Background

Available literature and regulatory studies show that the severity of effects of beta-cyfluthrin (a synthetic pyrethroid) on fish is influenced by the magnitude and duration of exposure. To investigate how the exposure pattern to beta-cyfluthrin (constant vs peak) may influence the response of the fish, we used a mechanistic effect model to predict the survival and growth of the rainbow trout over its early life stages (i.e. egg, alevin and swim-up fry). We parameterized a toxicokinetic–toxicodynamic (TKTD) module in combination with a dynamic energy budget model enabling us to describe uptake and elimination, as well as to predict the threshold concentration for survival and sublethal effects (feeding behaviour and growth). This effect model was calibrated using data from an early life stage experiment where trout was exposed to a constant concentration of cyfluthrin. The model was validated by comparing model predictions to independent data from a pulsed-exposure study with early life stages of rainbow trout.

Results

The co-occurrence of effects on behaviour and growth raised the possibility that these were interrelated, i.e. impairment of feeding behaviour may have led to reduced food intake and slower growth. We, therefore, included ‘effect on feeding’ as mode of action in the TKTD module. At higher concentrations, the constant exposure led to death. The model was able to adequately capture this effect pattern in the calibration. The model was able to adequately predict the response of fish eggs, alevins and swim-up fry, from both the qualitative (response pattern) and quantitative points of view.

Conclusions

Since the model was successfully validated, it can be used to predict survival and growth of early life stages under various realistic time-variable exposure profiles (e.g. profiles from FOCUS surface water modelling) of beta-cyfluthrin.

中文翻译：

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拟除虫菊酯β-氟氯氰菊酯随时间变化的暴露对虹鳟鱼生命早期阶段的影响建模。

背景

现有文献和监管研究表明，β-氟氯氰菊酯（一种合成拟除虫菊酯）对鱼类影响的严重程度受到接触程度和持续时间的影响。为了研究β-氟氯氰菊酯的暴露模式（恒定与峰值）如何影响鱼的反应，我们使用机械效应模型来预测虹鳟鱼在其早期生命阶段（即卵、鱼和鱼）的存活和生长。游上来的鱼苗）。我们将毒代动力学-毒动力学（TKTD）模块与动态能量预算模型相结合进行参数化，使我们能够描述吸收和消除，并预测生存和亚致死效应（摄食行为和生长）的阈值浓度。该效应模型使用早期生命阶段实验的数据进行校准，其中鳟鱼暴露于恒定浓度的氟氯氰菊酯。通过将模型预测与虹鳟鱼早期生命阶段的脉冲暴露研究的独立数据进行比较，对该模型进行了验证。

结果

对行为和生长的影响同时发生，提出了这些影响相互关联的可能性，即摄食行为的损害可能导致食物摄入量减少和生长减慢。因此，我们将“对喂养的影响”作为 TKTD 模块中的作用方式。在较高浓度下，持续接触会导致死亡。该模型能够在校准中充分捕获这种效应模式。该模型能够从定性（响应模式）和定量的角度充分预测鱼卵、鱼卵和游上鱼苗的响应。

结论

由于该模型已成功验证，因此可用于预测β-氟氯氰菊酯在各种实际时变暴露曲线（例如来自FOCUS 地表水模型的曲线）下早期生命阶段的存活和生长。