Ancient Maya Cinnabar Use Contaminated Lakes With Mercury
Sediment cores from two Yucatan sites reveal repeated mercury spikes that reached multiple levels of the food chain.
Updated on Nov. 6, 2026 in Environmental
Researchers documented mercury contamination from cinnabar at the ancient Maya cities of Coba and Xcach on Mexico's Yucatan peninsula, with mercury spreading through the lake food chain. The findings were published in the journal Science Advances.
Why it matters
The study shows that ancient populations could alter their own environments through cinnabar use in pigments and ceremonies, with effects that reached aquatic life. It adds to earlier findings of mercury contamination at the Maya site of Tikal in Guatemala.
Sediment cores from lakes at Coba and Xcach recorded mercury spikes from about 125 AD to 200 AD and from about 535 AD to 820 AD at Xcach, with Coba's spike beginning around 250 AD and lasting about 150 years. Biological markers for bacteria, algae, cyanobacteria, shelled organisms and insect midges decreased or vanished in the lakes, though the extraction does not detail how the effects varied across species over time.
The players
Coba
An ancient Maya city on the Yucatan peninsula in Mexico, estimated to have had 60,000 to 90,000 people during the Classic Period.
Xcach
An ancient Maya site on the Yucatan peninsula in Mexico where sediment cores documented repeated mercury spikes.
Tikal
A major ancient Maya city in Guatemala that had earlier been studied for mercury contamination.
The details
Cinnabar, which is mostly mercury, was used by the Maya as a pigment in murals and temples and in ceremonies and funerary rites. Mercury leached from the cinnabar into surrounding soil and bodies of water, and researchers measured biological markers in lake sediments to assess effects on the food chain.
Timeline
Around 125 AD to 200 AD: first mercury spike at Xcach.
Around 250 AD: mercury spike at Coba begins, lasting about 150 years.
About 535 AD to 820 AD: third mercury spike at Xcach, lasting to the end of the Classic Period.
The Big Picture
The Coba and Xcach findings extend earlier evidence of mercury contamination at the Maya city of Tikal in Guatemala to additional sites on the Yucatan peninsula. Together, these studies suggest that cinnabar use was a recurring source of environmental mercury across the Maya lowlands rather than an isolated local practice.
The findings show how pigment and ritual materials can leave lasting traces in lake sediments and aquatic food webs, offering a model for tracing ancient human impacts on water quality. Researchers can apply the same sediment-core methods to other archaeological lakes to identify comparable contamination.
The takeaway
Ancient cinnabar use shows that mercury contamination from human activity can persist for centuries and move through the food chain. Future studies of archaeological lakes may reveal similar legacies elsewhere.
Further reading
For more on how past human activity has shaped waterways and ecosystems, explore our Environmental coverage.
