Impressive Water Purifcation System Found at Ancient Maya City
More than 2,000 years ago in the ancient city of Tikal in northern Guatemala, Maya people apparently utilized a mineral called zeolite to purify their drinking water. The discovery, published in the journal Scientific Reports by anthropologists from the University of Cincinnati, represents the oldest known example of water purification in the Western Hemisphere.
Enduring for more than a millennium, Tikal was an impressive metropolis. For much of its history, extending from roughly 400 BC to 900 AD, it had thousands of structures and was home to tens of thousands of inhabitants. Key to maintaining that population was clean drinking water, but that wasn't always easy to come by.
"Given the area is subject to extreme seasonal droughts, a large population, and long-term occupation, the drinking water of Tikal was prone to contamination from a plethora of microbial sources and leachates from toxic minerals such as cinnabar," the researchers wrote.
To remedy that contamination, the Maya at Tikal apparently outfitted one of their largest reservoirs (pictured top), called Corriental, which was capable of holding 58,000,000 liters of water, with a complex filtration system.
"The filtration system was likely held behind dry-laid stone walls with the zeolites and macro-crystalline sand-sized quartz crystals further constrained with woven petate (woven reed or palm fiber matting) or other perishable porous material positioned just upstream of, or within the reservoir ingresses," the authors described.
The mineral zeolite was integral to the system.
"Zeolite is a non-toxic, three-dimensionally porous, crystalline, hydrated aluminosilicate," the researchers wrote. "Zeolite has adsorbent properties because its three dimensional microcrystalline pore spaces create a natural molecular sieve. Consequently, zeolite has the ability to filter out harmful microbes, nitrogenous compounds, and other dispersed insoluble and soluble inorganic and organic toxins from drinking water."
The anthropologists estimate that the water purification system could have been functioning as many as 2,185 years ago and may have been in operation for over a thousand years. Zeolite was likely collected from a source roughly thirty kilometers northeast of the city to regularly replenish the reservoir.
The Maya's utilization of zeolite is doubly impressive when you consider that the next known use of the mineral for water purification did not occur until the early twentieth century.
Source: Tankersley, K.B., Dunning, N.P., Carr, C. et al. Zeolite water purification at Tikal, an ancient Maya city in Guatemala. Sci Rep 10, 18021 (2020). https://doi.org/10.1038/s41598-020-75023-7