Soil ingestion rate determination in a rural population of Alberta, Canada practicing a wilderness lifestyle

• Published in: The Science of the total environment 2014-02, Vol.470-471, p.138-146
• Main Authors: Irvine, G., Doyle, J.R., White, P.A., Blais, J.M.
• Format: Article
• Language: English
• Subjects: Aboriginal; Alberta; Alberta oil sands; Diet - statistics & numerical data; Eating; Environmental Exposure - analysis; Environmental Exposure - statistics & numerical data; Feces - chemistry; Humans; In-situ bitumen extraction; Mass balance; Risk Assessment; Rural Population - statistics & numerical data; Soil; Soil ingestion; Soil Pollutants - analysis; Wilderness
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2013.09.037

The inadvertent ingestion of contaminated soil can be a major pathway for chemical exposure to humans. Few studies to date have quantified soil ingestion rates to develop exposure estimates for human health risk assessments (HHRA), and almost all of those were for children in suburban/urban environments. Here we employed a quantitative mass balance tracer approach on a rural population practicing outdoor activities to estimate inadvertent soil ingestion. This study followed 9 subjects over a 13day period in Cold Lake, Alberta, near the largest in situ thermal heavy oil (bitumen) extraction operation in the world. The mean soil ingestion rate in this study using Al Ce, La, and Si tracers was 32mgd−1, with a 90th percentile of 152mgd−1 and median soil ingestion rate of 18mgd−1. These soil ingestion values are greater than the standard recommended soil ingestion rates for HHRA from Health Canada, and are similar to soil ingestion estimates found in the only other study on a rural population. •Inadvertent soil ingestion was determined by elemental mass balance of soil tracers.•The mean soil ingestion rate was 52mgd−1 in people living outdoors.•This study followed 8 subjects for 13days and is the largest soil ingestion study of its kind.