Lawluvi et al. 2026 — Maternal geophagy in Ghana and multi-metal exposure during pregnancy
This mini-review examines the practice of geophagy (intentional clay consumption) among pregnant women in Ghana and synthesizes available evidence on the heavy metal content of geophagic clays and the associated health risks for mothers and fetuses. Geophagic clays sampled in Ghana were found to contain Pb, As, Cd, Cr, and Hg at concentrations exceeding international food safety reference values, with bioaccessibility studies showing increased metal release under simulated gastric conditions, indicating that the orally ingested fraction available for absorption is higher than total-metal concentrations suggest. Naturally occurring radionuclides including K-40, U-238, and Th-232 were also detected in sampled clays, adding a radiological exposure dimension to the chemical metal burden. The review additionally documents microbial and parasitological contamination in geophagic clays, noting that the combined chemical, radiological, and biological hazards make geophagy a compound exposure pathway for pregnant women in Ghana, with fetal developmental risks from Pb, As, and Cd being the primary concern given their transplacental transfer properties.
Key numbers
- Metals detected in Ghanaian geophagic clays: Pb, As, Cd, Cr, Hg — all reported to exceed at least one international reference value
- Bioaccessibility increases under simulated gastric conditions (specific fold-change values in source tables)
- Radionuclides detected: K-40, U-238, Th-232
- Geophagy prevalence among pregnant women in sub-Saharan Africa reported as high; Ghana-specific estimates in source body
- Primary institution: Nuclear Regulatory Authority, Ghana
- Review scope: Ghanaian literature; cross-referenced with broader sub-Saharan Africa geophagy data
Methods (brief)
Mini-review; no primary sample collection. Synthesis of published analytical studies measuring heavy metals in geophagic clay samples from Ghana and comparable West African settings. Bioaccessibility data drawn from in vitro digestion studies applying PBET or similar gastric extraction protocols. Radionuclide data from gamma spectrometry studies. Review does not conduct its own meta-analysis; evidence is narrative synthesis.
Implications
Certification: Geophagy is not a food product but it is a significant oral exposure pathway for a vulnerable population (pregnant women and developing fetuses) in regions that supply agricultural commodities. The finding that geophagic clays exceed international reference limits for Pb, As, Cd, Cr, and Hg supports the broader argument that background metal body burden in certain source-region populations is elevated, which is relevant context for interpreting biomonitoring data from those regions.
Courses: Relevant to the dietary exposure module. Geophagy as a practice illustrates that heavy metal exposure pathways extend beyond conventional food matrices and that culturally specific practices must be considered in exposure assessments, particularly for maternal and infant populations.
App: No direct product concentration data. Informs exposure-route completeness documentation.
Microbiome: Combined microbial + chemical exposure via clay ingestion is a potential microbiome disruption pathway; relevant to metal-gut-axis if that page is developed.