Ingestion of soil and dust is a pathway of children’s exposure to several environmental contaminants, including lead, pesticides, and fecal contamination. Empirically based estimates of central tendency for soil consumption by children in high-income countries range from 9 to 135 dry mg/day. Using a Monte Carlo simulation, we modeled the mass of soil directly and indirectly ingested per day by rural Bangladeshi children and identified the parameters that influence the mass ingested. We combined data from observations of direct and indirect ingestion among children with measurements of soil mass on the children’s hands, mother’s hands, and objects to quantify soil ingestion/day. Estimated geometric mean soil ingestion was 162 dry mg/day for children 3–5 months, 224 dry mg/day for children 6–11 months, 234 dry mg/day for children 12–23 months, 168 dry mg/day for children 24–35 months, and 178 dry mg/day for children 36–47 months old. Across all age groups, children placing their hands in their mouths accounted for 46–78% of total ingestion and mouthing objects contributed 8–12%. Direct ingestion of soil accounted for nearly 40% of soil ingested among children 6–23 months old. Sensitivity analyses identified that the parameters most affecting the estimates were the load of soil on the child’s hand, the frequency of hand-to-mouth contacts while not eating, and, for children 6–23 months old, the frequency of direct soil ingestion. In a rural, low-income setting, children’s soil consumption was substantially more than the estimates for children in high-income countries. Further characterizing soil ingestion of children in low-income contexts would improve assessments of the risks they face from soil-associated contaminants.
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We gratefully acknowledge the WASH Benefits—Bangladesh study families who participated in the exposure assessment and provided environmental samples. This research was financially supported (in part) by grant OPPGD759 from the Bill & Melinda Gates Foundation to the University of California, Berkeley, and by a grant from the World Bank to the International Centre for Diarrhoeal Disease Research, Bangladesh. LHK was supported by the Stanford Wood’s Institute for the Environment Goldman Graduate Fellowship and the National Science Foundation Graduate Research Fellowship under Grant No. DGE-114747. Any opinion, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.
The authors declare that they have no conflict of interest.
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Kwong, L.H., Ercumen, A., Pickering, A.J. et al. Soil ingestion among young children in rural Bangladesh. J Expo Sci Environ Epidemiol 31, 82–93 (2021). https://doi.org/10.1038/s41370-019-0177-7
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