Man-made pollution is an issue that plagues modern-day society, and apparently it affected ancient humans as well, as evidenced by newly discovered fossil teeth in Israel, a new study shows.

A team of researchers from Tel Aviv University, in collaboration with scholars from Spain, the United Kingdom and Australia, have uncovered proof of food and potential respiratory irritants entrapped in the dental calculus of 400,000-year-old teeth at Qesem Cave near Tel Aviv - the site of many major discoveries from the late Lower Paleolithic period.

In Qesem Cave, researchers reported the discovery of eight teeth, among the oldest hominin finds in southwest Asia, Forbes reported. They examined the dental tartar, and were able to determine the quality of air early Paleolithic people breathed inside Qesem Cave.

Using chemical and optical analysis, they identified several possible respiratory pollutants - including traces of charcoal and soot - in the teeth's dental plaque. These irritants appear to be the result of humanmade environmental pollution.

"Human teeth of this age have never been studied before for dental calculus, and we had very low expectations because of the age of the plaque," Professor Avi Gopher, of TAU's Department of Archaeology and Ancient Near Eastern Civilizations, said in a statement. "However, our international collaborators, using a combination of methods, found many materials entrapped within the calculus. Because the cave was sealed for 200,000 years, everything, including the teeth and its calculus, were preserved exceedingly well."

According to their results, air pollution may have resulted from smoke inhalation from indoor fires, which were used for roasting meat on a daily basis.

"This is the first evidence that the world's first indoor BBQs had health-related consequences," noted Professor Ran Barkai, one of the researchers. "The people who lived in Qesem not only enjoyed the benefits of fire - roasting their meat indoors - but they also had to find a way of controlling the fire - of living with it."

In addition to the presence of respiratory irritants, teeth analyses also revealed an early prehistoric "balanced" diet of plants, nuts and seeds, along with animal meat.

"This is one of the first, if not the first, cases of manmade pollution on the planet," Barkai concluded. "I live near power plants, near chemical factories. On the one hand, we are dependent on technology, but on the other, we are inhaling its pollutants. Progress has a price - and we find possibly the first evidence of this at Qesem Cave 400,000 years ago."

The findings were published in the journal Quaternary International.

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