Mercury in archaeological human bone: biogenic or diagenetic?. (August 2019)

• Record Type: Journal Article
• Authors: Emslie, Steven D.; Alderman, Audrey; McKenzie, Ashley; Brasso, Rebecka; Taylor, Alison R.; Molina Moreno, María; Cambra-Moo, Oscar; González Martín, Armando; Silva, Ana Maria; Valera, António; García Sanjuán, Leonardo; Vijande Vila, Eduardo
• Is Part Of: Journal of archaeological science. Volume 108(2019)
• Publication Date: 2019-08
• Subjects: Iberia -- Neolithic -- Chalcolithic -- Bronze age -- Cinnabar -- Pigments -- Toxicity -- Bone remodeling -- SEM EDS; Archaeology -- Periodicals; Archéologie -- Périodiques; 930.1
• DOI: 10.1016/j.jas.2019.05.005
• Languages: English
• ISSNs: 0305-4403

Abstract

Abstract: We investigated mercury (Hg) in human bone from archaeological sites in the Iberian Peninsula where the cultural use of cinnabar (HgS) as a pigment, offering or preservative in burial practices has been documented from the 4th to 2nd millennia cal B.C. (Late Neolithic, Copper Age and Bronze Age). Previous analyses have shown high levels of total mercury (THg) in human bone at numerous Neolithic and Chalcolithic sites in this region, but the question remains if this mercury entered the bones via diagenetic processes in the soil, especially where cinnabar powder and paint was found associated with the burials, or if it entered the bone via biogenic pathways from exposure to mercury from using cinnabar in life. We analyzed the humerus, femur, and tibia from a total of 30 individual burials from four Neolithic to Bronze Age sites in Iberia and found low to high values of THg in these bones, with the humerus showing significantly more THg concentrations than other skeletal elements when the THg was greater than 1 ppm. This pattern of Hg deposition in skeletal material from different sites and ages strongly suggests a biogenic origin for the mercury. In addition, absence of detectable Hg in bones with high to low values of THg using SEM EDS analysis further discounts diagenetic intrusion of Hg or cinnabar particles into the bone from the soil. It is likely that greater stress and bone remodeling rates from use of heavy tools and other activities in life are responsible for higher THg in the humerus than other skeletal elements, but additional research is needed to verify this. Highlights: Concentrations of mercury from 0.059 to 96.13 ppm were measured in archaeological human bone from Iberia. The source of the mercury is either biogenic from cultural use of cinnabar or from diagenetic processes in the soil. Mercury deposition is significantly higher in the humerus compared to measured values in the femur and/or tibia. Similar patterns of mercury deposition in bones from sites of different ages and locations imply a biogenic origin.