title: Assessing the bioaccumulation potential of ionizable organic compounds: Current knowledge and research priorities.
abstract: The objective of the present study was to review the current knowledge regarding the bioaccumulation potential of ionizable organic compounds (IOCs), with a focus on the availability of empirical data for fish. Aspects of the bioaccumulation potential of IOCs in fish that can be characterized relatively well include the pH dependence of gill uptake and elimination, uptake in the gut, and sorption to phospholipids (membrane-water partitioning). Key challenges include the lack of empirical data for biotransformation and binding in plasma. Fish possess a diverse array of proteins that may transport IOCs across cell membranes. Except in a few cases, however, the significance of this transport for uptake and accumulation of environmental contaminants is unknown. Two case studies are presented. The first describes modeled effects of pH and biotransformation on the bioconcentration of organic acids and bases, while the second employs an updated model to investigate factors responsible for accumulation of perfluorinated alkyl acids. The perfluorinated alkyl acid case study is notable insofar as it illustrates the likely importance of membrane transporters in the kidney and highlights the potential value of read-across approaches. Recognizing the current need to perform bioaccumulation hazard assessments and ecological and exposure risk assessment for IOCs, the authors provide a tiered strategy that progresses (as needed) from conservative assumptions (models and associated data) to more sophisticated models requiring chemical-specific information. Environ Toxicol Chem 2017;36:882-897. © 2016 SETAC.
authors.affiliation: Department of Physical and Environmental Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada.
authors.forename: James M
authors.initials: JM
authors.lastname: Armitage
authors.affiliation: Office of Research and Development, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division, US Environmental Protection Agency, Duluth, Minnesota, USA.
authors.forename: Russell J
authors.initials: RJ
authors.lastname: Erickson
authors.affiliation: Department Bioanalytical Ecotoxicology, UFZ-Helmholtz Centre for Environmental Research, Leipzig, Germany.
authors.forename: Till
authors.initials: T
authors.lastname: Luckenbach
authors.affiliation: Department of Civil and Environmental Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
authors.forename: Carla A
authors.initials: CA
authors.lastname: Ng
authors.affiliation: School of Environmental Sciences, University of Guelph, Guelph, Ontario, Canada.
authors.forename: Ryan S
authors.initials: RS
authors.lastname: Prosser
authors.affiliation: Department of Physical and Environmental Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada.|ARC Arnot Research and Consulting, Toronto, Ontario, Canada.
authors.forename: Jon A
authors.initials: JA
authors.lastname: Arnot
authors.affiliation: Eawag, Department of Environmental Toxicology, Swiss Federal Institute of Aquatic Science and Technology, Duebendorf, Switzerland.|School of Architecture, Civil and Environmental Engineering, EPFL, Lausanne, Switzerland.|Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, Zurich, Switzerland.
authors.forename: Kristin
authors.initials: K
authors.lastname: Schirmer
authors.affiliation: Office of Research and Development, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division, US Environmental Protection Agency, Duluth, Minnesota, USA.
authors.forename: John W
authors.initials: JW
authors.lastname: Nichols
mesh_terms: D000818:Animals; D001711:Biotransformation; D005399:Fishes / Q000378:metabolism*; D005880:Gills / Q000187:drug effects / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008954:Models, Biological; D009930:Organic Chemicals / Q000737:chemistry / Q000378:metabolism*; D012106:Research; D018570:Risk Assessment; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000378:metabolism*
chemical_list: D009930:Organic Chemicals; D014874:Water Pollutants, Chemical
keywords: Bioaccumulation; Ecological risk assessment; Ionizable organic chemical (IOC); Toxicokinetics