Environmental Risk Assessment, Waterborne Environmental Inc., Leesburg, Virginia, USA.
Environmental Risk Assessment, Phasera Ltd., Bracknell, Berkshire, UK.
Integr Environ Assess Manag. 2023 Jan;19(1):175-190. doi: 10.1002/ieam.4647. Epub 2022 Jul 4.
Decision-making for pesticide registration by the US Environmental Protection Agency (USEPA) relies upon crop-specific scenarios in a tiered framework. These standard modeling scenarios are stated to represent "…sites expected to produce runoff greater than would be expected at 90% of the sites for a given crop/use." This study developed a novel approach to compare the pesticide runoff + erosion (Sum ) mass flux potential of a hydrophobic chemical using 36 of these ecological regulatory scenarios with national-scale distributions of modeled Sum from over 750 000 USA-wide agricultural catchments to provide real-world context for the simulated transport predictions used for regulatory decision-making. For the standard scenarios and national scale modeling, "edge of field" Sum mass flux was estimated using regulatory guidance for a hypothetical pyrethroid. The national-scale simulations were developed using publicly available soil, hydrography, and crop occurrence /regional timings databases. Relevant soil and crop combinations identified by spatial overlay along with weather data were used in a regulatory model to generate daily Sum estimates, which were assigned to the catchments. The resulting average annual total Sum mass fluxes were ranked to produce distributions to compare with the standard regulatory scenario outputs. These comparisons showed that Sum flux from 25 of the 36 USEPA ecological regulatory crop-specific scenarios modeled ranked above the 99 percentile of pyrethroid runoff + erosion vulnerability from any catchment growing that crop; Sum flux from six scenarios was more severe than any catchment. For 12 USEPA regulatory scenarios, the resulting eroded sediment corresponds to highly erodible land (HEL), which the US Department of Agriculture mandates should not be cropped without substantial additional erosion prevention controls for sustainability. Since the pesticide regulatory framework already incorporates many acknowledged assumptions to ensure it conservatively meets protection goals, these HEL observations suggest that the standard scenarios overestimate potential aquatic exposure and that the regulatory process is more protective than intended. Integr Environ Assess Manag 2023;19:175-190. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).
美国环保署（USEPA）的农药登记决策依赖于分层框架中的特定作物情景。这些标准建模情景据称代表了“……预计产生的径流量大于给定作物/用途 90%的站点的预期。”本研究开发了一种新方法，使用其中 36 个生态监管情景与超过 75 万美国农业流域的全国范围的模拟 Sum 分布，比较疏水性化学物质的农药径流+侵蚀（Sum）质量通量潜力，为用于监管决策的模拟传输预测提供现实世界的背景。对于标准情景和国家规模建模，使用针对拟议拟除虫菊酯的监管指南估计“田间边缘”Sum 质量通量。国家规模模拟使用公开的土壤、水文和作物出现/区域时间数据库开发。通过空间叠加识别的相关土壤和作物组合以及天气数据用于监管模型以生成每日 Sum 估计值，这些估计值被分配到流域。产生的平均年总 Sum 质量通量进行排名，以产生分布以与标准监管情景输出进行比较。这些比较表明，在所建模的 36 个 USEPA 生态监管特定作物情景中的 25 个情景中，Sum 通量的排名高于任何种植该作物的流域中拟除虫菊酯径流+侵蚀脆弱性的第 99 百分位；六个情景的 Sum 通量更为严重比任何集水区。对于 12 个 USEPA 监管情景，产生的侵蚀泥沙对应于高度侵蚀性土地（HEL），美国农业部规定，如果没有大量额外的侵蚀预防控制措施以确保可持续性，不应在 HEL 上种植。由于农药监管框架已经包含了许多公认的假设，以确保其保守地达到保护目标，因此这些 HEL 观察结果表明，标准情景高估了潜在的水生暴露，并且监管过程比预期的更具保护性。《综合环境评估与管理》2023 年；19:175-190。版权所有©2022，作者。综合环境评估与管理由 Wiley Periodicals LLC 代表环境毒理与化学学会（SETAC）出版。
