Arsenic is a common contaminant in potable waters in many regions of the world, and its bioaccumulation and associated health hazards are of a major concern. Our study focuses on human As exposure in ancient civilizations. Laboratory and field studies on Classic Maya ceramic vessel fragments and osteological remains of humans and animals collected from Tikal, Guatemala show high levels of As. The ubiquitous presence of As in several samples suggests how pervasive As distribution was during this time, and is indicative of long-term exposure for the Maya people and their animal contemporaries. We conducted laboratory simulations to determine the relationship between these elevated As levels in pottery and remains and to evaluate the potential pathways of As exposure and consumption. Leaching tests conducted on vessel fragments under different chemical conditions (hot and cold water, chocolate, soup, dilute acid) showed a rapid release of As from pottery sherds, indicating that use of this pottery can expose humans to As. Synchrotron based X-ray fluorescence and X-ray absorption (XANES) spectroscopy studies showed that As is present at high levels as AsO43- in the human and animal bones and teeth. Studies are in progress to evaluate the partitioning of AsO43- from aqueous solutions and into apatite to evaluate the levels of aqueous As necessary to see the levels of As detected in bone. The speciation of As in soils from Tikal is also being investigated to identify possible As sources in the vicinity. Together, these results will help explain the widespread elevated As levels observed in these ceramics and remains, as well as provide a mechanism through which to assess other historic mass arsenic poisonings.

Uncovering the sources of elevated arsenic levels in classic Maya human remains

253rd National Meeting (2017)

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