title: Variability of bioaccessibility results using seventeen different methods on a standard reference material, NIST 2710.
abstract: Bioaccessibility is a measurement of a substance's solubility in the human gastro-intestinal system, and is often used in the risk assessment of soils. The present study was designed to determine the variability among laboratories using different methods to measure the bioaccessibility of 24 inorganic contaminants in one standardized soil sample, the standard reference material NIST 2710. Fourteen laboratories used a total of 17 bioaccessibility extraction methods. The variability between methods was assessed by calculating the reproducibility relative standard deviations (RSDs), where reproducibility is the sum of within-laboratory and between-laboratory variability. Whereas within-laboratory repeatability was usually better than (<) 15% for most elements, reproducibility RSDs were much higher, indicating more variability, although for many elements they were comparable to typical uncertainties (e.g., 30% in commercial laboratories). For five trace elements of interest, reproducibility RSDs were: arsenic (As), 22-44%; cadmium (Cd), 11-41%; Cu, 15-30%; lead (Pb), 45-83%; and Zn, 18-56%. Only one method variable, pH, was found to correlate significantly with bioaccessibility for aluminum (Al), Cd, copper (Cu), manganese (Mn), Pb and zinc (Zn) but other method variables could not be examined systematically because of the study design. When bioaccessibility results were directly compared with bioavailability results for As (swine and mouse) and Pb (swine), four methods returned results within uncertainty ranges for both elements: two that were defined as simpler (gastric phase only, limited chemicals) and two were more complex (gastric + intestinal phases, with a mixture of chemicals).
authors: Environmental Sciences Group, Royal Military College of Canada, Kingston, Ontario, Canada.
authors: Iris
authors: I
authors: Koch
authors: Kenneth J
authors: KJ
authors: Reimer
authors: Martine I
authors: MI
authors: Bakker
authors: Nicholas T
authors: NT
authors: Basta
authors: Mark R
authors: MR
authors: Cave
authors: Sébastien
authors: S
authors: Denys
authors: Matt
authors: M
authors: Dodd
authors: Beverly A
authors: BA
authors: Hale
authors: Rob
authors: R
authors: Irwin
authors: Yvette W
authors: YW
authors: Lowney
authors: Margo M
authors: MM
authors: Moore
authors: Viviane
authors: V
authors: Paquin
authors: Pat E
authors: PE
authors: Rasmussen
authors: Theresa
authors: T
authors: Repaso-Subang
authors: Gladys L
authors: GL
authors: Stephenson
authors: Steven D
authors: SD
authors: Siciliano
authors: Joanna
authors: J
authors: Wragg
authors: Gerald J
authors: GJ
authors: Zagury
mesh_terms: D004784:Environmental Monitoring / Q000379:methods* / Q000592:standards*; D041981:Gastrointestinal Tract / Q000378:metabolism; D006801:Humans; D007753:Laboratories / Q000592:standards; D008954:Models, Biological; D012015:Reference Standards; D015203:Reproducibility of Results; D012989:Soil Pollutants / Q000032:analysis / Q000493:pharmacokinetics; D014481:United States; D037041:United States Government Agencies
chemical_list: D012989:Soil Pollutants