Evidence of soil-pica behaviour and quantification of soil ingested.

A previously published report on soil ingestion in children, revealed evidence that one of the subjects, a 3.5-year-old female, displayed soil-pica behaviour. Soil ingestion estimates for this child ranged from approximately 5 to 7 g d-1 for seven of eight soil tracers employed. The present paper revealed that the soil-pica behaviour occurred only in the second of the two weeks of observation, during which daily soil ingestion rates ranged from 10 to 13 g d-1. Tracer recovery studies displayed acceptable precision (i.e. 100% less than +/- 30%) for six of the eight tracers during the soil-pica episode (week 2). Evaluation of the weekly soil ingestion values of the remaining 63 subjects indicated no convincing evidence of soil-pica behaviour in this group of children aged 1-4.