More than 2,000 years ago, the Maya built a complex water filtration system out of materials collected miles away. Now, reports Michelle Starr for Science Alert, researchers conducting excavations at the ancient city of Tikal in northern Guatemala have discovered traces of this millennia-old engineering marvel.
As detailed in the journal Scientific Reports, the study’s authors found that the Maya built the Corriental reservoir filtration system as early as 2,185 years ago, not long after settlement of Tikal began around 300 B.C.
The system—which relied on crystalline quartz and zeolite, a compound of silicon and aluminum, to create what the researchers call a “molecular sieve” capable of removing harmful microbes, heavy metals and other pollutants—remained in use until the city’s abandonment around 1100. Today, the same minerals are used in modern water filtration systems.
“What’s interesting is this system would still be effective today and the Maya discovered it more than 2,000 years ago,” says lead author Kenneth Barnett Tankersley, an archaeologist at the University of Cincinnati, in a statement.
According to Science Alert, archaeologists previously thought that the first use of zeolite for water filtration dated to the early 20th century. Researchers have documented other types of water systems—including ones centered on sand, gravel, plants and cloth—used in Egypt, Greece and South Asia as early as the 15th century B.C.
“A lot of people look at Native Americans in the Western Hemisphere as not having the same engineering or technological muscle of places like Greece, Rome, India or China,” says Tankersley. “But when it comes to water management, the Maya were millennia ahead.”
Per the statement, water quality would have been a major concern for the ancient Maya, as Tikal and other cities across the empire were built on porous limestone that left little water available during seasonal droughts. Without a purification system, drinking from the Corriental reservoir would have made people sick due to the presence of cyanobacteria and similarly toxic substances.
Members of the research team previously found that other reservoirs in the area were polluted with mercury, possibly from pigment the Maya used on walls and in burials. As Kiona N. Smith reported for Ars Technica in June, drinking and cooking water for Tikal’s elite appear to have come from two sources that contained high levels of mercury: the Palace and Temple Reservoirs. Comparatively, the new research shows that Corriental was free of contamination.
The researchers write that the Maya probably found the quartz and zeolite about 18 miles northeast of the city, around the Bajo de Azúcar, where the materials naturally purified the water.
“It was probably through very clever empirical observation that the ancient Maya saw this particular material was associated with clean water and made some effort to carry it back,” says co-author Nicholas P. Dunning, a geographer at the University of Cincinnati, in the statement. “They