The excavations of the Ancient Maya world have continued to reveal surprises, and in 2020 two fascinating stories about urban water supply made headlines. Both were about the city of Tikal (known as Yax Mutal among the ancient Maya), but one was much sadder than the other. Tikal was an epicenter of power and was inhibited by Maya people from the sixth century BCE until the 10th century CE, and held between 60,000 and 90,000 people at its peak –this is quite a lot for the time period.
So the bad news first: scientists looked at the sediment around Tikal and found that two of the most important water reservoirs had toxic levels of mercury. They were able to trace the contamination to the red pigments that the Maya aristocracy adorned their central palace precincts with. Moreover, these archaeologists found toxic cyanobacteria in these reservoirs — and those life forms can’t easily be boiled away. In the second image, you can see an illustration from “Temple III”: an important structure. It shows “Dark Sun,” one of the last rulers of Tikal, as a fat man — he might have been struggling with mercury poisoning, as the toxin can affect a person’s metabolism and cause obesity.
But there was good news for these Maya. In a separate reservoir — a very large one called “Corriental,” the Maya had built a water tank (8th century BCE) with a highly sophisticated purification system. They used zeolites (mostly aluminum and silicon compounds), taken from a location 18 miles northeast of Tikal, which effectively filtered contaminants like mercury and cyanobacteria. The Corriental reservoir held 1.5 million gallons of water, and was also buttressed by a layer of woven plant material. The effort to make it took conscious planning and great effort.
The ecosystems of the Maya had the sort of environment which made water filtration crucial for large populations, since the region experienced regular cyclones, drought, and volcanic eruptions. The sophisticated use of zeolites to purify water was important for Tikal’s population to endure, and these ancient Maya were the first known peoples to employ this technique.
