Earliest Evidence of Man-Made Pollution Found in Tartar on 400,000-Year-Old Teeth

Human teeth from Qesem Cave. Israel Hershkovitz/Tel Aviv University
Janet Fang 20 Jun 2015, 13:44

An excavation of Qesem Cave near Tel Aviv yielded 400,000-year-old teeth containing the oldest direct evidence of an indoor barbeque – and the manmade environmental pollution that resulted. “On the one hand, we are dependent on technology, but on the other, we are inhaling its pollutants,” Ran Barkai of Tel Aviv University says in a news release. “Progress has a price.” 

Since the cave has been sealed off for the last 200,000 years, even the tartar (also called dental calculus) on the teeth was exceptionally preserved. Without modern dental practices and ultrasonic tools, the tartar accumulated on the teeth of these hominins (a group including us and our extinct ancestors) over their lifetimes. 

Researchers already knew that the Qesem Cave dwellers hunted, butchered, and roasted animals; they also extracted the bone marrow and used the bones as hammers to shape their stone tools. And now, after analyzing the chemical fingerprint of the biomolecules in the tartar, an international team led by Karen Hardy of Universitat Autònoma de Barcelona discovered that these early Paleolithic hominins enjoyed a balanced diet that also included plants and starches. Based on minute traces of essential fatty acids, it is likely that they ate nuts and seeds too. 

“Our research suggests that Lower Palaeolithic hominins were aware that a range of dietary sources must be consumed in sufficient quantity to ensure optimum survival,” Hardy says in a statement. There were also small plant fibers in the calculus, which might have been remnants of raw materials – or, more inventively, they might have been used to clean teeth.

In addition to food and prehistoric tooth picks, the team also found direct evidence of respiratory irritants entrapped in the tartar. These included traces of charcoal that likely resulted from inhaling smoke from the indoor fires that they used for roasting meat on a daily basis. This inhaled environmental pollution may have had a harmful effect on the health of our early ancestors.

“This is the first evidence that the world's first indoor BBQs had health-related consequences,” Barkai explains. “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.”

The findings were published in Quaternary International this week. 


Burned animal bones from Qesem Cave. Ruth Blasco

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