A heavy pre-Hispanic head

This is the second report on a South-American male head. Hydrogen isotope ratios showed biological rhythms consistent with a South-American origin and Atomic Mass Spectrometry radiocarbon dating (AMS) is consistent with the last pre-Hispanic period (1418-1491 AD, 95.4% probability). Biopsies examined by light and electron microscopy revealed exceptionally well-preserved tissues. Elemental content of hair was determined by Inductively Coupled Plasma Mass Spectrometry (ICP/MS). High contents of toxins (lead, arsenic and mercury) detected were incompatible with life. The lack of evidence for lead in bones was also consistent with the proposal that the deposition of the toxins occurred post-mortem. We propose that the high content of metals in hair is the result of bacterial metabolic activity leading to metal complexation in extracellular polymeric substance (EPS) which protected bacteria from the environment. This mechanism may account for the tissues preservation and gives a hint at soil composition where the head was presumably buried.