Tooth Chemistry Uncovers Origins of St. Helena’s Liberated Africans

Remains of Africans freed from illegal slave ships and buried on St. Helena are revealing fresh details about how enslaved people were sourced and moved before forced embarkation across the Atlantic, according to a new study published in Science. By linking chemical clues preserved in tooth enamel with ancient DNA and documentary records, researchers reconstructed likely childhood homelands and early-life mobility for 152 individuals.

After Britain abolished the slave trade in 1807, the Royal Navy intercepted illicit vessels and brought many “liberated Africans” to St. Helena. Nearly one-third died soon after arrival from malnutrition and disease, and their bodies were later uncovered during archaeological excavations in 2007–2008. Since then, community groups have sought ways to honor lives long obscured by history.

The research, led by Xueye Wang and colleagues, used strontium isotope ratios—specifically ^87Sr/^86Sr—measured in tooth enamel. Because enamel forms during childhood and resists later chemical change, it can retain a signature of the local geology where a person grew up. When compared with environmental baselines, those signatures can indicate whether individuals likely spent early years near particular regions.

The results point to origins spanning a broad landscape from coastal western Central Africa to farther inland areas. The pattern includes regions corresponding to parts of modern Angola, Zimbabwe, and surrounding southern African areas, highlighting that “one-size-fits-all” sourcing narratives do not capture the complexity of recruitment.

Crucially, the team found evidence that some enslaved people may have been forcibly relocated within the interior years before reaching Atlantic ports. While many individuals show enamel signatures consistent with regional continuity during childhood, others display chemical shifts suggesting movement—sometimes toward coastal trading centers.

One case suggests a child’s likely relocation occurred between about ages seven and nine, based on isotope transitions aligned with tooth development. Such findings offer rare, biologically grounded timelines for disruptions that would otherwise be invisible in records.

The study argues that combining isotopes with genetic data can more precisely identify likely homelands, which may inform contemporary debates around remembrance, reburial, and—when appropriate—repatriation. At the same time, the researchers caution that because origins may be geographically diverse, decisions cannot be based on simplified assumptions.

In a related Perspective, R. Alexander Bentley contextualizes the work’s implications for both science and public memory, emphasizing that evidence should support community-led approaches to honoring individuals rather than dictating outcomes.