Heavy metals and trace elements contamination risks in peri-urban agricultural soils in Nairobi city catchment, Kenya Arcadius Martinien Agassin Ahogle 1,2 * , Sammy Letema 1 , Gertrud Schaab 3 , Veronica Ngure 4 , Abraham R. Mwesigye 5 and Nicholas K. Korir 6 1 Department of Spatial and Environmental Planning, Kenyatta University, Nairobi, Kenya, 2 Department of Soil Science, Faculty of Agronomic Sciences, University of Abomey-Calavi, Abomey-calavi, Benin, 3 Faculty of Information Management and Media, Karlsruhe University of Applied Sciences, Karlsruhe, Germany, 4 Department of Biological Sciences, Laikipia University, Nyahururu, Kenya, 5 School of Forestry, Environment and Geographical Sciences, College of Agriculture and Environmental Sciences, Makerere University-Kampala, Kampala, Uganda, 6 Department of Agricultural Science and Technology, Kenyatta University, Nairobi, Kenya Introduction: With urbanization and industrialization in the developing world, urban and peri-urban agriculture is increasingly contributing to urban food systems, employment, and income generation opportunities. However, urbanization and industrialization may release harmful pollutants, including heavy metals and trace elements into agricultural soils, posing ecological, environmental and public health concerns. This paper assessed the potential risks of soil contamination with heavy metals and trace elements in peri-urban farmlands in Nairobi city catchment in Kenya. Methods: A total of 60 soil samples were collected from ten vegetable farming zones (S1-S10) and processed following standard protocols. The concentrations of As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, V and Zn were analyzed in the samples using inductively coupled plasma-mass spectrometry (ICP-MS). Results and discussion: Results revealed that the soil samples have elevated concentrations of As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, V and Zn, with some elements including As (1.7%), Cd (13.3%), Mn (80%), Pb (1.7%) and Zn (11.7%) exceeding the permissible thresholds for agricultural soils. The spatial distribution of the elements exhibited three similar distribution patterns with slight variations between the hotspot sites of the different elements: (i) Co and Mn, (ii) Cu and Cr and (iii) As, Cd, Fe, Hg, Pb and Zn, while Ni and V exhibited singular spatial distributions compared to other elements. Elements such as As, Cd, Co, Fe, Hg, Mn, Pb and Zn appeared to be of anthropogenic enrichment, Frontiers in Soil Science frontiersin.org 01 OPEN ACCESS EDITED BY Christos Damalas, Democritus University of Thrace, Greece REVIEWED BY Chengyu Xie, Xiangtan University, China Hansong Chen, Zhejiang Normal University, China Fathy Elbehiry, Kafrelsheikh University, Egypt *CORRESPONDENCE Arcadius Martinien Agassin Ahogle ahoglearcadius@gmail.com SPECIALTY SECTION This article was submitted to Soil Pollution & Remediation, a section of the journal Frontiers in Soil Science RECEIVED 19 September 2022 ACCEPTED 12 December 2022 PUBLISHED 12 January 2023 CITATION Ahogle AMA, Letema S, Schaab G, Ngure V, Mwesigye AR and Korir NK (2023) Heavy metals and trace elements contamination risks in peri- urban agricultural soils in Nairobi city catchment, Kenya. Front. Soil Sci. 2:1048057. doi: 10.3389/fsoil.2022.1048057 COPYRIGHT © 2023 Ahogle, Letema, Schaab, Ngure, Mwesigye and Korir. This is an open- access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. TYPE Original Research PUBLISHED 12 January 2023 DOI 10.3389/fsoil.2022.1048057