Temperature Effects on Toxicokinetics of Organic Chemicals in Aquatic Organisms

Global temperature changes have implications for the toxicokinetics (TK) of organic chemicals in aquatic organisms. Using the Arrhenius equation, we analyzed a comprehensive data set of toxicokinetic parameters that included a wide range of aquatic animal species and organic chemicals to quantify how temperature influences uptake and elimination rate constants. Our findings show that higher temperatures lead to increased rate constants for both uptake and elimination across all of the tested organisms and chemicals. As the Arrhenius slopes for uptake and elimination are similar, the bioconcentration factor is largely independent of the temperature. Adjusting for the organism's mass did not result in improved model fits. Furthermore, the octanol-water distribution coefficient (<i>D</i>_ow) was incorporated for a chemical-specific analysis. Compounds with higher <i>D</i>_ow values exhibited higher uptake rate constants and lower elimination rate constants compared to those with lower <i>D</i>_ow values. Despite these chemical-specific nuances, the overarching trend of a temperature-dependent rate constant increase remained evident. These insights contribute to a better mechanistic understanding of the effects of temperature changes on the TK of organic chemicals in aquatic ecosystems.