Neonicotinoid pesticides can persist in soils for extended time periods; however, they also have a high potential to contaminate ground and surface waters. Studies have reported negative effects associated with neonicotinoids and non-target taxa, including aquatic invertebrates, pollinating insect species, and insectivorous birds. This study evaluated factors associated with clothianidin (1-[(2-chloro-1,3-thiazol-5-yl) methyl]-3-methyl-2-nitroguanidine, CTN) degradation and sorption in Missouri wetland soils to assess the potential for wetland soils to mitigate potential environmental risks associated with neonicotinoids. Solid-to-solution partition coefficients (Kd ) for CTN sorption to eight wetland soils were determined via single-point sorption experiments, and sorption isotherm experiments were conducted using the two most contrasting soils. Clothianidin degradation was determined under oxic and anoxic conditions over 60 d. Degradation data were fit to zero- and first-order kinetic decay models to determine CTN half-life (t0.5 ). Sorption results indicated CTN sorption to wetland soil was relatively weak (average Kd = 3.58 L kg-1 ); thus, CTN has the potential to be mobile and bioavailable within wetland soils. However, incubation results showed anoxic conditions significantly increased CTN degradation rates in wetland soils (anoxic average t0.5 = 27.2 d; oxic average t0.5 = 149.1 d). A significant negative correlation was observed between anoxic half-life values and soil organic carbon content (r2 = 0.782; p = 0.046). Greater CTN degradation rates in wetland soils under anoxic conditions suggest that managing wetlands to facilitate anoxic conditions could mitigate CTN presence in the environment and reduce exposure to non-target organisms. This article is protected by copyright. All rights reserved.

中文翻译：

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密苏里湿地土壤中的噻虫胺分解

新烟碱类杀虫剂可以在土壤中长期存在；然而，它们也极有可能污染地下水和地表水。研究报告了与新烟碱类和非目标分类群相关的负面影响，包括水生无脊椎动物、授粉昆虫物种和食虫鸟类。本研究评估了与密苏里湿地土壤中噻虫胺（1-[（2-氯-1,3-噻唑-5-基）甲基]-3-甲基-2-硝基胍，CTN）降解和吸附相关的因素，以评估潜在的用于湿地土壤，以减轻与新烟碱类相关的潜在环境风险。通过单点吸附实验确定了 CTN 对八种湿地土壤的吸附的固-溶液分配系数 (Kd)，并使用两种最对比的土壤进行吸附等温线实验。在有氧和缺氧条件下超过 60 天测定了噻虫胺降解。降解数据适合零级和一级动力学衰减模型，以确定 CTN 半衰期 (t0.5)。吸附结果表明CTN对湿地土壤的吸附相对较弱（平均Kd = 3.58 L kg-1 ）；因此，CTN 具有在湿地土壤中具有移动性和生物可利用性的潜力。然而，孵化结果显示缺氧条件显着增加了湿地土壤中的 CTN 降解率（缺氧平均 t0.5 = 27.2 天；有氧平均 t0.5 = 149.1 天）。在缺氧半衰期值和土壤有机碳含量之间观察到显着的负相关（r2 = 0.782；p = 0.046）。在缺氧条件下湿地土壤中更高的 CTN 降解率表明，管理湿地以促进缺氧条件可以减轻环境中 CTN 的存在并减少对非目标生物的暴露。本文受版权保护。版权所有。