Temperature effect on perfluorooctane sulfonate toxicokinetics in rainbow trout (Oncorhynchus mykiss): Exploration via a physiologically based toxicokinetic model

Abstract

Salmonids are poikilotherms which means that their internal temperature varies with that of water. Water temperature thus controls many of their lifecycle processes and physiological functions, which could influence the mechanisms of absorption, distribution, metabolism and excretion (ADME) of many substances, including perfluorinated alkyl substances (PFAAs). However, the processes governing the fate of PFAAs are still poorly understood in fish. Here we developed a physiologically based toxicokinetic (PBTK) model for rainbow trout (Oncorhynchus mykiss) to study changes in physiological functions and PFAA ADME at different temperatures. The model was calibrated using experimental data from dietary exposure to perfluorooctane sulfonate at 7°C and 19°C. Predictions of PFOS concentrations were globally satisfactory at both temperatures, when accounting for the influence of temperature on growth, ventilation rate, cardiac output, clearances, and absorption rates. Accounting for the influence of temperature on tissue-plasma partition coefficients significantly improved predicted inorgan PFOS concentrations.

A Generalized Physiologically Based Kinetic Model for Fish for Environmental Risk Assessment of Pharmaceuticals

“…Predicted brain concentrations were less accurate than other organs since 40% of the predictions deviated from measurements by more than a 10-fold. Such discrepancies are also common in PBK studies by others (e.g., refs ( 30 ) and ( 70 )). For instance, 55% of the predicted brain concentrations deviated by more than a 10-fold for ionizable substances (bisphenol A and oxytetracycline) in Grech et al’s model.…”