title: Independent data validation of an in vitro method for the prediction of the relative bioavailability of arsenic in contaminated soils.
abstract: In vitro bioaccessibility (IVBA) assays estimate arsenic (As) relative bioavailability (RBA) in contaminated soils to improve accuracy in human exposure assessments. Previous studies correlating soil As IVBA with RBA have been limited by the use of few soil types and sources of As, and the predictive value of As IVBA has not been validated using an independent set of As-contaminated soils. In this study, a robust linear model was developed to predict As RBA in mice using IVBA, and the predictive capability of the model was independently validated using a unique set of As-contaminated soils. Forty As-contaminated soils varying in soil type and contaminant source were included in this study, with 31 soils used for initial model development and nine soils used for independent model validation. The initial model reliably predicted As RBA values in the independent data set, with a mean As RBA prediction error of 5.4%. Following validation, 40 soils were used for final model development, resulting in a linear model with the equation RBA = 0.65 × IVBA + 7.8 and an R(2) of 0.81. The in vivo-in vitro correlation and independent data validation presented provide critical verification necessary for regulatory acceptance in human health risk assessment.
authors.affiliation: †Office of Research and Development, United States Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States.
authors.forename: Karen D
authors.initials: KD
authors.lastname: Bradham
authors.affiliation: †Office of Research and Development, United States Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States.
authors.forename: Clay
authors.initials: C
authors.lastname: Nelson
authors.affiliation: ‡Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, SA 5095, Australia.
authors.forename: Albert L
authors.initials: AL
authors.lastname: Juhasz
authors.affiliation: ‡Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, SA 5095, Australia.
authors.forename: Euan
authors.initials: E
authors.lastname: Smith
authors.affiliation: §Office of Research and Development, United States Environmental Protection Agency, Cincinnati, Ohio 45224, United States.
authors.forename: Kirk
authors.initials: K
authors.lastname: Scheckel
authors.affiliation: ∥Department of Civil, Construction, and Environmental Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Obenour
authors.affiliation: §Office of Research and Development, United States Environmental Protection Agency, Cincinnati, Ohio 45224, United States.
authors.forename: Bradley W
authors.initials: BW
authors.lastname: Miller
authors.affiliation: †Office of Research and Development, United States Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States.
authors.forename: David J
authors.initials: DJ
authors.lastname: Thomas
mesh_terms: D000818:Animals; D001151:Arsenic / Q000493:pharmacokinetics*; D001682:Biological Availability; D004781:Environmental Exposure / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods*; D005260:Female; D051379:Mice; D008810:Mice, Inbred C57BL; D012989:Soil Pollutants / Q000493:pharmacokinetics*
chemical_list: D012989:Soil Pollutants; D001151:Arsenic