Use of LA-ICP-MS to evaluate mercury exposure or diagenesis in Inca and non-Inca mummies from northern Chile

We tested the hair of seven mummies housed at the Museo Regional de Iquique, northern Chile, to investigate evidence of mercury exposure in the Atacama Desert. Five mummies represent local inhumations and two came from a special burial known as capacocha, at Cerro Esmeralda, Iquique, northern Chile. The capacocha was a ritual of vital importance to both religious and political affairs wherein specially chosen children of both sexes were sacrificed throughout the Inca state. The cause of death of the two victims is unknown. Toxic cinnabar pigment has been found in the garments of the two Cerro Esmeralda sacrificed capacocha mummies. Using laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS), we evaluated if LA-ICP-MS was useful to discriminate between biogenic exposure and diagenesis of mercury. The capacochas inhumations’ hair presented a median level of 11.8 µg/g Hg vs.0.68 µg/g Hg found in non-capacocha mummies. We discuss these elevated levels of mercury in capacocha samples studied across and longitudinal sections of hair strands to elucidate possible endogenous consumption or perimortem contamination. We conclude that Cerro Esmeralda victims were subject to both external contamination and endogenous accumulation due to chronic Hg poisoning during the months-long capacocha ritual. Graphical abstract: [Figure not available: see fulltext.]