Researchers from the University of Cincinnati and the University of California (USA) found the toxic substance in the two main reservoirs of the ancient Mayan city of Tikal, which was founded around the third century BC in the Northern part of modern Guatemala.

As reported by EurekAlert, discovery may shed light on long-standing mystery: more than a thousand years ago, the inhabitants suddenly left Tikal. Scientists have found that the reservoir in the center of this city was so polluted with mercury and algae that the water is likely to become unfit for drinking.

it is believed that this city was abandoned by its inhabitants around the ninth century of our era. Previous studies have linked it with a series of droughts, which Tikal was left without water. In the new study, it is assumed that the transformation of the main water reservoirs of Tikal in places that can cause disease, could lead to the collapse of the city.

Geochemical analysis showed that the two tanks located near the city Palace and the temple, contained alarmingly high levels of mercury. According to scientists, this substance could get into the water because of the citizens. Maya is widely used mercury as a component of paint, with which they adorned their buildings, utensils and other items.

During the rains, the mercury could leach from the paint and get into pools, where it settled for years, and has accumulated in bottom sediments. In addition, analysis of sediments from the Central reservoirs have indicated the presence of toxic algae called cyanobacteria. The use of this water, particularly during droughts, could cause human disease, even if it was boiled.

“We found two types of blue-green algae that produce toxic chemicals, says the study’s lead author David Lentz, Professor of biological Sciences at the University of California. They are very resistant to boiling. It is their property did the water in the tank is toxic and unfit for drinking.”

However, the researchers admit that people do not use water from these ponds for drinking and cooking. She was supposed to look dirty and have an unpleasant odor. By the way, other bodies of water in this city was not contaminated by toxic substances.

So the researchers were not unequivocally state that the Central pollution of water bodies has forced the Maya to leave the city. They considered sufficiently reliable hypothesis about a series of droughts. Citizens could experience serious problems finding drinking water, which the Central tanks couldn’t provide.