title: Time-varying effects of aromatic oil constituents on the survival of aquatic species: Deviations between model estimates and observations.
abstract: There is a need to study the time course of toxic chemical effects on organisms because there might be a time lag between the onset of chemical exposure and the corresponding adverse effects. For aquatic organisms, crude oil and oil constituents originating from either natural seeps or human activities can be relevant case studies. In the present study the authors tested a generic toxicokinetic model to quantify the time-varying effects of various oil constituents on the survival of aquatic organisms. The model is based on key parameters applicable to an array of species and compounds with baseline toxicity reflected by a generic, internal toxicity threshold or critical body burden (CBB). They compared model estimates with experimental data on the effects of 8 aromatic oil constituents on the survival of aquatic species including crustaceans and fish. The average model uncertainty, expressed as the root mean square error, was 0.25 (minimum-maximum, 0.04-0.67) on a scale between 0 and 1. The estimated survival was generally lower than the measured survival right after the onset of oil constituent exposure. In contrast, the model underestimated the maximum mortality for crustaceans and fish observed in the laboratory. Thus, the model based on the CBB concept failed to adequately predict the lethal effects of the oil constituents on crustaceans and fish. Possible explanations for the deviations between model estimates and observations may include incorrect assumptions regarding a constant lethal body burden, the absence of biotransformation products, and the steady state of aromatic hydrocarbon concentrations in organisms. Clearly, a more complex model approach than the generic model used in the present study is needed to predict toxicity dynamics of narcotic chemicals. Environ Toxicol Chem 2017;36:128-136. © 2016 SETAC.
authors.affiliation: Institute for Water and Wetland Research, Department of Environmental Science, Radboud University, Nijmegen, The Netherlands.
authors.forename: Lisette
authors.initials: L
authors.lastname: De Hoop
authors.affiliation: Laboratory of Environmental Toxicology and Aquatic Ecology, Environmental Toxicology Unit (GhEnToxLab), Ghent University (UGent), Ghent, Belgium.
authors.forename: Karel P J
authors.initials: KP
authors.lastname: Viaene
authors.affiliation: Institute for Water and Wetland Research, Department of Environmental Science, Radboud University, Nijmegen, The Netherlands.
authors.forename: Aafke M
authors.initials: AM
authors.lastname: Schipper
authors.affiliation: Institute for Water and Wetland Research, Department of Environmental Science, Radboud University, Nijmegen, The Netherlands.
authors.forename: Mark A J
authors.initials: MA
authors.lastname: Huijbregts
authors.affiliation: Research Unit of Environmental and Evolutionary Biology, University of Namur, Namur, Belgium.
authors.forename: Frederik
authors.initials: F
authors.lastname: De Laender
authors.affiliation: Institute for Water and Wetland Research, Department of Environmental Science, Radboud University, Nijmegen, The Netherlands.
authors.forename: A Jan
authors.initials: AJ
authors.lastname: Hendriks
mesh_terms: D000818:Animals; D059001:Aquatic Organisms / Q000187:drug effects* / Q000378:metabolism; D001822:Body Burden; D005399:Fishes / Q000378:metabolism; D006801:Humans; D008962:Models, Theoretical; D010578:Petroleum / Q000378:metabolism / Q000633:toxicity*; D016019:Survival Analysis; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000378:metabolism / Q000633:toxicity*
chemical_list: D010578:Petroleum; D014874:Water Pollutants, Chemical
keywords: Hydrocarbon; Lethal body burden; Narcotic; Slope; Toxicokinetic-toxicodynamic model