Datasets used to support the work presented in: Beringer, C.J., K.W. Goyne, R.N. Lerch, E.B. Webb, and D. Mengel. 2020: Clothianidin decomposition in Missouri wetland soils. J. Environ. Qual. JEQ-2020-05-0167-TR

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, i.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.

Methods
Wetland soil samples were collected at eight sites from 0-10 cm depth in locations that contained characteristic wetland vegetation (e.g., Polygonum spp., Cyperaceae spp., Juncaceae spp., Typha spp.)  for Missouri.

新烟碱类杀虫剂（neonicotinoid pesticides）可在土壤中长期残留，同时具备极高的地下水与地表水污染风险。已有研究报道了该类杀虫剂与非靶标生物类群（non-target taxa）间的负面关联，涉及水生无脊椎动物、传粉昆虫及食虫鸟类。

本研究针对密苏里州湿地土壤中噻虫胺（clothianidin，化学名：1-[(2-氯-1,3-噻唑-5-基)甲基]-3-甲基-2-硝基胍，简称CTN）的降解与吸附过程相关影响因素开展评估，以研判湿地土壤缓解新烟碱类杀虫剂相关潜在环境风险的潜力。研究通过单点吸附实验测定了CTN在8种湿地土壤中的固液分配系数（Kd），并选取两种差异最大的土壤开展吸附等温线实验；同时在好氧（oxic）与厌氧（anoxic）条件下开展了为期60天的噻虫胺降解检测，将降解数据拟合至零级与一级动力学衰减模型，以计算CTN的半衰期（t0.5）。

吸附实验结果显示，CTN在湿地土壤中的吸附作用相对较弱（平均Kd=3.58 L·kg⁻¹），表明CTN在湿地土壤中具备迁移性与生物可利用性。但培养实验结果表明，厌氧条件可显著提升湿地土壤中CTN的降解速率（厌氧组平均半衰期为27.2 d，好氧组平均半衰期为149.1 d）。研究发现厌氧条件下的半衰期数值与土壤有机碳含量间存在显著负相关关系（决定系数r²=0.782，显著性p=0.046）。湿地土壤在厌氧条件下更高的CTN降解速率提示，通过湿地管理营造厌氧环境，可降低环境中CTN的残留量，减少其对非靶标生物的暴露风险。

## 方法
本研究从密苏里州的8个采样点位采集0~10 cm深度的湿地土壤样品，所有采样区域均生长有典型湿地植被，包括蓼属（Polygonum spp.）、莎草科（Cyperaceae spp.）、灯心草科（Juncaceae spp.）及香蒲属（Typha spp.）植物。