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An analysis of human exposure to trace elements from deliberate soil ingestion and associated health risks

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Abstract

Fifty-seven samples of soils commonly ingested in South Africa, Swaziland, Democratic Republic of Congo (DRC), and Togo were analyzed for the concentrations of arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), lead (Pb), manganese (Mn), nickel (Ni), and zinc (Zn) and their bioaccessibility in the human gastrointestinal tract. Bioaccessibility values were used to calculate daily intake, and hazard quotient of each trace element, and chronic hazard index (CHI) of each sample. Carcinogenic risk associated with As and Ni exposure were also calculated. Mean pseudo-total concentrations of trace elements in all samples were 7.2, 83.3, 77.1, 15.4, 28.6, 24.9, 56.1, 2.8, and 26.5 mg/kg for As, Cr, Mn, Co, Ni, Cu, Zn, Cd, and Pb, respectively. Percent bioaccessibility of Pb (13–49%) and Zn (38–56%) were highest among trace elements studied. Average daily intake values were lower than their respective reference doses for ell elements except for Pb in selected samples. Samples from DRC presented the highest health risks associated with trace element exposure with most of the samples having CHI values between 0.5 and 1.0. Some samples had higher than unacceptable values of carcinogenic risk associated with As and Ni exposure. Results indicate low trace element exposure risk from ingesting most of the soil samples.

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Acknowledgements

This work is based on the research supported in part by the National Research Foundation of South Africa (Grant Number: 82534).

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Authors and Affiliations

  1. Department of Environmental Sciences, School of Environmental Sciences, College of Agriculture and Environmental Sciences, University of South Africa, Florida, 1710, Roodepoort, South Africa

    Veronica M Ngole-Jeme

  2. Directorate of Research and Innovation, University of Venda, Private Bag X5050, Thohoyandou, 0950, Limpopo Province, South Africa

    Georges-Ive E Ekosse

  3. Office of the Deputy Vice Chancellor, Teaching and Learning, University of Zululand, Private Bag X1001, KwaDlangezwa, 3886, KwaZulu-Natal, South Africa

    Sandile P Songca

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  1. Veronica M Ngole-Jeme
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  2. Georges-Ive E Ekosse
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Correspondence to Veronica M Ngole-Jeme.

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Ngole-Jeme, V., Ekosse, GI. & Songca, S. An analysis of human exposure to trace elements from deliberate soil ingestion and associated health risks. J Expo Sci Environ Epidemiol 28, 55–63 (2018). https://doi.org/10.1038/jes.2016.67

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