Condemned to metallum? The origin and role of 4th–6th century A.D. Phaeno mining campresidents using multiple chemical techniques

The Byzantine period (4th–7th centuries A.D.) site of Khirbet Faynan (Phaeno) was a state-run mining camp described in ancient sources as a destination for Christian martyrs and others prosecuted by the administration who were condemned to the mines (damnatio ad metallum). However, other evidence suggests that Phaeno had a much broader role and population in antiquity than that described by ancient writers. Here, strontium and oxygen isotope data on the level of migration into Phaeno were compared with elemental data on lead and copper skeletal levels to illuminate the varied exposure of local vs. non-local individuals to contaminated environments (presumably from working in mining and smelting operations). Dental enamel 87Sr/86Sr and δ18O data from 31 individuals excavated from the Southern Cemetery identified one individual born in a region with different strontium isotope values in the bedrock yet similar oxygen isotope signatures as Faynan. Most of the primarily locally-derived Faynan residents displayed skeletal copper and lead levels exceeding those seen in comparative samples, confirming that growing up and residing in the polluted environment of Faynan led to notable bioaccumulation of heavy metals and its resulting health effects. In addition, ten individuals had extremely elevated lead and copper levels in their skeleton resulting from more intensive exposure to contaminated environments, possibly through smelting and mining activities. These data confirm the relatively localized nature of this imperial operation and that this predominantly locally-derived population had different activities that put them ask varied risk for contamination by heavy metals.

Research highlights
► Only one individual in the Faynan sample spent their childhood in a different geological region as Faynan.
► Almost all residents of Faynan had higher-than-expected heavy metal levels in their skeletons.
► A few residents had extremely enhanced levels of heavy metals, suggesting they had more direct exposure to pollutants through mining or smelting.