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Soil ingestion rates for children under 3 years old in Taiwan
Citation:
Chien, L., M. Tsou, H. Hsi, P. Beamer, K. Bradham, Z. Hseu, S. Jien, C. Jiang, W. Dang, AND H. Özkaynak. Soil ingestion rates for children under 3 years old in Taiwan. Journal of Exposure Science and Environmental Epidemiology . Nature Publishing Group, London, Uk, , online, (2015).
Impact/Purpose:
The National Exposure Research Laboratory’s (NERL’s) Human Exposure and Atmospheric Sciences Division (HEASD) conducts research in support of EPA’s mission to protect human health and the environment. HEASD’s research program supports Goal 1 (Clean Air) and Goal 4 (Healthy People) of EPA’s strategic plan. More specifically, our division conducts research to characterize the movement of pollutants from the source to contact with humans. Our multidisciplinary research program produces Methods, Measurements, and Models to identify relationships between and characterize processes that link source emissions, environmental concentrations, human exposures, and target-tissue dose. The impact of these tools is improved regulatory programs and policies for EPA.
Description:
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. This is the first published soil ingestion study for children in Taiwan using tracer element methodology. In the current 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, even though 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 U.S. children. Titanium may not be a suitable tracer for estimating soil ingestion rates in Taiwan because the titanium dioxide is a common additive in food. 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 the current study are particularly important when assessing children’s exposure and potential health risk from nearby contaminated soils in Taiwan.
