PARENT SESSION
39 - Appraising and Quantifying Bioavailable Pollutant Fractions
7:50 AM to 6:30 PM, Tuesday, 14 May 2002
Exhibition Area

(39-06) PAH release in the gastrointestinal tract after ingestion of contaminated soil.

Van de Wiele, Tom^*,1, Verstraete, Willy¹, Siciliano, Steven¹, ¹ Ghent University, Gent, Belgium

ABSTRACT- Soil ingestion is one of the predominant exposure routes by which environmental contaminants enter the human body. Using a Simulator of the Human Intestinal Microbial Ecosystem (SHIME), the different steps of the gastro-intestinal tract were simulated to estimate oral bioavailability for polycyclic aromatic hydrocarbons (PAH) present in a soil matrix (50 + 1.1 g PAH/g DM) originating from a recreation area. PAH GC-MS analysis was performed on the pellet and supernatant of SHIME digests. PAH mass balances for the stomach digest was 94 %, duodenum 114 % and colon 96 %. Differences in PAH release from soil were seen along the digestion tract, with the highest amount, 1.2 %, occurring in the stomach digestion. Significant decreases in released PAH during the duodenal and colon digestion suggest that adsorption by proteins, bile salts or microbial biomass may be modulating PAH bioavailability at this later stage. No difference in bioavailability was observed for the 10 different PAH investigated. The estimated daily soil intake for children (0.4 g soil/day) and PICA children (5 g soil/day) results in a total PAH exposure of 0.24 and 3.0 g/day respectively. This is significantly more than the new European drinking water directive of 0.2 g total PAH exposure. Our data suggest that soil ingestion may be a major route of contaminant exposure in children.

Key words: bioavailability, PAH, soil, ingestion