Toxic heavy metals distribution in urban soils of Africa: a systematic review
Nontokozo Pertunia Mkhonza, Sandisiwe Zondo, Samukelisiwe Vilakazi
Environmental Monitoring and Assessment
Urban Farm DB summary
A systematic review synthesising 38 peer-reviewed studies (2010–2024) on heavy metals in African urban soils. Weighted mean concentrations of lead, cadmium and chromium exceeded FAO permissible limits in many countries, and industrial activity plus traffic emissions accounted for over half of the identified contamination sources. The review also documents strong geographic bias — Nigeria and Ghana are well studied while Egypt and Ethiopia are barely covered — and a shortage of measurements of bioavailable metal fractions, so the actual dietary risk from crops grown in these cities cannot be determined from this evidence base.