title: Is there sufficient 'sink' in current bioaccessibility determinations of organic pollutants in soils?
abstract: Bioaccessibility tests can be used to improve contaminated land risk assessments. For organic pollutants a 'sink' is required within these tests to better mimic their desorption under the physiological conditions prevailing in the intestinal tract, where a steep diffusion gradient for the removal of organic pollutants from the soil matrix would exist. This is currently ignored in most PBET systems. By combining the CEPBET bioaccessibility test with an infinite sink, the removal of PAH from spiked solutions was monitored. Less than 10% of spiked PAH remained in the stomach media after 1 h, 10% by 4 h in the small intestine compartment and c.15% after 16 h in the colon. The addition of the infinite sink increased bioaccessibility estimates for field soils by a factor of 1.2-2.8, confirming its importance for robust PBET tests. TOC or BC were not the only factors controlling desorption of the PAH from the soils.
authors.affiliation: Soil Research Centre, University of Reading, Reading RG6 6DW, UK. c.d.collins@reading.ac.uk
authors.forename: C D
authors.initials: CD
authors.lastname: Collins
authors.forename: M
authors.initials: M
authors.lastname: Mosquera-Vazquez
authors.forename: J L
authors.initials: JL
authors.lastname: Gomez-Eyles
authors.forename: P
authors.initials: P
authors.lastname: Mayer
authors.forename: V
authors.initials: V
authors.lastname: Gouliarmou
authors.forename: F
authors.initials: F
authors.lastname: Blum
mesh_terms: D004784:Environmental Monitoring / Q000379:methods*; D007700:Kinetics; D009930:Organic Chemicals / Q000032:analysis*; D018570:Risk Assessment; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis*
chemical_list: D009930:Organic Chemicals; D012987:Soil; D012989:Soil Pollutants
keywords: Bioaccessibility; PAH; PBET; Risk assessment; Soil carbon