Potential dietary, non-metabolic accumulation of arsenic (As) in seaweed-eating sheep's teeth: Implications for archaeological studies

Through analysis of total arsenic and other element concentrations in samples of enamel, cementum and dentine by hydride generation atomic fluorescence spectrometry (HG-AFS), as well as by bioimaging of radial tooth sections of sheep molars by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), this research demonstrates that in teeth of sheep exposed to dietary arsenic, arsenic predominantly accumulates in the infundibulum and occlusal dentine. The major route of uptake of arsenic in these teeth is therefore likely not by ingestion and metabolisation during growth of the tooth, as is thought to be the case for lead and barium, but rather due to direct surface contact, potentially even occurring during mastication. The implications of this type of in vivo chemical alteration of teeth for archaeological trace element studies are explored.