Daily Soil Ingestion Estimates for Children at a Superfund Site

In: Risk analysis: an international journal, Volume 20, Issue 5, p. 627-636

Abstract

Ingestion of contaminated soil by children may result in significant exposure to toxic substances at contaminated sites. Estimates of such exposure are based on extrapolation of short‐term‐exposure estimates to longer time periods. This article provides daily estimates of soil ingestion on 64 children between the ages of 1 and 4 residing at a Superfund site; these values are employed to estimate the distribution of 7‐day average soil ingestion exposures (mean, 31 mg/day; median, 17 mg/day) at a contaminated site over different time periods. Best linear unbiased predictors of the 95th‐percentile of soil ingestion over 7 days, 30 days, 90 days, and 365 days are 133 mg/day, 112 mg/day, 108 mg/day and 106 mg/day, respectively. Variance components estimates (excluding titanium and outliers, based on Tukey's far‐out criteria) are given for soil ingestion between subjects (59 mg/day)2, between days on a subject (95 mg/day)2, and for uncertainty on a subject‐day (132 mg/day)2. These results expand knowledge of potential exposure to contaminants among young children from soil ingestion at contaminated sites. They also provide basic distributions that serve as a starting point for use in Monte Carlo risk assessments.