Global Water Program, Johns Hopkins University, Baltimore, MD 21205, USA.
Environ Monit Assess. 2013 May;185(5):3613-24. doi: 10.1007/s10661-012-2813-8. Epub 2012 Aug 14.
The ability to sample in situ natural environmental processes has proven to be challenging when working with redox-sensitive contaminates in saturated sediments in wetland systems, especially within the rhizosphere, where sharp redox gradients are common. Many traditional approaches are invasive and disturb natural sediment chemistry. Through laboratory and field studies, the work presented in this study demonstrates a novel semipermanent dialysis sampler that allows for long-term, anaerobic monitoring of shallow sediments. Dialysis samplers were deployed and tested for over 1 year while being exposed to extremes in climate. These newly designed devices produce statistically reproducible data and capture sensitive redox trends. Results from the newly designed samplers were compared to conventional samplers. Initially, both the new and old designs yielded statistically similar data, but these data diverged over a period of months. The new devices are less invasive, so data gathered from these devices are more likely to be a closer representation of true conditions in the subsurface. By giving reliable data from a consistent location in space, these new samplers represent a significant step forward in capturing spatial and temporal variability in wetland redox chemistry during long-term monitoring.
在湿地系统中，对饱和沉积物中氧化还原敏感污染物进行原位自然环境过程采样，这一直是一项具有挑战性的工作，特别是在根际，这里通常存在明显的氧化还原梯度。许多传统的方法具有侵入性，会干扰自然沉积物的化学性质。通过实验室和现场研究，本研究中介绍的工作展示了一种新型的半永久性透析采样器，该采样器可用于对浅层沉积物进行长期的厌氧监测。透析采样器在暴露于极端气候的情况下部署和测试了超过 1 年。这些新设计的设备可产生具有统计学重现性的数据，并捕捉到敏感的氧化还原趋势。将新设计的采样器的结果与传统采样器进行了比较。最初，新设计和旧设计的数据在统计学上都相似，但这些数据在数月的时间里出现了分歧。新设备的侵入性较小，因此从这些设备收集的数据更可能更接近地下真实情况的代表。通过在空间上的一个固定位置提供可靠的数据，这些新的采样器在长期监测中捕捉湿地氧化还原化学的空间和时间变异性方面向前迈出了重要一步。
