Environmental Geochemistry and Health

, Volume 41, Issue 5, pp 1987–2009 | Cite as

The geochemistry of geophagic material consumed in Onangama Village, Northern Namibia: a potential health hazard for pregnant women in the area

  • Selma N. Kambunga
  • Carla Candeias
  • Israel Hasheela
  • Hassina MouriEmail author
Original Paper


Ingestion of geophagic materials might affect human health and induce diseases by different ways. The purpose of this study is to determine the geochemical composition of geophagic material consumed especially by pregnant women in Onangama Village, Northern Namibia and to assess its possible health effects. X-ray fluorescence and inductively coupled plasma mass spectrometry were used in order to determine the major, and trace elements as well as anions concentrations of the consumed material. The geochemical analysis revealed high concentrations of aluminium (Al), calcium (Ca), iron (Fe), magnesium (Mg), manganese (Mn), potassium (K), sodium (Na), and silica (Si); and trace elements including arsenic (As), chromium (Cr), mercury (Hg), nickel (Ni) and vanadium (V) as well as sulphate (SO42−), nitrate (NO3), and nitrite (NO2) anions comparing to the recommended daily allowance for pregnant women. The pH for some of the studied samples is alkaline, which might increase the gastrointestinal tract pH (pH < 2) and cause a decrease in the bioavailability of elements. The calculated health risk index (HRI > 1) revealed that Al and Mn might be a potential risk for human consumption. Based on the results obtained from the geochemical analysis, the consumption of the studied material might present a potential health risk to pregnant women including concomitant detrimental maternal and foetal effects.


Geophagy Geochemistry Termite mound soils Pregnant women 



The authors are grateful to the University of Johannesburg and the National Research Foundation (NRF, South Africa) Incentive Funding for Rated Researchers (Grant No. 91059) and Collaborative Postgraduate training programme (Grant No. 105295) for the financial support for this study. Carla Candeias is grateful to the Portuguese Institutions University of Aveiro, IU GeoBioTec (UID/GEO/04035/2013) and to FCT (SFRH/BPD/99636/2014) for the financial support of her work. Patrick Gevera and Olufunke Sanyaolu are thanked for their comments on the early draft of this manuscript. Anonymous reviewers and the Editor of the Journal are acknowledged for their valuable comments, which helped to improve the manuscript.


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Authors and Affiliations

  1. 1.Department of GeologyUniversity of JohannesburgJohannesburgSouth Africa
  2. 2.GeoBioTec, Geosciences DepartmentUniversity of AveiroAveiroPortugal
  3. 3.EpiUnit, Public Health InstituteUniversity of PortoPortoPortugal
  4. 4.Environmental and Engineering Geology DivisionGeological Survey of NamibiaWindhoekNamibia

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