5.1 Activities Contributing to Exposure and Ingestion of Soil/Dust: Dr. Natalie Freeman

Dr. Freeman opened the discussion on how to identify soil-pica children by showing video footage from her observational studies on how children come into contact with soils and household dusts. The video showed children engaging in various behaviors that contribute to exposures, such as putting objects in their mouths, playing with pets, handling food, eating after playing outdoors, sucking thumbs, cleaning fingernails, playing in sandboxes, and engaging in other hand-to-mouth activities. Dr. Freeman explained that the extent of exposure depends on many factors, such as where children play, what they wear, and how often they wash their hands. She noted further that the number of times a day children wash their hands is often less than parents think, primarily because parents often do not oversee this behavior. Dr. Freeman added that exposures can occur even when children are relatively inactive. Specifically, she stated that mouthing behavior was often greatest during periods of "down time," such as just before children take naps or while they watch television.

Dr. Freeman acknowledged that this particular research project did not attempt to quantify the amounts of soil ingested by the various activities, but she indicated that exposures may be significant. Citing a research project from the 1980s as an example, she noted that as much as 10,000 mg of soil can adhere to certain types of candies, when dropped outdoors (reference not provided). In conclusion, she emphasized that the various activities that contribute to exposures to soil and dust are typical children's behavior, and do not involve direct consumption of soils. Though she has not quantified these exposures, Dr. Freeman suspected that the cumulative effect of the various behaviors can lead to substantial ingestion of soils in some children (e.g., those who play vigorously outdoors, and who frequently engage in mouthing behavior, and who rarely wash their hands).

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