Echoes of contamination: Investigating heavy metal exposure at Wadi Faynan 100, Jordan

Abstract

Located in southern Jordan, Wadi Faynan was once a center for copper mining, smelting, and trade during the Early Bronze Age (EBA). The legacy of pollution in Wadi Faynan is visible in the contemporary landscape in the form of spoil tips and over 250 copper mines. The largest and possibly most significant EBA site in Wadi Faynan is Wadi Faynan 100 (WF100), which dates to EBA Ib (3300-3000 BCE) and has clear evidence of copper production including copper ores, slag, and copper casting molds. This research employed laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) to measure trace element concentrations of lead (Pb), cadmium (Cd), and arsenic (As) in human enamel from WF100 to determine if copper production during EBA Ib introduced heavy metal toxicity into the population. The sample consisted of 29 human teeth divided into three groups representative of different early life stages: first molars, premolars, and third molars. Although seven samples were excluded from the main analysis, the others all had trace amounts of Pb, Cd, and As. The samples were categorized into four different groupings for Pb based on their pattern of exposure across the growth layers of enamel: stable exposure, variable exposure, increasing exposure, and decreasing exposure. For Cd and As, each sample was identified as having concentrations above or below their limit of detections. Examination of the distribution of these heavy metals revealed inter- and intra-individual variation in exposure providing insight into participation in copper production activities and possible mobility patterns practiced at WF100.