Water Safety at Guatemala’s Maya City of Ucanal Analyzed

MONTREAL, CANADA—According to a statement released by the University of Montreal, recent analysis of the water system at the Maya city of Ucanal in northern Guatemala determined that it was effective at controlling visible pollutants and bacteria, but was contaminated by mercury, which would have been undetectable. Sediments from three reservoirs in the city were tested for biological pollution and chemical contamination: Aguada 2, located in a wealthy area; Aguada 3, located in a modest neighborhood; and Piscina 2, which was connected to the city’s drainage system. Jean Tremblay and Christina Halperin of the University of Montreal found that Ucanal’s water system was free of blue-green algae, which has been detected in other Maya water systems. The Aguada 2 reservoir was on high ground, where the water was filtered by rock-filled inlet channels. The study also suggests that the basins were surrounded by shady vegetation to keep the water cool, thereby hampering the growth of cyanobacteria. Additionally, the sediments were found to lack the phosphorus associated with algae growth. Low levels of fecal matter were detected in Aguada 2 as well. Aguada 3, however, was found to have been polluted with broken ceramics and domestic waste. This basin may have been used for wastewater collection or as a reservoir for workshop use rather than for drinking water. Less contamination was detected in Piscina 2, perhaps because it was connected to a drainage canal that kept the water flowing. But sediments from all three reservoirs were found to be contaminated with mercury from the bright red pigment cinnabar. The color was applied to steles, buildings, objects, and the dead. “It wasn’t just the elites using it—everyone was exposed,” said Halperin. As the use of cinnabar expanded, the levels of mercury in the basins increased. “They had no way of knowing it was toxic,” Tremblay said. For more on Ucanal, go to "A Dynasty Born in Fire."