant risks to ancient local Yucatec Maya peoples.

https://www.science.org/doi/10.1126/sciadv.aeh3280

https://www.science.org/doi/10.1126/sciadv.aeh3280

https://onlinelibrary.wiley.com/doi/full/10.1002/gea.21868


Additional links to toxic mercury contaminations and the ancient Maya are available upon request.

Dr. Steven M. Fry


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