title: Microplastic as a Vector for Chemicals in the Aquatic Environment: Critical Review and Model-Supported Reinterpretation of Empirical Studies.
abstract: The hypothesis that 'microplastic will transfer hazardous hydrophobic organic chemicals (HOC) to marine animals' has been central to the perceived hazard and risk of plastic in the marine environment. The hypothesis is often cited and has gained momentum, turning it into paradigm status. We provide a critical evaluation of the scientific literature regarding this hypothesis. Using new calculations based on published studies, we explain the sometimes contrasting views and unify them in one interpretive framework. One explanation for the contrasting views among studies is that they test different hypotheses. When reframed in the context of the above hypothesis, the available data become consistent. We show that HOC microplastic-water partitioning can be assumed to be at equilibrium for most microplastic residing in the oceans. We calculate the fraction of total HOC sorbed by plastics to be small compared to that sorbed by other media in the ocean. We further demonstrate consistency among (a) measured HOC transfer from microplastic to organisms in the laboratory, (b) measured HOC desorption rates for polymers in artificial gut fluids (c) simulations by plastic-inclusive bioaccumulation models and (d) HOC desorption rates for polymers inferred from first principles. We conclude that overall the flux of HOCs bioaccumulated from natural prey overwhelms the flux from ingested microplastic for most habitats, which implies that microplastic ingestion is not likely to increase the exposure to and thus risks of HOCs in the marine environment.
authors.affiliation: Aquatic Ecology and Water Quality Management Group, Department of Environmental Sciences, Wageningen University , P.O. Box 47, 6700 AA Wageningen, The Netherlands.|IMARES - Institute for Marine Resources & Ecosystem Studies, Wageningen UR , P.O. Box 68, 1970 AB IJmuiden, The Netherlands.
authors.forename: Albert A
authors.initials: AA
authors.lastname: Koelmans
authors.affiliation: School of Earth & Environmental Sciences, University of Portsmouth , Portsmouth, U.K.
authors.forename: Adil
authors.initials: A
authors.lastname: Bakir
authors.affiliation: School of Natural Resources and Environment, University of Michigan , Ann Arbor, Michigan 48109, United States.
authors.forename: G Allen
authors.initials: GA
authors.lastname: Burton
authors.affiliation: Laboratory of Environmental Toxicology and Aquatic Ecology, Ghent University , Ghent, Belgium.
authors.forename: Colin R
authors.initials: CR
authors.lastname: Janssen
mesh_terms: D000818:Animals; D059001:Aquatic Organisms; D017753:Ecosystem; D054750:Ecotoxicology / Q000379:methods; D008962:Models, Theoretical; D009792:Oceans and Seas; D009930:Organic Chemicals / Q000032:analysis / Q000737:chemistry / Q000493:pharmacokinetics; D010969:Plastics / Q000032:analysis* / Q000737:chemistry; D018570:Risk Assessment / Q000379:methods; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry
chemical_list: D009930:Organic Chemicals; D010969:Plastics; D014874:Water Pollutants, Chemical