Polycyclic aromatic hydrocarbons are enriched but bioaccessibility reduced in brownfield soils adhered to human hands

The health risk associated with exposure to urban brownfields is often driven by the incidental ingestion of soil by humans. Recent evidence found that humans likely ingest the fraction of soil that passes a 45-μm sieve, which is the particle size adhered to the hands. We evaluated if PAH concentrations were enriched in this soil fraction compared to the bulk soil and if this enrichment lead to an increase in bioaccessability and thus an increase in incremental lifetime cancer risk for exposed persons. Soils ( n = 18) with PAH concentrations below the current Canadian soil quality guidelines for human health were collected from an Arctic urban site and were sieved to pass a 45-μm sieve. Soil PAH profiles were measured and bioaccessibility was assessed using the Simulator of the Human Intestinal Microbial Ecosystem (SHIME). PAHs were significantly enriched in the