Improving Risk Assessment by Predicting the Survival of Field Gammarids Exposed to Dynamic Pesticide Mixtures
Improving Risk Assessment by Predicting the Survival of Field Gammarids Exposed to Dynamic Pesticide Mixtures
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DOI：
10.1021/acs.est.0c03939
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发表时间：
2020-10-06
影响因子：
11.4
通讯作者：
Stamm, Christian
中科院分区：
文献类型：
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作者：
Arlos, Maricor J.;Focks, Andreas;Stamm, Christian
随着时间的推移，农药的暴露评估有了很大的改进，现在的方法包括先进的分析技术和归宿/迁移模型的结合，以评估其时空分布。然而，目前的监管环境风险评估考虑的是在标准化条件下完成的实验室研究的阈值，这些阈值不反映环境动态。使用通用统一生存阈值模型 (GUTS) 模型框架，我们预测了随时间变化的农药暴露对小型农业溪流中伽马科动物生存的影响。 LP50 值用作评估风险的附加指标（GUTS 中定义为应用于浓度时间序列的乘法因子，以在暴露结束时诱导 50% 的死亡率）。尽管实际情况下接触各种农药预计对生存几乎没有影响，但 LP50 值表明是急性的 (LP50 100)。最后，模型被扩展以通过浓度添加来反映混合物毒性。它预测了急性和慢性接触有机磷酸盐和新烟碱类杀虫剂的风险。鉴于伽马在其一生中同时暴露于多种化学物质和其他压力源，化学压力导致的生存概率下降可能会影响它们的整体健康状况。我们认识到某些假设需要验证，但我们的工作包括一定程度的现实性，可以在评估化学品暴露的累积后果时帮助风险管理者。
Exposure assessment of pesticides has substantially improved over time, with methods that now include a combination of advanced analytical techniques and fate/transport models to evaluate their spatiotemporal distribution. However, the current regulatory environmental risk assessment considers thresholds from laboratory studies completed under standardized conditions that do not reflect environmental dynamics. Using the General Unified Threshold model for Survival (GUTS) model framework, we predicted the impact of time-varying pesticide exposures on the survival of gammarids in a small agricultural stream. The LP50 values were used as an additional metric for assessing risks (defined in GUTS as a multiplication factor applied to the concentration time series to induce 50% mortality by the end of exposure). Although real-case exposures to individual pesticides were predicted to produce little to no impact on survival, the LP50 values indicate acute (LP50 100). Finally, the model was extended to reflect mixture toxicity via concentration addition. It predicted risks under acute and chronic exposures to organophosphates and neonicotinoids. Given that gammarids are simultaneously exposed to multiple chemicals and other stressors throughout their lifetime, a decline in survival probabilities due to chemical stress can likely influence their overall fitness. We recognize that some assumptions require validation, but our work included a level of realism that can assist risk managers when evaluating the cumulative consequences of chemical exposure.