Fluorosis a problem in ancient Palmyra and Herculaneum

A history resource article by Mary Harrsch © 2015

The great archway leading to the grand collonade in Roman Palmyra.  Image
courtesy of Wikimedia Commons.

Note: This is a crosspost from my blog "History's Medical Mysteries".

A 2006 study by researchers at Kyushu University suggests residents of ancient Palmyra may have suffered from fluorosis, a chronic condition caused by excessive intake of fluorine compounds, marked by mottling of the teeth and, if severe, calcification of the ligaments.

Palmyra, today, is a World Heritage Site, a designation bestowed by the United Nation Educational, Scientific and Cultural Organization (UNESCO) in 1998. About 140 miles southeast of Damascus, the trading town once known as Tadmor (also spelled Tadmur) to the ancients, had been a center of trading since around 2000 B.C.E. But the town really bustled during the Roman Empire, and was filled with magnificent buildings throughout the 1st and 2nd century, beginning with the reign of Roman emperor Hadrian in 129 A.D. Hadrian renamed the oasis town "Palmyra Hadriana." But, the city's wealth faded with the decline of Roman influence in ancient Syria.

Starting in 1990, Japanese archaeologists began excavating the southeast necropolis of Palmyra and examined remains from the Roman era dating to the 2nd and 3rd centuries CE. Despite Palmyra's prosperity, "skeletal remains uncovered from the underground tombs of Palmyra have been found to retain an arthropathy of the joints, especially in the knee joint, bone fracture, marked bone lipping, spur formation, and eburnation (smoothed bone cavities)," reports the team led by Kiyohide Saito of the Archaeological Institute of Kashihara in the Journal of Archaeological Science. "A brown discoloration was also observed in the teeth."

Funerary Portrait of Yarkhai, Son of Ogga and Balya his Daughter
from Palmyra in Roman Syria 150-200 CE Limestone.  Photographed at the
Portland (Oregon) Art Museum by Mary Harrsch © 2012.

Fluoride in small concentrations is thought to deter microbes that cause tooth decay, the reason why about 66% of public water supplies in the United States are now fluoridated, according to the federal Centers for Disease Control and Prevention. But the Palmyrans' skeletal pathology, along with their discolored teeth, point to "fluorosis," a skeletal and enamel-damaging syndrome caused by ingesting too much fluoride over a long time, the researchers note. Looking at two large tombs for example, 25 of 33 individuals (76%) had discolored teeth in one, and 45 out of 65 (69%) had discolored teeth in the other.

Palmyrans drank, and still drink, water from wells tapped from ground water by long tunnels called "qanats" (an excellent Scrabble word). The area's geology and water table has been stable for about 7000 years, meaning water conditions now aren't greatly different from those during Roman times. In a bid to estimate the fluoride burden suffered by the town's ancient inhabitants, the researchers analyzed the water from these wells. Fluoride levels were as high as three parts per million in the water, a level that a National Academy of Sciences report in March warned could lead to fluorosis.

Archaeologists also ground up seven discolored teeth from tomb inhabitants, and compared them to seven others without discoloration, to reveal their fluoride concentration. In a chemical reaction, fluoride tends to replace some calcium in tooth enamel, making overexposure to fluoride particularly worrisome for children with growing teeth and bones. The ground-up teeth revealed that in the most discolored ones, about 22% of the calcium had been replaced by fluoride. "Thus, it was possible to directly verify that the ancient inhabitants of Palmyra did suffer from fluorosis," they conclude.

Vesuvius still hovers threateningly over the remains
of Herculaneum near Naples, Italy.
Photo by Mary Harrsch © 2007.

But, ancient Romans in Palmyra were not the only ancients to suffer from fluorosis. In 1981, when skeletal remains of victims of the Vesuvius eruption were found in the boat chambers on the shore of Herculaneum, researchers were provided with another opportunity to study dental conditions of Roman residents in a different ancient setting. In The Lancet, researchers Gino Fornaciari, M. Rognini and M. Torino reported finding only 3.8% of teeth recovered from 41 adults and 12 children damaged from tooth decay.

"This percentage is very low for both modern and ancient populations, in which values were between 8.5%, as in classic Magna Graecia and 11.4%, as in Roman Britain," the researchers stated.

However, the researchers also discovered a high percentage of individuals with calcium-deficient tooth enamel - a condition often resulting from starvation at an early age but also found in well-nourished individuals suffering from fluorosis.

"To elucidate this hypothesis, we examined thin sections of permanent teeth enamel (first molar) from 8 individuals found in the Herculaneum arches site and from a present-day patient from Pisa without evidence of fluorosis, as control," the researchers explained, "Enamel was analysed by energy dispersion system (EDS) with an SEM (Jeol) 6400 connected to a microanalysis system (EDS) (Noran-Tracor) with a detection of Z-MAX 30. Enamel fluorine concentrations were greater than 10-fold higher than normal (1500-3600 parts per million [ppm]) were recorded in 6 individuals."

Skeletal remains of 32 victims awaiting evacuation in the boat chambers of
Herculaneum.  Image courtesy of Tom Huesing via Flickr.

However, the condition was not found uniformly throughout all individuals in the sample and no fluorine was found in soil samples. But, researchers did find a strong concentration of fluorine in the water-bearing stratum of Herculaneum (3-8 mg/mL), with a calculated intake of 11.4-19.0 mg a day per person at the time of the volcanic eruption.

Researchers concluded that some of the sampled remains may have been visitors to the area, since the Roman aristocracy maintained vacation villas in the area.

References:

Torino, M., Rognini, M., & Fornaciari, G. (1995). Dental fluorosis in ancient Herculaneum. The Lancet, 345(8960), 1306. doi:10.1016/s0140-6736(95)90952-4

Yoshimura, K., Nakahashi, T., & Saito, K. (2006). Why did the ancient inhabitants of Palmyra suffer fluorosis? Journal of Archaeological Science, 33(10), 1411-1418. doi:https://doi.org/10.1016/j.jas.2006.01.016