Soil ingestion rates for children under 3 years old in Taiwan

Abstract

Soil and dust ingestion rates by children are among the most critical exposure factors in determining risks to children from exposures to environmental contaminants in soil and dust. We believe this is the first published soil ingestion study for children in Taiwan using tracer element methodology. In this study, 66 children under 3 years of age were enrolled from Taiwan. Three days of fecal samples and a 24-h duplicate food sample were collected. The soil and household dust samples were also collected from children's homes. Soil ingestion rates were estimated based on silicon (Si) and titanium (Ti). The average soil ingestion rates were 9.6±19.2 mg/day based on Si as a tracer. The estimated soil ingestion rates based on Si did not have statistically significant differences by children's age and gender, although the average soil ingestion rates clearly increased as a function of children's age category. The estimated soil ingestion rates based on Si was significantly and positively correlated with the sum of indoor and outdoor hand-to-mouth frequency rates. The average soil ingestion rates based on Si were generally lower than the results from previous studies for the US children. Ti may not be a suitable tracer for estimating soil ingestion rates in Taiwan because the Ti dioxide is a common additive in food. To the best of our knowledge, this is the first study that investigated the correlations between soil ingestion rates and mouthing behaviors in Taiwan or other parts of Asia. It is also the first study that could compare available soil ingestion data from different countries and/or different cultures. The hand-to-mouth frequency and health habits are important to estimate the soil ingestion exposure for children. The results in this study are particularly important when assessing children's exposure and potential health risk from nearby contaminated soils in Taiwan.

Child soil ingestion in rural Ghana – frequency, caregiver perceptions, relationship with household floor material and associations with child diarrhoea

“…Based on a review of several studies with varying techniques, the EPA has recommended soil ingestion factors of approximately 20–40 mg/day for various age groups in children under 6 years in the United States, with a factor of 1000 mg/day recommended for children practicing soil‐pica and 50 000 mg/day recommended for children practicing geophagy . These factors are similar to soil ingestion factors that were measured in recent studies using biomarkers in Asia, including in Taiwan where average soil ingestion rates for children under 3 years old were estimated as 9.6 mg/day using Si as a tracer and 923 mg/day using Ti as a tracer and in China where average soil ingestion rates were 51.7 mg/day for children .…”

Soil ingestion among young children in rural Bangladesh

“…Children in our study ingested an estimated 162-234 dry mg soil/day, substantially higher than estimates reported by empirically based studies in the U.S. [7,[33][34][35][36], Canada [13], Germany [37], the Netherlands [17,38], and Taiwan [39]. Our model accounted for direct consumption of soil, which previous assessments using activity pattern models have not included [7,12,13].…”

Estimates of Soil Ingestion in a Population of Chinese Children

“…Nevertheless, children’s mouthing behaviors may differ between different countries or populations with different ethnic or lifestyle characteristics ( Tsou et al 2015 ), thereby influencing children’s SIRs between different countries or populations. As shown by Chien et al ( 2017 ), the SIR for children under 3 years of age in Taiwan based on the silicon (Si) tracer mass-balance technique showed SIRs to be lower than values found in the United States.…”