The University of Queensland, National Research Centre for Environmental Toxicology (Entox), 39 Kessels Rd., Coopers Plains, QLD 4108, Australia.
Chemosphere. 2011 May;83(9):1290-5. doi: 10.1016/j.chemosphere.2011.02.089. Epub 2011 Apr 8.
The use of the adsorbent styrenedivinylbenzene-reverse phase sulfonated (SDB-RPD) Empore disk in a chemcatcher type passive sampler is routinely applied in Australia when monitoring herbicides in aquatic environments. One key challenge in the use of passive samplers is mitigating the potentially confounding effects of varying flow conditions on chemical uptake by the passive sampler. Performance reference compounds (PRCs) may be applied to correct sampling rates (R(s)) for site specific changed in flow and temperature however evidence suggests the use of PRCs is unreliable when applied to adsorbent passive samplers. The use of the passive flow monitor (PFM) has been introduced for the assessment of site-specific changes in water flow. In the presented study we have demonstrated that the R(s) at which both atrazine and prometryn are accumulated within the SDB-RPD-Empore disk is dependent on the flow conditions. Further, the calibration of the measured R(s) for chemical uptake by the SDB-RPD-Empore disk to the mass lost from the PFM has shown that the PFM provides an accurate measure of R(s) for flow velocities from 0 to 16cms(-1). Notably, for flow rates >16cms(-1), a non linear increase in the R(s) of both herbicides was observed which indicates that the key resistance to uptake into the SDB-RPD Empore disk is associated with the diffusion through the overlying diffusion limiting membrane. Overall the greatest uncertainty remains at very low flow conditions, which are unlikely to often occur in surface waters. Validation of the PFM use has also been undertaken in a limited field study.
在澳大利亚，当监测水生环境中的除草剂时，通常会在化学收集器型被动采样器中使用苯乙烯-二乙烯基苯-反相磺化（SDB-RPD）吸附剂 Empore 圆盘。在使用被动采样器时，一个关键挑战是减轻变化的流动条件对被动采样器中化学物质摄取的潜在干扰影响。性能参考化合物（PRC）可用于校正特定于采样点的流速变化和温度，但是有证据表明，当应用于吸附剂被动采样器时，PRC 的使用不可靠。被动流量监测器（PFM）已被引入用于评估特定地点的水流变化。在本研究中，我们证明了在 SDB-RPD-Empore 圆盘内积累的莠去津和普草净的采样速率（R(s)）取决于流动条件。此外，将 SDB-RPD-Empore 圆盘对化学物质吸收的测量 R(s)校准为从 PFM 损失的质量表明，PFM 为流速从 0 到 16cms(-1)的 R(s)提供了准确的测量。值得注意的是，对于流速>16cms(-1)，观察到两种除草剂的 R(s)呈非线性增加，这表明进入 SDB-RPD Empore 圆盘的吸收的主要阻力与通过覆盖的扩散限制膜的扩散有关。总体而言，在非常低的流速条件下仍然存在最大的不确定性，这种情况在地表水不太可能经常发生。还在有限的现场研究中对 PFM 的使用进行了验证。
