Researchers working in Guatemala have found excessive ranges of mercury contamination on the historic Maya metropolis of Ucanal, 280km north-east of Guatemala Metropolis. Recognized in soil samples taken from throughout town’s core and its water reservoirs, the poisonous metallic might have prompted Ucanal’s inhabitants severe well being issues.
“The invention of mercury within the soil and reservoirs was anticipated, however the extent of it was a shock,” says Jean Tremblay, a PhD scholar in anthropology on the Université de Montréal in Canada and lead creator of the analysis paper revealed within the Journal of Archaeological Science: Stories. “What’s specific to our examine is that we systematically detected mercury all through town core (close to each elite and non-elite residential zones) and thru the whole occupation historical past of the positioning. Everybody was uncovered to mercury, no matter social standing.”
Tremblay and his colleagues recognized mercury in dried sediments from three of Ucanal’s historic reservoirs, which collected water that drained from the elements of town surrounding them. The typical mercury focus in every was at a degree labeled as closely polluted. Past the reservoirs, the workforce discovered the best focus of mercury in a ceremonial zone on the metropolis’s core, with decrease however nonetheless important quantities in samples taken from different areas, together with residential zones.
“Our examine exhibits that mercury dispersed into the atmosphere was mobilised throughout precipitation occasions and located its manner into the reservoirs as particles which gathered on the backside of the reservoirs,” Tremblay says.
Ucanal’s harmful ranges of mercury contamination in all probability outcomes from the Maya’s in depth use of cinnabar, a shiny crimson ore of mercury and sulphur. “Cinnabar was utilized in burial rituals, employed as pigments used to color buildings and as ornamental colouring for luxurious ceramics, engraved bone objects, carved stone ornaments and collectible figurines, and as ritual choices in themselves,” Tremblay explains.
“It’s believed that the Maya used this inorganic substance as a result of its intense crimson color related to blood and due to this fact to demise and rebirth, an essential a part of Maya cosmology,” he provides. “It differs from different crimson mineral pigments, reminiscent of these deriving from iron oxides, in its shiny purplish shades of crimson.”
The workforce discovered mercury contamination all through town’s historical past—a interval roughly from 800 BCE to 1521 CE—and seen that its ranges sharply elevated throughout the ninth century, when Ucanal reached its peak. This may occasionally have been as a result of Ucanal having elevated entry to long-distance commerce, Tremblay says, which might have introduced extra mercury to town.
With mercury such a distinguished characteristic of on a regular basis life, the individuals of Ucanal may have been uncovered to the poisonous metallic by ingesting water, unintentionally inhaling or ingesting it when grinding cinnabar, or when touching cinnabar throughout rituals. Nonetheless, it’s tough for researchers to know whether or not mercury present in skeletal stays outcomes from environmental publicity throughout life or occurred after demise due to the funerary rituals.
Over latest years, it has grow to be clear that mercury contamination was a widespread downside for the Maya. “Cinnabar was used all through the traditional Maya world and mercury has been measured in soils at quite a few historic Maya websites,” Tremblay says. One examine, revealed within the journal Frontiers in Environmental Science in 2022, lists 9 Maya archaeological websites the place elemental mercury and cinnabar have been discovered. Amongst them was the essential website of Copan in Honduras, the place mercury was recognized in ten contexts.
The workforce will proceed its archaeological work at Ucanal, Tremblay says. “This specific analysis highlights the chance that historic Maya peoples have been residing in environments that might pose adversarial well being results,” he says. “We intend to analyze additional the geochemistry of the positioning to additional doc the traditional native atmosphere.”
