Department of Environmental Chemistry, Swiss Federal Institute of Aquatic Science and Technology - Eawag, Dübendorf, Switzerland.
Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, Zürich, Switzerland.
Glob Chang Biol. 2023 Mar;29(5):1390-1406. doi: 10.1111/gcb.16542. Epub 2022 Dec 9.
The acceleration of global climate change draws increasing attention towards interactive effects of temperature and organic contaminants. Many studies reported a higher sensitivity of aquatic invertebrates towards contaminant exposure with increasing or fluctuating temperatures. The hypothesis of this study was that the higher sensitivity of invertebrates is associated with the changes of toxicokinetic processes that determine internal concentrations of contaminants and consequently toxic effects. Therefore, the influence of temperature on toxicokinetic processes and the underlying mechanisms were studied in two key amphipod species (Gammarus pulex and Hyalella azteca). Bioconcentration experiments were carried out at four different temperatures with a mixture of 12 exposure relevant polar organic contaminants. Tissue and medium samples were taken in regular intervals and analysed by online solid-phase extraction liquid chromatography high-resolution tandem mass spectrometry. Subsequently, toxicokinetic rates were modelled and analysed in dependence of the exposure temperature using the Arrhenius equation. An exponential relationship between toxicokinetic rates versus temperature was observed and could be well depicted by applying the Arrhenius equation. Due to a similar Arrhenius temperature of uptake and elimination rates, the bioconcentration factors of the contaminants were generally constant across the temperature range. Furthermore, the Arrhenius temperature of the toxicokinetic rates and respiration was mostly similar. However, in some cases (citalopram, cyprodinil), the bioconcentration factor appeared to be temperature dependent, which could potentially be explained by the influence of temperature on active uptake mechanisms or biotransformation. The observed temperature effects on toxicokinetics may be particularly relevant in non-equilibrated systems, such as exposure peaks in summer as exemplified by the exposure modelling of a field measured pesticide peak where the internal concentrations increased by up to fourfold along the temperature gradient. The results provide novel insights into the mechanisms of chemical uptake, biotransformation and elimination in different climate scenarios and can improve environmental risk assessment.
全球气候变化的加速引起了人们对温度和有机污染物相互作用的日益关注。许多研究报告称，随着温度的升高或波动，水生无脊椎动物对污染物暴露的敏感性更高。本研究的假设是，无脊椎动物的更高敏感性与决定污染物内部浓度和毒效的毒代动力学过程变化有关。因此，本研究在两种关键的广斧足类物种（食蚊鱼和霍氏溪蟹）中研究了温度对毒代动力学过程的影响及其潜在机制。在四个不同的温度下进行了生物浓缩实验，使用了 12 种具有代表性的极性有机污染物混合物。定期采集组织和介质样本，并通过在线固相萃取液相色谱高分辨串联质谱进行分析。随后，使用 Arrhenius 方程对毒代动力学速率与暴露温度的关系进行建模和分析。观察到毒代动力学速率与温度之间存在指数关系，可以通过应用 Arrhenius 方程很好地描述。由于吸收和消除速率的 Arrhenius 温度相似，因此在整个温度范围内污染物的生物浓缩因子通常保持不变。此外，毒代动力学速率和呼吸的 Arrhenius 温度也大多相似。然而，在某些情况下（西酞普兰、环丙嘧啶），生物浓缩因子似乎与温度有关，这可能是由于温度对主动吸收机制或生物转化的影响。在非平衡系统中，观察到的温度对毒代动力学的影响可能特别重要，例如夏季的暴露高峰，如通过现场测量的农药高峰的暴露模拟所示，内部浓度沿着温度梯度增加了四倍。这些结果为不同气候情景下化学物质吸收、生物转化和消除的机制提供了新的见解，并可以改善环境风险评估。
