Baylor University, Department of Chemistry & Biochemistry, Waco, Texas, USA.
Syngenta Crop Protection, Greensboro, North Carolina, USA.
Environ Toxicol Chem. 2018 Sep;37(9):2331-2339. doi: 10.1002/etc.4225. Epub 2018 Aug 8.
The effects of changing hydrodynamic conditions and changing temperatures on polar organic chemical integrative sampler (POCIS) sampling rates (R ) were investigated for 12 crop protection chemicals. Exposure concentration was held constant in each laboratory experiment, and flow velocities were calculated from measured mass transfer coefficients of the water boundary layer near the surface of POCIS devices. At a given temperature R generally increased by a factor of 2 to 5 between a stagnant condition and higher flow velocities (6-21 cm/s), but R for most compounds was essentially constant between the higher flow velocities. When temperature was varied between 8 and 39 °C for a given flow condition, R increased linearly. In general, R increased by a factor of 2 to 4 and 2 to 8 over this temperature range under flow and stagnant conditions, respectively. An Arrhenius model was used to describe the dependence of POCIS sampling rates on temperature. Adjustments of R for temperature did not fully explain observed differences between time-weighted average concentrations of atrazine determined from POCIS and from composite water sampling in a field setting, suggesting that the effects of other competing factors still need to be evaluated. Environ Toxicol Chem 2018;37:2331-2339. © 2018 SETAC.
考察了流态变化和温度变化对极性有机化学整合采样器（POCIS）采样速率（R）的影响，共涉及 12 种作物保护化学品。在每个实验室实验中，暴露浓度保持恒定，根据 POCIS 装置表面水边界层的测量质量传递系数计算流速。在给定温度下，R 通常在静止条件和较高流速（6-21 cm/s）之间增加 2 到 5 倍，但大多数化合物在较高流速下的 R 基本保持不变。当在给定流速下温度在 8 和 39°C 之间变化时，R 呈线性增加。一般来说，在流动和静止条件下，R 在该温度范围内分别增加了 2 到 4 倍和 2 到 8 倍。采用阿累尼乌斯模型描述了 POCIS 采样速率对温度的依赖性。R 对温度的调整并未完全解释在田间条件下，通过 POCIS 和综合水样测定的莠去津时间加权平均浓度之间的差异，这表明仍需要评估其他竞争因素的影响。环境毒理化学 2018；37:2331-2339。©2018 SETAC。
